NBSIR 74-567

FY 74 Progress Report on Design

Criteria and IMetliodology for Construction

of Low-Rise Buildings to Resist Typhoons

and Hurricanes

N. J. Raufaste, Jr. and R. D. Marshall

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

July 1,1974

Interim (July 1, 1973 through June 30, 1974)

Prepared for The Office of Science and Technology

Agency for International Development

Department of State

Washington, D. C. 20523

Under a Participating Agency Service Agreement (PASA)

No. TA(CE) 04-73

NBSIR 74-567

FY 74 PROGRESS REPORT ON DESIGN

CRITERIA AND METHODOLOGY FOR CONSTRUCTION

OF LOW-RISE BUILDINGS TO RESIST TYPHOONS

AND HURRICANES

N. J. Raufaste, Jr. and R. D. Marshall

Center ^or Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

July 1, 1974

Interim (July 1, 1973 through June 30, 1974)

Prepared for The Office of Science and Technology

Agency for International Development

Department of State Washington, D. C. 20523

Under a Participating Agency Service Agreement (PASA)

No. TA(CE) 04-73

M.

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

CONTENTS

TABLE OF FIGURES 11

SI CONVERSION FACTORS. .

' iv

ABSTRACT v

INTRODUCTION 1

A. SUMMARY OF PROGRESS FOR FISCAL YEAR 1974 4

Background Information. . . ^ Wind Research Activities 6

Field Test Sites 6

Research Equipment 11

Wind Tunnel Modeling 14

Collection, Reduction and Analysis of Field Data .... 21

Assessment, Selection and Application of

Cllmatological Data 25

International Workshop on Effects of Extreme Winds 25

Library Research 26

Information Transfer to Other Wind Areas 26

Soclo-Economic and Housing Study 27

Philippine Housing Construction Practices 29

B. EXPECTED PROGRESS THROUGH PROJECT COMPLETION 39

Full-Scale Studies 39

Wind Tunnel Studies 39

Development of Design Pressure Coefficients 39

Soclo-Economic Analysis 40

Computer-Generated Motion Picture Film 40

Regional Conferences 40

C. FISCAL YEAR 1975 PROJECT SCHEDULE 41

APPENDIX A: Minutes of the 1st - 6th Philippine Advisory

Committee Meetings A-1

APPENDIX B: "Simulations of Atmospheric Flows in Short Wind

Tunnel Test Section" B-1

APPENDIX C: Bibliography of Wind Related Documents C-1

APPENDIX D: Housing and Wind Problems in the Northern

Caribbean and Indian Ocean Countries D-1

APPENDIX E: Housing in Extreme Winds E-1

i
TABLE OF FIGURES

Figure Page

1 Building test sites 8

2 Wind research equipment undergoing final inspection by NBS

team member prior to shipment to the Philippines by the

' USAF Military Airlift Command 9

3 The first (bottom) and second (top) test houses were

; instrumented for winds in September and November respectively,

s ^ Note the pressure transducers (round disks) located on the

corrugated iron roofs; others are fastened on the walls 10,

4. Aerial view of instrumented test building at Daet Weather

Station 12

5 ^ Typical installation of ground anchors by PAGASA technicians

prior to erection of meterological tower ' 15

iS PAGASA technicians assembling tower section 16

,7 Erecting 10-meter meteorological tower which supports the

anemometer and ambient pressure probe. Note guy wires

running to ground anchors 17

:8 Of f icer-in-charge at Daet Station receiving instructions on assembly of pressure transducer from member of PAGASA

Headquarters staff 18

9 Typical installation of pressure transducers and signal cables

on a test building roof .19

10 Installed pressure transducers on a test building at

Laoag City 20

11 Member of NBS research team instructing staff of the National

Center for Hydraulic Research (at the UP) in the operation

of wind tunnel test equipment 22

12 Photograph of 1:80 scale model of field test house installed

in UP wind tunnel. This is a view looking upstream. Note

ball point pen for scale 23

ii
TABLE OF FIGURES (Contd.)

Figure Page

13 Shallow trench for wall placement 30

14 Wall construction quality and window framing details 30

15 Wall pier and roof bearing detail 32

16 Corner column reinforcement 32

17 Column reinforcement anchorage to roof rafters 33

18 Completed column and roof anchorage 33

19 Roof anchorage detail 34

20 Detail of corner column and exterior wall 34

21 Window framing detail 35

22 Exterior appearance of completed structure 35 |

23 Roof to truss anchorage detail 37 '

24 Wall damage resulting from Typhoon Yoling, November 1970 38

25 Wall and roof damage resulting from Typhoon Yoling,

November 1970 38

I

iii
SI CONVERSION FACTORS

This report describes measurements in metric units. It is

recommended that the reader assume the responsibility for applying

the appropriate conversion to English units. The United States

of America, as a signatory to the General Conference of Weights

and Measures (which gave official status to the metric SI system

of units) , recognizes the International Standard (SI) unit of

measurement

.

Length

1 centimeter (cm) = 0.394 inch (in)

1 meter (m) = 3.281 feet (ft)

1 kilometer (km) = 0.622 mile (mi)

Velocity

1 centimeter per second (cm/s) = 0.394 inch per second (in/s)

1 meter per second (m/s) = 3.281 feet per second (ft/s)

IV
ABSTRACT

This report presents the major accomplishments of the second phase

of a three year project to provide engineering and technical assistance

to the Agency for International Development (AID) , Department of State

in developing improved design criteria for low-rise buildings to better

resist extreme winds. During Fiscal Year 1974, project staff members of

the Center for Building Technology, National Bureau of Standards, Washingt

D. C. 20234 commenced several tasks. These tasks will serve as major

inputs to the development of improved design criteria. The principal

tasks included: 1) selecting a second and third field test site in the

Philippines, 2) instrumenting four full-scale houses at the sites, 3)

instrumenting the University of Philippines wind tunnel facility, 4)

helping arrange and participating in an international workshop at Manila

during November 1973, and 5) developing in conjunction with short-term

consultants in Bangladesh and Jamaica a methodology for the transfer of

the technology to those areas.

v

INTRODUCTION

The National Bureau of Standards (NBS) through this project is

developing improved design criteria for low-rise buildings in

developing countries to better resist the effects of extreme winds. The

project is sponsored by the Agency for International Development (AID)

under Participating Agency Service Agreement (PASA) No. TA(CE)

04-73 with funding under AID's central research program. The overall

management is provided by William H. Littlewood, Associate Director,

Office of Science and Technology, AID.

This research project originated from recognition of a need for

additional research to supplement the limited amount of existing data

regarding the wind effects on low-rise buildings, especially in developing

countries. The existing criteria for wind loads in developed countries

do not make provisions for steady and fluctuating wind pressures along

the edges of roofs and walls where flow separation occur. Yet wind flows

along these regions are one of the primary contributors to building

damages. This research and the resultant development of suitable design

criteria and methodologies will provide high benefits in reducing losses

of structures and lives in the countries where the criteria are applied.

The Philippines experience the highest worldwide annual frequency

and intensity of tropical storms. Within the Philippines, the frequency

of tropical storms is greatest in Luzon. Statistics indicate that

between 1948 and 1971 the Philippines were exposed to 482 tropical

storms, or an average of 20 per year. As such, these occurrences make

the Philippines a natural laboratory to measure wind loads on buildings.

The Philippines, consisting of over 7,100 islands, are located

approximately 800 kilometers off the coast of southeast Asia. The

archipelago extends north and south for approximately 1600 kilometers at

its widest part.

The Philippines are generally divided into three regions: Luzon,

the northern section: the Visayas, Palawan and Mindoro, the central

section; and Mindanao and the Sulus, the southern section. Approximately

37 percent of the land area is included within Luzon, 29 percent in the

Visayas area and 34 percent in Mindanao. There are about 90 different

dialects spoken among the Philippine population of over 37 million people.

NBS's extreme wind study includes several components. It is based

largely on field work (collection of wind loading data from seven field

test buildings) and from wind tunnel testing of building scale models.

The study also includes a review of climatological data from the weather

bureaus of the Philippines and two other developing countries, Bangladesh

and Jamaica. Socio-economic, architectural and structural data, and codes

and standards information from the Philippines and other developing

countries will be included in the implementation aspects of this study.

In addition, knowledge about wind effects on buildings obtained in other

countries such as the United States, Japan. Australia and the United

Kingdom will be used as required.

"Climatology and Wind Related Problems in Philippines" by R. L. Kintanar,

November 1973, Manila, Philippines (Paper presented at a workshop

in Manila, Philippines)

.
The following Fiscal Year 1974 Project Status Report discusses the

principal activities and accomplishments during the period July 1, 1973

through June 30, 1974. Also included is a summary of activities accomplished during the period from March 1973 to June 1973, the initial phase

of the project."'"

During FY 74 five principal tasks were completed. The tasks were:

a) selection of a second and third field test site at Daet and

Laoag City (the first was selected at Quezon City in FY 73)

,

b) instrumentation of four of seven test houses and appropriate

training of technical personnel by the NBS project team at the

three field test sites (with three more to be instrumented by

the Filipinos)

,

c) instrumentation of the University of Philippines wind tunnel

facility, with appropriate training of the technical personnel,

d) participation in an international workshop in Manila during

November 14-17, 1973 (proceedings of Workshop will be

published during the Summer of 1974), and

e) selection and award of contract to short-term consultants

to transfer research results to other wind-prone geographic

areas (Bangladesh and Jamaica)

.

Each of these tasks was completed. It should be noted, the above

items "b" and "c" include a teaching component. The wind tunnel

training will be an on-going and continuous activity throughout the life

of the project.

Other work accomplished during FY 74 included:

, a) initial assesment of Philippine climatological data,

b) continuation of library research of related subject documents,

c) preliminary analysis of wind data collected on test house

Number 1 (Quezon City) during two October 1973 storms,

d) preliminary analysis of socio-economic and housing considerations and

e) preliminary analysis of Philippine housing construction practices.

For additional information about the initial project phase references,

see NBS report to AID entitled Fiscal Year 1974 Project Status ReportDesign Criteria and Methodology for Construction of Low-Rise Buildings

to Resist Typhoons and Hurricanes , July 3, 1973, available from the authors.

2
This report highlights the major results of each of the above tasks

and presents general overall impressions. Where factual material is

available, it is presented. Where the findings are based on interpretation of the available data, the underlying assumptions are given. The

details of the task accomplishments are given in the next section of

the report. This is followed by a discussion of the anticipated progress

and plans for Fiscal Year 1975. Appendices found at the back of the

report provide the reader with supplemental information about specific

task accomplishments

.

Five appendices are included:

Appendix A - Minutes of the lst-6th Philippine Advisory Committee

Meetings

Appendix B - Simulation of Atmospheric Flows in Short Wind Tunnel

Test Sections.

Appendix C - Bibliography of Wind-Related Documents

Appendix D - Housing and Wind Problems in the Northern Caribbean

and Indian Ocean Countries

Appendix E - Housing in Extreme Winds

3
A. SUMMARY OF PROGRESS FOR FISCAL YEAR 1974

Background Information

The first step in the initial research (FY 73) was to identify

interested organizations, agencies, universities and other groups within

the Philippines, selected Indian Ocean countries and several northern

Caribbean islands, and to assess their degree of interest for possible

in-country project participation. On April 27, 1973 the first major

milestone occurred — the formation of the Philippine Advisory Committee.

Professionals from various building related fields were brought together.

The response from the Philippine Government and the private sector

numbered more than 30 scientists, engineers and researchers representing

9 government entities, four professional organizations and two private

groups. Also included were the USAID Mission, to the Philippines and the

U. S. National Bureau of Standards. The Philippine Advisory Committee

serves as the focal point for coordinating project activities centering

in the Philippines.

Since the initial formation of the advisory committee four additional

groups have joined. Currently the committee is composed of the following:

• University of the Philippines (UP)

• Philippine Atmospheric Geophysical and Astronomical Services

Administration (PAGASA)

• National Housing Corporation (NHC)

• Land and Housing Development Corporation (LHDC)

• Peoples HomeSite and Housing Corporation (PHHC)

• Government Service Insurance System (GSIS)

• Social Security System (SSS)

• Philippine Standards Association (PSA)

t A. R. Flores and Associates

• National Building Code Committee

• Concio and Associates

• Association of Structural Engineers of the Philippines ,

• Philippine Institute of Civil Engineers

• Bureau of Public Works (BPW)

4
• Philippine Civil Aeronautics Administration (CAA)

• National Science Development Board (NSDB)

• USAID Mission to the Philippines

• Bangladesh University of Engineering and Technology

• CARE, Inc. - Bangladesh

• Douet, Brown, Adams and Associates, Jamaica

• U. S. National Bureau of Standards

In addition to NBS and AID support, principal members from the

above groups personally donated their time and professional expertise;

test buildings; land to construct test buildings; scientific facilities

and funding for continuation of appropriate Philippine research activities.

For example. The University of Philippines (made available their wind

tunnel facility for scale model testing. They also provided over one man year of research associate services to operate the tunnel and onethird man year of construction laborers' time to modify the wind tunnel

facility. The Philippine Atmospheric Geophysical and Astronomical

Services Administration committed three parcels of land at Quezon City,

Daet and Laoag City as sites for six test buildings. The PAGASA permitted

their main building at the Daet weather station to be instrumented.

They also provided about one-quarter man year of technicians' time to

instrument the test buildings and operate and maintain the equipment.

The Philippine Civil Aeronautic Administration donated a parcel of land

at Laoag City for one test building and a meteorogical tower. The

World Meteorological Organization United Nations Development Program

donated one jeep for surface transportation trips to the field sites

(Daet and Laoag City)

.

The National Housing Corporation donated the first test house, at

the Quezon City site. The value of this donation is about 10,000 pesos

($1,500 US). The Land and Housing Development Corporation donated the

second test house at Quezon City. The house is valued at about 12,000

pesos ($1,800 US). The Government Service Insurance System donated two

test houses at Laoag City, houses are valued at about 15,000 pesos

($2,000 US). CARE, Inc. -Bangladesh donated a 200 square foot barrel

vaulted house at Quezon City for instrumentation. They also absorbed

the transportation costs to transport it from Bangladesh. It is expected

that the Peoples Homesite and Housing Corporation will donate a house at

Daet during the summer of 1974 (financial problems caused PHHC to

postpone their Spring 1974 construction schedule) . The University of

Philipp ines constructed a new air conditioned equipment room adjacent to

the wind tunnel. They are also absorbing the costs for computer runs.

Many of the above and other committee members provided services by

hosting meetings, co-sponsoring an International Workshop and donating

money for a general project fund.

5
The second milestone in the initial project activity was the

identification of two individuals to represent the Indian Ocean countries

and the northern Caribbean Islands. These individuals will transfer

information about their respective geographic areas as inputs to the

development of final design criteria, and will also transfer the project

results to their respective geographic areas. Additional information

about consultant activities is provided later in this report.

Lastly, it should be mentioned that the USAID Mission to the Philippines

provided the NBS research team with a base of operations, for limited

logistical and advisory services. The Mission's Capital Development

Office USAID/Philippines , serves as a focal point for the NBS interactions

while NBS personnel are in the Philippines. Mr. William C. Larson,

Assistant Director for Capital Development, the NBS team's primary point

of contact, has recently left the Philippines after serving three consecutive

tours of duty. His replacement, Mr. Richard Dangler (from AID/Washington,

D. C.) has already been briefed on the overall project. Mr. Larson's

interest and help is greatly appreciated.

Appendix A "Minutes of the lst-6th Philippine Advisory Committee

Meetings" will provide a more complete overview of the project activities.

The strong Philippine and Mission support has provided a firm base

which permitted the FY 74 activities described herein to occur smoothly

and on schedule.

Wind Research Activities

a) Field Test Sites

Three field test sites are being operated under the full-scale

phase of the test program. In order of selection and installation of

equipment, they are as follows; (1) Science Garden at Quezon City,

(2) Daet and (3) Laoag City. A number of factors had to be considered

in selecting these test sites and the final choices required some compromise

in the original selection criteria. The main factors in order of importance were as follows:

• High frequency of extreme winds,

• Statistical independence,

• Accessibility,

• Availability of commercial power,

' • Type of wind exposure, and a

• Security

The Science Garden site was an obvious choice since it is staffed with

qualified PAGASA technicians. These technicians form the nucleus of a team trained by NBS in the installation, operation and maintenance of

6
test equipment. It was thus possible for the NBS team members to transfer

a significant portion of the installation work and associated responsibilities during the early stages of the program. Science Garden also serves,

in conjunction with the University of the Philippines, as the center for

reference standards, spare parts and service equipment.

Selection of the remaining sites was not so obvious. It had been

concluded in the initial stage of the program that PAGASA weather

stations would be used because of the security and personnel available

to service the equipment. In addition, measurements of temperature and

barometric pressure would be available, thus freeing data channels for

additional pressure measurements. In discussions with the Philippine

Advisory Committee, serious consideration was given to sites at Virac,

Casiguran, Aparii, Baguio City, Daet and Laoag City. Virac and Baguio

City were eliminated on the basis of unusual terrain features (mountain

top locations) which are not typical of wind exposures for housing

developments and would be extremely difficult to model in the wind

tunnel. Casiguran was eliminated because of the difficulties of transporting

equipment and personnel for periodic maintenance and calibration (boat

service only) . Aparii was eliminated because of plans to relocate the

present PAGASA weather station site, and the lack of electrical power.

Daet and Laoag City were selected with some compromise on statistical

independence (Daet) and frequency of extreme winds (Laoag). However, it

is believed that other attributes of these sites more than offset these

compromises (see fig. 1 for test site locations).

Arrangements were made with the Philippine Advisory Committee to

build test houses at the sites and, where possible or necessary, to use existing PAGASA structures. Test equipment was assembled, tested,

calibrated and packaged at the NBS for shipment to the test sites. One

such shipment is shown (fig. 2) prior to transportation to the Philippines.

The United States Air Force (USAF) provided authorization for two NBS

project personnel to accompany the research equipment on USAF Military

Airlift Command (MAC) aircraft from Dover AFB , Delaware to Clark AB,

Philippines. Three such trips were arranged during FY 74.

Where possible, the signal cables, attaching hardware, etc. were

specially made up at NBS for each site to reduce the amount of field

work and installation time to a minimum. At the same time, spare cables

and fixtures were shipped to and stored at the Science Garden so that

unforeseen changes in test house geometry and location could be accommodated.

A description of the respective sites and their status as of May 30,

1974 is given below.

1) Science Garden, Quezon City . The wind exposure at this site varies

with wind direction, being relatively clear and flat from N to SE and

slightly rough from SE to W due to construction of high-rise buildings

some 1000 meters away. The site is moderately rough from W to N due to

local topographical features and low-rise buildings on the test site.

Two test houses are currently instrumented and a third house will be

instrumented in July, 1974. Basic plan dimensions of the first two

units are 9 x 10 meters (see fig. 3) . The third unit was constructed by

CARE, Inc. in Bangladesh and shipped to Quezon City for full-scale testing.

7
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10
This building is barrel vaulted in end elevation and has plan dimensions

of 5.4 X 2.5 meters. A more detailed description of this structure can be found in previous NBS progress reports. The data acquisition system

is located in the PAGASA Instrumentation Building (adjacent to the first

test house) which is air conditioned and relatively free from dust. A

total of 21 pressure channels are available (an increase of 7 channels

through use of an auxiliary

signal conditioning system)

.

2) Daet Weather Station . The Daet site is approximately 230 km SE of

Manila. It is located next to the city airport which borders the Pacific

Ocean. The site has a very flat and clear exposure with the exception

of a coconut grove running from NE to SE adjacent to the ocean. Due to

financing problems, the two test houses planned for Daet have not been

constructed. It was therefore necessary to instrument the main PAGASA

Station Building behind the radome (see fig. 4) . This is the only

building under test which has a hip roof. The data system is installed

in the main building's radar equipment room which is air conditioned.

An emergency generating system is available at this site in the event

that commercial power service is disrupted.

3) Laoag City Weather Station . This site is approximately 450 km

north of Manila. As with Daet, the site is adjacent to the municipal

airport and has a clear and flat exposure for all directions. Two test

houses with plan dimensions identical to the test units at Science

Garden (but with different roof slopes and eaves overhang)

have been constructed, one on the PAGASA station grounds and one on CAA

property. The unit that is currently instrumented is located in close

proximity to two existing buildings which will allow the influence of

neighboring structures to be evaluated. Since no air conditioning is

available at this site, it was decided to install the data acquisition

system in the smallest room of the test house and add air conditioning

at the time of the next trip (July 1974) . The second test house will

also be instrumented at that time.

b) Research Equipment

(1) Full-Scale Test Equipment . Based on technical needs, some of

the data acquisition equipment was specially developed at NBS while

the balance was specified. The data acquisition systems used in the

full-scale test program consist of five basic subsystems; (1) the sensors

or transducers, (2) a logic section, (3) a signal conditioner, (4) a recorder, and (5) a power supply. The equipment was assembled, tested

and packaged for shipment to the Philippines by NBS project staff.

These systems are designed to continuously monitor input signals

and to go into a calibration and record sequence when the signal being

monitored exceeds a preset level. When the recording period has ended,

the system enters a "hold" period during which no data are collected,

regardless of the signal level on the channel being monitored. The

"record" and "hold" periods are switch-selectable and are usually set at

20 and 30 minutes, respectively. The total recording time available on

a reel of tape is approximately 6 hours. Thus, the total time period

between changes in tape reels (assuming continuous high wind conditions)

is approximately 12 hours which is considered to be sufficient for most

typhoon passages.

11
12
Wind speed and direction are measured by a propeller-vane anemometer

mounted on a 10-meter mast located far enough from the test buildings to

register conditions in the undisturbed wind field. The anemometer is

rated at 100 m/s and provides the signal which triggers the recording

system. An ambient pressure probe is also mounted on the mast just

below the anemometer and provides the differential pressure transducer

with a standard reference pressure. The pressure transducers are mounted

in low-profile housings which are designed to create a pressure intensity

at their center equal to the pressure that would exist on the surface of

the building without the housings installed. This obviates the problems

involved with mounting the transducers flush with the wall or roof

surfaces. The transducers are fitted with a solenoid valve which is

activated by the logic system one minute before the generation of pressure

records begin. This valve places the transducer in a "closed-loop"

configuration, thus allowing the subsequent record to be corrected for zero offset due to thermal drift or loading of the transducer diaphragm

with rainwater.

The logic portion of the data acquisition system normally operates

in an automatic mode, but provisions exist for manual intervention for

the purpose of calibration or periodic system checkout. The logic

section also includes a time code generator which provides both digital

and analog code of Greenwich Meridian Time (GMT) in days, hours, minutes

and seconds. The time code generator is set by radio countdown from

PAGASA Headquarters in Quezon City and normally requires correction only

two or three times a year.

Analog signals from the pressure transducers are converted to DC

voltages (demodulation) and filtered by the signal conditioner prior to recording. The signals are also attenuated to match the range of the

tape recorder, thus providing a better signal to noise ratio than would

be possible by straight recording of the transducer outputs.

The recording section consists of a 14-track analog tape unit with

26.7 cm reels containing 1097.3 meter of tape. Usual record speed is

4.8 cm/sec. The recorder is normally in a "powered down" mode and only

operates on command from the logic section. As with the logic section,

manual intervention is permitted for calibration, cleaning and rewinding

tape. Recorded signals can be reproduced in the field to check recorder

operation.

With the exception of the Laoag City test site, commercial power is

used to operate the data acquisition systems. The Laoag City site is

provided power by the CAA. To ensure availability of power under storm

conditions, all three sites are equipped with a backup system of batteries.

The batteries are continuously charged when external power is available

and provide system power (115VAC) by means of an inverter. When commercial

power is interrupted, the batteries automatically switch on and pick up

the load to supply the data acquisition system for approximately 8 hours

of continuous operation. The batteries are recharged automatically when

service is restored.

13
Typical installations of test equipment are shown in figures 5 through

10. Since typhoon winds can be expected to come from any direction, it

is extremely difficult to determine a "best" configuration of pressure

transducers. Because roof structures are known to be the most susceptible

to wind damage, they received the highest priority in transducer allocations.

Extreme pressures acting along ridge lines, eaves and roof corners are

of interest as well as the average uplift pressures acting on the overall

roof area. As such the conf irguration of pressure transducers are arranged differently on each test building, thus providing the ability

to measure a greater range of wind loadings. The building in the upper

right corner of figure 3 was instrumented to give information on the

correlation of pressure fluctuations along the centerline on both sides

of the roof structure, while the building in figure 10 was instrumented

to give information on localized pressure fluctuations. In all of the

test buildings, transducers were installed inside the building to measure

internal pressures which significantly influence the net roof uplift

loads

.

(2) Wind Tunnel Test Equipment . Test equipment being used in the

wind tunnel can be divided into three categories; (1) pressure transducers,

(2) wind speed measuring equipment, and (3) signal conditioning and

analysis equipment. The pressure transducers are quite similar to those

being used in the full scale tests except for the cylindrical transducer

housings. Normally, four transducers are installed in the building

model although six units are available.

Wind speeds are measured by pitot tubes when mean values are required. For measurement of wind speed fluctuations, hot-wire aneno- meters are used. The anemometers have an extremely high frequency

response and are well suited to making measurement over the frequency

range of interest (0 to 500 Hz). Two anemometer systems are used,

permitting simultaneous measurements at two points in the tunnel for the

determination of integral scales (size of wind gusts). The second

system also provides backup if a component should fail. A discussion of

experimental techniques and data processing is included in another

section of this report.

c) Wind Tunnel Modeling

The wind tunnel facility at the National Hydraulic Research Center

(NHRC) , University of the Philippines, is being used to carry out a series of tests on models of the full-scale test buildings. The cross section of this tunnel is 1.22 meters square and 3.70 meters long and

produces a wind speed of approximately 30 meters per second. These

model tests will aid in the interpretation of full-scale studies and

will allow design pressure coefficients to be determined in a systematic

manner

.

(

14
I 15
16
Figure 7 Erecting 10-meter meteorological tower which supports the

anemometer and ambient pressure probe. Note guy wires

running to ground anchors

I

17
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18
19
20
While it is not possible to exactly model atmospheric boundary

layers in conventional wind tunnels, an acceptable degree of similitude

can be achieved by proper use of surface roughness elements and vortex

generators. The technique being used in the NHRC tunnel hass been used

in previous wind tunnel model studies and was perfected for this application

in a slightly larger but quite similar wind tunnel at Colorado State

University (CSU) . Tapered spires are placed at the entrance to the test

section to produce a sheared flow of arbitrary turbulence intensity.

The spires are followed by several rows of roughness elements located on

the floor of the wind tunnel. The roughness elements generate a turbulent

boundary layer which extends to almost the full height of the tunnel at

the downstream end of the test section. Two combinations of spires and

surface roughness elements^ were developed which produce turbulent boundary

layers typical of smooth and moderately rough terrain, respectively.

The model scale being used in these studies is 1:80. Ideally, this

scale should be dictated by the integral scale of the turbulence, the

effective surface roughness height and the length associated with the

peak of the turbulent energy spectrum. Test results obtained in the CSU

studies suggest a scale ratio of from 1:100 to 1:200. However, the

physical size of the model precludes installation of pressure transducers

at these small scales. Thus a compromise of 1:80 was used. Preliminary

test results and results obtained in other wind tunnel model investigations

suggest that scale matching is of secondary importance compared to

intensity of turbulence and shape of the spectral density function. A

report covering the CSU studies is included as Appendix B.

In addition to the wind tunnel modeling as described above, the NBS

developed, specified, obtained and transported various items of test

equipment for the UP wind tunnel facility. The equipment was installed

in the wind tunnel and training sessions were conducted in the operation

of equipment and the interpretation of test results (see fig. 11).

Major items of equipment transferred to the University of the Philippines

include a signal correlator and probability analyzer, hot-wire anemometers,

pressure transducers, electronic filters, signal amplifiers, x-y and

stripchart records, voltmeters and an oscilloscope. This test equipment

is housed in an air conditioned room built by the University. A typical

plexiglass building model installed in the wind tunnel is shown in figure 12.

Computer programs developed at the NBS for the analysis of random data

are being transferred to the UP Computer Center. In addition, an extensive collection of documents dealing with the wind tunnel modeling

of buildings and other engineering structures was placed in the UP

Library. The list of documents is included in Appendix C.

d) Collection, Reduction and Analysis of Field Data

All data collected at the field test sites are recorded on analog

magnetic tapes which are shipped in special containers to the NBS for

processing. Typically, these tapes contain one channel each of wind

speed and direction data, 11 channels of pressure data and one channel

of time code. Prior to the recording of data, a tape is assigned a site

designation and tape identification number. This information, along

with the time code, uniquely identifies the data.

21
22
Figure 12 Photograph of 1:80 scale model of field test house installed

in UP wind tunnel. This is a view looking upstream. Note

ball point pen for scale

23
The first step in the data reduction process is to record certain

key channels, such as wind speed, wind direction and a representative

pressure signal on a paper stripchart and subjectively classify the

records by degree of stationarity . Those records exhibiting significant

trends are eliminated during this screening process. Records which

contain redundant information are also eliminated at this time. The

remaining records are then viewed on an oscilloscope to determine the

approximate maximum or minimum peak values and to verify that the recordings have an acceptable signal to noise ratio and are free of discontinuities. Once the records are determined to be of acceptable quality,

they are converted to digital form for analysis.

Analog to digital conversion is accomplished by means of a computercontrolled data aquisition system which scans the analog channels in

sequence and converts the voltage levels into binary equivalents. The

data channels are multiplexed at a rate of 20,000 channels per second so that the time skew is negligible for the frequency range of interest.

The scan rate can be varied but is typically 12 scans per second. Each

channel is sampled 12,000 times, resulting in a record length of 1000

seconds (16 min - 40 sec) . The multiplexing stage is followed by a programmable amplifier which allows best use of the digital representation

(eleven binary bits plus sign) . The digital data are entered on a 7-

track magnetic tape for subsequent analysis in the NBS Computer Center.

This tape also contains header information such as site and tape identification,

the time of day when the original data were recorded, and the length of

record

.

Several programs were developed at the NBS for the analysis of

random data. These include; Probability Density Function which

determines the peak values (either maximum or minimum) between zero crossings, calculates the mean and root mean square values and

plots probability distribution functions; Correlation Analysis

which calculates correlation functions and spectral density estimates;

and a Summation Program which calculates the area-averaged

surface pressures and the drag and uplift forces acting on a structure.

As of May 30, 1974, a total of 8 records were obtained at the

Science Garden site, Quezon City, from two storms passing near Manila

during October 1973. These records are currently being analyzed. The

outputs are expressed in terms of dimensionless coefficients which

will be used in developing the design criteria. These coefficients are described in another section of this report.

Data obtained from the wind tunnel are processed "on line" and are

not recorded for future reduction or analysis. A hybrid computer allows

the direct calculation of auto- and cross-correlation functions as well

as probability density and distribution functions. A time domain analyzer

is used to obtain direct measurements of mean and rms values. This

system has the disadvantage of manual calculation of pressure coefficients, but this is insignificant when compared with the ability to quickly

assess the test results and alter the model configuration without waiting

for results from a central computer.

24
e) Assessment, Selection and Application of Climatological Data

A study of the available Philippine wind climate information with a view of assessing its adequacy from a structural engineering viewpoint

will continue throughout the life of the project. Records of wind

speeds, of typhoon observations and damages due to significant typhoons were collected by NBS through the courtesy of the PAGASA. Out of these

records, data were selected which appear to be suitable for analysis.

These will be used as input in programs available at NBS for predicting

extreme winds corresponding to various recurrence intervals. A listing

of the NBS program will be sent to the PAGASA Computer Center for future

adoption by the PAGASA as a calculation tool. The Computer Center would

assume the task of adopting the program for use in their facilities.

NBS would provide appropriate assistance as required.

A parallel study of wind maps including the 1972 National Structural Code for Buildings of the Association of Structural Engineers of

the Philippines and tropical cyclone frequency and intensity maps

reveal the area of northern Luzon, and perhaps parts of Western Luzon

(including Manila) may need to be included in a more intense wind zone

area. This topic was discussed with the supervising Meteorologist of

the PAGASA Climatological Division who confirmed, on the basis of his

studies, the need to update the Structural Code wind map to insure a consistent and more adequate degree of safety for buildings. It is

desirable that future editions of the building code differentiate between

zones with different exposure (e.g. urban terrain vs. coastal sites).

Results from this task will provide the appropriate Philippine code

officials with much needed information for incorporation in a new building

code. This information will serve as an input to the final report.

International Workshop on Effects of Extreme Winds

N An International Workshop held in Manila, Philippines on November

14-17, 1973 addressed the state-of-the-art in mitigating building damages

from winds. The workshop was jointly sponsored by AID, the project's

Philippine Advisory Committee and the U.S. National Bureau of Standards.

Four themes covering climatology and aerodynamics, structural

engineering, socio-economic and architectural considerations, and codes

and standards were discussed.

The first two workshop days were devoted largely to presentations of techni'

cal papers. During the afternoon of the first day, a visit was scheduled

to the field test site at the PAGASA Science Garden site, Quezon City.

Nine papers were presented during the technical sessions and five

related reports with time reserved for discussions. The third day was

25
devoted to subcommittee working sessions where 31 recommendations were

developed. They were presented and discussed on the fourth day. Approximately 140 individuals from five countries (Jamaica, Bangladesh, the

United Kingdom, the Philippines and the United States) attended the

workshop.

Subsequent to the workshop the NBS and Philippine Advisory Committee

edited the recommendations and combined several and modified others into

14 recommendations. The proceedings of the workshop will be published

by the NBS in the summer of 1974. The publication will include the recommend

tions for improved building practices, the opening ceremonies, and the

technical papers and reports.

It was the intent of the workshop to identify deficiences in data

gathering procedures, wind effects on buildings, and building practices.

The purpose of the recommendations is to upgrade design criteria for lowcost buildings to a minimum acceptable level, and to suggest

improvements in the building procedure.

Library Research '

As noted in the FY 73 Project Status Report to AID, NBS commenced a task to identify and collect related documents of extreme winds on lowrise buildings. As previously mentioned, two copies of 75 documents of

wind effects on buildings and structures were transferred to the Philippine

Advisory Committee. This occurred during September 1973. These documents

provide the Committee with a fairly complete library of related documents

from the U.S., the United Kingdom, Japan, Canada and Australia. They

provide a current state-of-the-art on extreme winds. One copy of each

document is on file at the University of Philippines Library and the

School of Engineering Library.

A list of the documents is presented as Appendix C.

Additional document collection activities are underway. This is an ongoing continuous task throughout the life of the project. Two copies

of all additional appropriate wind, socio-economic, structural and codes

and standards related documents will be transferred to the Philippine

Advisory Committee at appropriate times, usually during Philippine

visits

.

Information Transfer to Other Wind Areas

Research developed in the Philippines can be directly applied to

other geographic areas subjected to tropical storms. In addition to

southeast Asia, other wind prone areas include the Indian Ocean countries,

the northern Caribbean Islands, and the southeastern coastal regions of

the United States.

To ensure the transferability of research results it is important

these geographic regions be represented. Effective implementation and

dissemination of the projects research results should be accomplished by

local individuals who have a working knowledge of their country's and

geographic areas housing and climatological conditions. Contacts were

established with individuals from Bangladesh and Jamaica. Dr. Jamilur

Choudhury, Assistant Professor of Civil Engineering, Bangladesh University

of Engineering and Technology is representing the Bay of Bengal countries.

Mr. Alfrico Adams, Partner, Douet, Brown, Adams and Associates, Consulting

26
Engineers, Kingston, Jamaica is representing the northern Caribbean

Islands. These individuals, under contract with NBS, prepared a report

and participated in the international workshop conducted in Manila

during November 14-17, 1973. They identified low-cost housing

trends and design problems, socio-economic considerations, information

gaps concerning structural systems and connection details, design loads

and climatological data.

Appendix D contains the reports prepared by the two consultants.

They are entitled "Low-Cost Housing and Extreme Wind-Related Problems in

Jamaica and the Northern Caribbean Islands" and "Low-Rise/Low-Cost

Housing and Extreme Wind Related Problems in Bangladesh".

In addition, these two reports will be submitted to the National

Technical Information Service (NTIS) library upon final acceptance by

AID.

Socio-Economic and Housing Study

An introductory socio-economic and housing study of geographic

areas subjected to extreme winds — Philippines, Jamaica and Bangladesh —

commenced in FY 74. This topic was first addressed during the International

Manila Workshop conducted in November 1973. The purpose of this task is

to develop an educational document on socio-economic and housing information

about the above three countries. This task is based on performing an economic analysis and synthesizing information from previously documented

research. Inputs to perform this task will include information from the

Bangladesh and Jamaican short term consultants reports, previous NBS

research for AID, university research (domestic and international),

general facts from appropriate embassies and developing country desks,

research reports from relevant developing countries, from the NBS project

team interviews and meetings with members from the participating countries

and other sources.

An initial effort was conducted under an NBS contract with Mr. Stephen

A. Kliment A. I. A. a consulting architect from New York City. His draft

report summarizes information from fourteen documents (see Appendix E)

.

The draft document will be reviewed by NBS and AID to decide its final

format with attention to; the reader audience, textual message, graphic

presentations and tabular layout. After this review the final portions

of this task will be adjusted accordingly.

Directly related to this project is a term requiring clarification

or resolution — i.e. what is a low-cost house? Is it one or two times

the family annual income? No one single, well accepted, definition is

available. Since this project addresses low-cost housing as it relates

to a high technology research activity it is necessary for the reader to

have a better "feel" or appreciation of the term. An initial attempt was made in FY 74 to better acquaint the reader with this term. This is

presented below. During FY 75 an in-depth economic analysis will be

performed including an assessment of — what is a low-cost house.

27
Mr. Sixto L. Roxas III, President, Bancom Development Corporation

delivered a paper titled" Testimony on Low-Cost Housing" before the

Philippine Senate Committee on Housing Urban Development and Resettlement

in January 1969. In his paper, Mr. Roxas presented some economic information which is graphically presented below. His information establishes

a curve based on total family income versus the value of a home and lot

which a family is permitted to purchase at 90 percent financing for 25

years at seven percent interest.^

cc

(U3

rH>

C

•H

VALUE OF HOUSE AND LOT VS. CAPACITY TO PAY

i 1

\ I H

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Annual Family Income (Pesos)

A curve was plotted through the points which approximate the data

given by Mr. Roxas. The curve suggests a family with an annual income

of 2000 pesos can afford a house valued at 1.3 times their annual income

(2,600 pesos) or at an annual income of 3000 pesos the family is entitled

to purchase a home at about 1.8 times their income. Accordingly, data such

as illustrated above could establish a boundary limit for low-cost

housing. Just where along the abcissa is the poverty line (which could

establish the range of low-cost housing) is unknown. However, as a rough guide the above figure provides the reader with a better impression

of the ratio of housing value to family income.

Housing in the Philippines - Preparation Material for the Conference

on Housing , National Economic Development Authority, Philippines,

1973.

Similar information is presented in other documents such as: Housing

Program Pre-Investment Survey for the Philippines , USAID Mission,

Manila, March 1972; and Research Study of the Socio-Economic Aspects of Low-Cost

Housing in the Philippines , Sycip, Gorres, Velayo and Co., Manila,

Philippines, 1972

28
In conjunction with the above, it is important to recognize that

income varies throughout the Philippines (and any country for that

matter). Mr. Roxas provides income information stratified by 1) Manila

metro area, 2) Urban areas other than Manila, and 3) for the entire

country. This information is presented below.

INCOME DISTRIBUTION

50--

Annual Family Income (pesos x 1000)

The figure suggests that families living in urban areas other than

Manila are generally financially better off.

Information from the above figures provide the reader with boundary

constraints leading to the construction of poverty lines and value

limits for low-cost houses.

Philippine Housing Construction Practices

In this section of the report some of the construction practices

employed in residential housing are examined and their implication with

respect to the wind resistant characteristics is considered. The purpose

of this is to indicate areas where improved construction practices could

significantly improve the wind resistant capabilities.

A typical initial construction operation involves excavation of a shallow trench around the perimeter of the site as shown in figure 13.

Since most new houses are constructed on grade without basements the

walls are constructed in the trench. Note however that footings are not

used and the block walls are laid directly on the ground. Although

footings are not needed to compensate for freezing and thawing as in

29
Figure 13 Shallow trench for wall placement
other climates, placement of the block directly on the ground does not

provide an adequate distribution of the wall loads to the soil. High

bearing pressures occur under the block which eventually result in

unequal settlement. Cracking of the walls as a result of this unequal

settlement is a distinct possibility. In addition, this practice does

not provide any resistance to uplift forces, other than the dead weight

of the structure, for resisting overturning by high winds. Although

complete overturning is unlikely, small uplift displacement can result

in cracking of the structure.

Figures 14 and 15 illustrate the quality of the wall construction.

The poor quality mortar joints and irregular nature of small pieces of

block is apparent. In some cases large voids exist in the mortar joints

which severely decreases the strength of the wall. The load distribution

for the reaction from the roof beam shown in fig- 15 is very irregular

resulting in high local stresses. These local stresses cause cracking of the

block, settlement of the pier and very little ability to resist lateral

load

.

Footings are also not used for the corner columns which are major

supporting elements for the roof loads, see figure 16. Minimal uplift

capabilities and settlement problems exist similar to those discussed

for the walls. The lack of a positive connection between the columns

and the block do not provide for lateral load; therefore, the two units

act independently and the stiffening effect of the walls does not exist.

Details of the connection provided between the supporting columns

and the roof members are shown in figures 17, 18, and 19. Minimal

anchorage is provided. The long reinforcing bars (the column will be

cast-in-place later) shown in figure 17 are bent over the roof member as shown in figure 18 and anchored on the other side as shown in figure 19.

This connection provides a very flexible joint which is subject to large

displacements under lateral or uplift loads encountered in high winds.

Lack of positive connection between the corner columns and the

walls discussed previously is also shown in figure 20. Note the considerable length over which concrete is not present.

Framing details for the window openings are shown in figure 21.

The lack of positive attachment between the window frame lintels and the

walls are apparent. The irregular filler blocks and large amounts of

mortar used provide very little strength. In this case wind loads on

the windows would cause the entire window unit including the frame to

blow out.

The weaknesses noted above are not apparent following completion of

the house. As seen in figure 22> application of finish material covers

up these defects. Under wind loading, however, the effects of these

weaknesses show up.

As another example, when tieing the roof material to roof trusses,

minimal connections are usually provided between the roof sheeting and

31
32
gure 17 Column reinforcement anchorage to roof rafters
Figure 19 Roof anchorage detail
Figure 22 Exterior appearance of completed structure

35
the main supporting members as shown

provides a very flexible connection

load. In addition, the eccentric at

beams and localized bending of the r bolt hole. Nailing through the thin

and increases the possibility of its

at some other housing construction p

thin strap. While this is an improv

the torsion problem remains.

in figure 23. The thin strap

subject to large displacments under

tachment causes torsion of the roof

oof sheeting in the vicinity of the

metal strap reduces its strength

tearing under load. It was observed

rojects, a "J" bolt replaced the

ed connection (rigid connection),

Wind damage to similarly constructed houses by Typhoon Yoling

during November 1970 is shown in figures 24 and 2 5. Referring to figure

24, the consequence of the poor mortar joints and lack of bond strength

discussed in figure 14 is apparent. Note that the wall separated from

the corner column (upper left hand portion of fig. 24) due to the lack

of a positive connection and minimal bond between the column and the

wall. Similarly, the window unit completely separated from the wall at

its base and toppled in.

The wall failure shown in figure 2 5 is similar to that in figure 2 4. Note also the uplift of the roof framing at the connection to the support

column. Although complete separation did not occur, the flexible connection detail illustrated in figure 18 permitted substantial displacement.

36
37
Figure 24 Wall damage resulting from Typhoon Yoling, November 1970
B. EXPECTED PROGRESS THROUGH PROJECT COMPLETION

Full-Scale Studies

Full-scale studies will continue during the remainder of the project.

Because of the unique opportunity afforded by these field test sites to obtain information that is not available from any other source, it is

hoped that the Philippine Advisory Committee will continue to operate

these field sites long after completion of the project. This information

can serve as a control on wind tunnel test results and can provide

considerable insight into the long term effects of wind on structures.

An advantage of the test equipment used in this study is that the pressure

transducer positions can be easily changed after a storm to study wind

pressure distributions -on other parts of the test houses, thereby enhancing

the value of the data and reducing the amount of redundant information.

It is hoped that at least one data tape will be generated at each of the

test sites during FY75. However, this depends upon the frequency of

storms and the position of the storm tracks; variables that cannot be

controlled in the experiment.

Wind Tunnel Studies

As indicated earlier, the primary advantage of wind tunnel studies

is that they allow the systematic generation of coefficients required

for design criteria. This assumes, of course, that the model results

can be scaled up to the prototype case. Test results to date indicate

that the coefficients obtained from the models are indeed valid but they

will be checked as more full-scale data become available.

It is anticipated that approximately 10 model configurations will

be investigated during the next year with roof slopes ranging from 0° to 30° and eaves overhangs ranging from 0 to 1.5 meters (full-scale).

Initially, two classes of surface roughness will be used in these studies.

If it becomes obvious that one particular roughness creates a "worst

case" condition, the remainder of the program will be limited to one surface roughness.

Development of Design Pressure Coefficients

The 1970 edition of the National Building Code of Canada (NBC)

provides for risk of occurrence, terrain roughness, height above ground

and building geometry in calculating wind pressures,

p = qC C C . e g P In this expression, q is a reference mean velocity pressure for a given mean recurrence interval, C is an exposure factor which varies with

surface roughness and height above ground, C is a gust effect factor to

provide for surface pressure fluctuations ca§sed by turbulence and

localized flow phenomena, and C is a conventional mean pressure co- efficient. The proper values fBr Cg will be determined from existing

data, full scale wind data and theoretical models of wind speed distributions in typhoons and hurricanes. The coefficients C and C cannot be developed on the basis of any existing theoreticil modeSs and

must be determined experimentally. This will be the primary output of

the wind tunnel test program with the full-scale test results serving as

a control on both the coefficients and final design criteria.

39
In addition to the above, the full-scale structures will allow some conclusions to be drawn concerning their serviceablility and, if sufficiently high wind speeds occur, their ultimate strength characteristics and performance of structural connections.

Socio-Economic Analysis

A continuation of the socio-economic analysis (a description of the

initial attempt is described above) will proceed throughout FY 75. This

analysis will focus primarily on the Philippines (based upon the availability of documentation) and will address the two other geographic areas represented by Bangladesh and Jamaica.

The analysis will consist of a study of related documents from the

NBS and AID libraries, from a data collection activity of related documents from other groups involved in performing similar research, and

data collected from on-site visits to developing countries. The information will be modified, as required, and formatted for input to the final

report.

Computer-Generated Motion Picture Film

A computer program will be developed during the summer of 1974 to

generate motion pictures depicting the time history of wind loading on Philippine test buildings. These pictures will present the building in

various settings and elevations, including a 360° "aerial walk around",

which will enable the observer to view the wind loads on building components

(roof, eaves and walls).

The input information will consist of wind loading data collected

on the test buildings during FY 74 and FY 75. It is envisioned the

graphical display will consist of segmented building sections (corresponding

to the area located at a pressure transducer) presented as a threedimensional view of wind forces (negative or positive) acting on the

building for various wind directions.

This presentation will assist researchers in analyzing wind load

data. Also, the presentation coupled with audio will serve as an educational tool for those interested individuals to view building reactions

to various wind loadings.

Regional Conferences

To ensure effective transfer of project results as previously

mentioned, members from developing countries (users) are working closely

with the NBS team in developing results and transferring them to their

appropriate groups. In addition to advisory committee meetings; conferences and workshops provide a mechanism to transfer information to a larger body of individuals. Such was the purpose of scheduling the

Manila International Workshop during November 1973 (discussed previously).

By late Spring 1975, many of the tasks outlined above will be com- pleted or nearly completed. At this time a regional conference is

expected to be scheduled in Asia to discuss the progress to data. This

meeting will afford the opportunity to members from developing countries

and the NBS to further establish a cross dialogue for suggesting methods

to better structure the final product.

40
It is anticipated that a draft final report will be prepared for

aid's review at the end of FY 75. This report will include all the

above including activities associated with wind risk mapping, identifications of off-the-shelf building component connectors, assessment of

developing countries ability to fabricate building component connectors,

identification and suggested use of selected building connection details

and plans for a final regional conference expected to be held in Jamaica.

The report will also be aimed at two audiences; the professional and the

layman. The AID reviewed draft final report will be discussed and

disseminated to professionals attending a regional conference in Jamaica

during FY 76.

C. FISCAL YEAR 1975 PROJECT SCHEDULE

The following table presents a Summary of the major activities

scheduled for FY 75. The items are presented for illustration purposes

and should not be considered complete or inflexible. As activities are initiated the project schedule may be adjusted accordingly to reflect

appropriate changes.

41
o

o

Q.tn

42
APPENDIX A

MINUTES OF THE lst-6th PHILIPPINE ADVISORY

COMMITTEE MEETINGS

A-1

MINUTES of the 1st MEETING establishing an ADVISORY COMMITTEE

in connection with the research on "DESIGN CRITERIA AND METHODOLOGY FOR CONSTRUCTION OF DEVELOPMENT (Low Cost) BUILDINGS TO

BETTER RESIST TYPHOONS AND HURRICANES" Held on ^7 April 1973

at the Penthouse, Weather Bureau Office, Devel-opmertt Bank Bldg,

Quezon Blvd. Extension, Quezon City

Present: Dr. Richard D. Marshall

Mr. Noel J. Raufaste, Jr.

Gen. Gaudencio V. Tobias

Col. Alejandro R. Kabiling

Col. Alberto R. Sanchez

Lt. Col, Manuel R. Rebueno

Engr. Jose P. Orola

Engr. Mo-desto D. Soriano, Jr.

Engr. Miguel V. Paala

Prof. Angel A. Alejandrino

Dean Auralio T. Juguilon

Prof. Geronimo V. Manahan

Dr. Ernesto G. Tabujara

Engr. Ainbrosio R. Flores

Archt. Cesar H. Concio

Engr. Andres 0. Hizon

Engr. Cesar A. Caliwara

Engr. Rosalio A. Mallonga

Mrs. Magdalena A. Templa

Mr. Romeo G. Cordoba

Mr. Catalino P. Arafiles

Mr. Wellington A. Minoza

Mr, Manuel C. Bonjoc

1:01 The meeting was formally opened by Mr. Arafiles at 2:55 p.m.

After -jelcoming the group to the meeting which was called

to form an Advisory Committee in connection with the research

on "Design Criteria and Methodology for Construction of Development (Low-Cost) Buildings to Better Resist Typhoons and

Hurricanes", the floor was turned over to Dr. Tabujara who

introduced Dr. Richard D. Marshall and Mr. Noel J. Raufaste, Jr.

of the U.S. National Bureau of Standards, Washington, D.C.

Likewise introduced were all those present.

1:02 Mr. Raufaste presented slides showing the organizational

chart, Work Plan, Objectives and Projects of the U.S.

National Bureau of Standards. He also stated that there

will be an international Organizational Meeting in August

or" Septembe\^ 19 73 in Manila. Other countries proposed to

be represented are Bangladesh and Jamaica.

1:03 Engr. Hizon suggested that all information given by Hr,

Raufaste be reproduced. Dr. Tabujara replied that the

University of the Philippines would do so. A few copies

of the reproductions of the slides were distributed.

1:04 Engr. Paala inquired about funding and Mr. Raufaste informed

"the group that no funds are available from the U.S. National

Bureau of Standards.

1:05 Mrs. Templa stated that there must be a formal project

proposal

.

1:05 Dr. Tabujara suggested that the "fund" need not be in the

form of cash but knowledge, paper work, research, equipment

and the like.
Minutes, 1st Meeting - pa^e 2

1:07 Engr. Hizon said that all the results of such efforts should

be printed for publication and made available.

1:08 Dr. Marshall said that although they can offer no monetary

help, they can offer technology, computer services, and

equipment. He also stated that one of the functions of the

NBS is to disseminate all information internationally, to

exchange information and to have free discussions.

1:09 Gen. Tobias suggested that together with the Advisory Comitee, there should be a coordinating committee with an administrative staff and a secretary to do the job,

1:10 Engr. Hizon stated that before the committee can start the

following have to be made available:

a. Materials used and gathered during the UNESCO Seminar.

b. Studies of the Swiss government,

c. and the National Physical Laboratory of England,

d. Studies of Japan,

e. All U.S. studies.

These could be gathered and kept in one agency, such as the

U.P.

1:11 Mr. Marshall informed the group that they will supply some materials and instrumentation particularly coming from the

NBS.

1:12 The following were resolved:

a. Dr. Tabujara was unanimously selected as the Presiding

Chairman of the Advisory Committee.

b. All those present are to be members of the Advisory

Committee as formally formed and any other entities

willing to be of help may also be represented in the

Committee. Those named were NEDA, GSIS, SSS, PHHC, NHC,

LHDC, NSDB, UP, WB, PACE, ASEP, PSA, BPW.

Lt. Col. Rebueno commented that the PHHC need not be a member of the Committee but that they are vjilling to

help, such as having one of their lands as the project

site

.

c. The U.P, will be the depository for all information and

will be in constant contact with the NBS in the U.S.

d. Upon the suggestion of Mrs. Templa a Sub-Committee was

- fcrmed to do the planning of activities of the Advisory

Committee. Gen. Tobias and Dr. Tabujara were unanimously

elected Chairman and Vice-Chairman , respectively. After

deliberation, the members selected were:

Dir. Roman L. Kintanar of the Weather Bureau

Mrs. Magdalena A. Templa of the NSDB

Engr. Ambrosio R. Flores of the Phil. Stan. Assoc,

Engr. Andres C, Hizon of the Assoc. of Struc. Engrs.

of the Philippines.

Upon the request of Gen, Tobias, the appointment of

Col, Kabiling was accepted by Dr. Tabujara. Col.

Kabiling will replace Gen. Tobias in this Sub-Committee.

The first meeting of the Sub-Committee will be on

Friday, May ^i, 1973 at 4:00 p.m. at the Sulo Hotel,

Quezon City.
Minutes, 1st Meeting - page 3

1:13 The Meeting was adjourned at 4:48 p.m. with Dr. Marshall

and Mr. Raufaste thanking the group.

Due to the request of some members of the Committee,

additional slides were presented by Dr. Marshall and

Mr. Raufaste.

Prepared by

:

(Sgd.) Cynthia S. Enriquez

U.P. Building Research Service

NOTED:

(Sgd.) Ernesto G. Tabujara

Executive Officer, U.P.B.R.S.
-1 ^
MINITTES of the 2nd MEETING of the ADVISORY COMMITTEE formed in connection

with the Research on "DESIGN CRITERIA AND METHODOLOGY FOR CONSTRUCTION OF

DEVELOPMENT (Low-Cost) BUILDINGS TO BETTER RESIST TYPHOONS AND HURRICANES".

Held on 9 August 1973 at the Buendia Hall, 5th floor. Bureau of Public

Works, Bonifacio Drive, Port Area, Manila.

Present: Dr. Ernesto G. Tabujara, Presiding

Col. Alejandro R. Kabiling

Col. Alberto R, Sanchez

Col. Manuel R. Rebueno

Engr. Jose P. Orola

Engr, Modesto D. Soriano, Jr. Prof. Angel A. Alejandrino

Prof. Gercnimo V, Manahan

Dr .. Josefina M. Ramos

Engr. Ambrosio R, Flores

Engr. Andres 0. Hizon

Engr. Octavio A. Kalalo

Engr. Rosalie A, Mallonga

Mr. Catalino P. Ar. iCi.lca

2:01 Before the formal start of the meeting:

1. Engr„ Flores staggested that Dean Juinio be designated instead

as Honorary Chaiman of the Advisory Coraraittee, with Dr. Tabujara

as Chairman, This view, which was supported by Engr. Hizon, was accepted by the group.

2. Two (2) members of the Advisory Committee who were unable to

at-':end the 1st Meeting were introduced; namely:

a, D.r- Jcscfine M. Ramc", U.P. Building Research Service, and

b. Engr. Octavio A. Kalalo, President, Association of Structural

Engineers of the Philippines.

3. Prof, Manahan v/as appointed Secretary of the Ccmmittee by Dr. Tabujara.

4« Mr, Arafilss informed the body that the new designation of Dr. Roman L. Kintanar is Administrator of the PaG-ASA (formerly

Weather Bureau) which stands for Philippine Atmospheric Geophysical and Astroncmical Services Administration.

5. All those present were re-introduced.

I

2:02 The meeting formall-/ started at 2:20 p.m„ After a brief introduction, and by iray of inf onn.\ng the members about recent developments

on the research project, Dr„ Tabujara read a memorandum of Dean

Juinio addressed to U.P. Preoident Lopez requesting support for the

proj'sct .from the University, Pres. Lopez has reacted to this project favo:rably, but the members felt that clarifications must be

made regarding the r.anner and extent of this endorsement. Prof.

Manahan and Dr, Tabujara said that a budget proposal for the operations of tho U^P. Bv:'J.d\:Tj Resop.rch Service for next year had

been submitted, Dr- Tabujcx'a c -cured the members that the U.P.BRS

is: able and trilling to coordinate this research project, but stressed

that the full backing of each member of the Advisory Committee, whether by ind-'.viduals or by institutions, is needed.

2:03 Dr. Tabujara referred to the letters ad documents he received from

"Mr. Raufaste, Jr. of the U.S. National Bureau of Standards (NBS) for

discussion, (All pertinent papers were either Xeroxed or mimeographed and a set was provided each member.) Dr. Tabujara canmented

that there were itcips which had to be answered urgently, considering

that the typhoon season Jie.d come,

2:04 For expediency, the Advisory Committee confirmed that constructing

the experimental house at the PAG-ASA' s Science Garden in Quezon

City was most convenient. This recommendation was arrived at during

the discussions of the S\ib-Ccmmittee (of six) held on May 4, 1973.

Quoting from hix, Raufaste's letter, at least three (3) test sites
Mj.nutes. 2nd Meeting - page 2

• r would have to be identified by the Advisory Ccsnmittee, with prefer- rably three (3^^ experimental houses at each site.

Since the Science Garden was chosen to be one of the test sites,

two other sites with different topographic and climatic characte-

. . ristiCB would be selected. The PAG-i^A's station at Virac, Catan-

. '. "duines, was sioggested as one of these, but Dr. Tabujara proposed

that the final selection be deferred until the Advisory Coramittee

could confer with Dr. Marshall and Mr, Raufaste when they ccme to

the Philippines first week of September.

'Z.: 0 5 As suggested by ^ES, at least one exijerimental house must be ready

by the first week of September. To this. Col. Kabiling informed

the group that the National Housing Corporation (NHC) could cons«f

. truct one of their prototypes within two (2) weeks. For the first

test site at the Science Garden, the NHC was requested to put up

two houses and LHDC, represented by Col. Sanchez, would construct

another one. Both Col, Kabiling and Col. Sanchez canmented that

. an "official" letter from the Advisory Committee requesting for

* these donations would be in order. Dr. Tabujara pronised to vftrite these letters.

2:06 For the other te^t sites, Engr. Orola and Engr, Soriano, Jr. of

the GSIS, as well as Col. Rebueno of the PHHC, signified their

desire to convince their respective entities, to provide the rest

of the experimental houses.

2:07 The NHC plans for one house would be picked-up by Dr. Tabujara

from Col. Kabiling the dky after the meeting, and the former

would be responsible in sending these to NBS. The NBS engineers

need the plans in order to program the location of the test instruments .

2:08 Mr. Arafiles also confirmed the commitment by Dr. Kintanar that PaG-ASa personnel could double as observers in the absence of any

other provision as such. These same people could do occasional

maintenance work on the eq uifjaent, too. Col. Rebueno offered to

assign army men as first-class trainees who would also act as guards

at the project site for at least six months. Engr. Kalalo's suggfestion that full-time employees be hired for this project was considered pranature in view of the uncertainty in the funding.

In this connection. Dr. Tabujara stated that some of the profes-ST.

ional organizations might be able to help in terms of logistics,

to which Engr. Kalalo of the ASEP and Engrs. Soriano and Orola of

GSIS gave encouraging answers. Dr. Tabujara answered the direct

question of Col, Sanchez that the house to be constructed by LHDC

may be needed by the beginning of the year,

2:09 An urgent item was the information contained in a cablegram from

Mr, Raufaste, Jr. that full-scale equipment and instrmnentation

are due to arrive in the Philippines by the end of August. These

instruments had been calibrated and tested at the NBS and would

'i therefore be ready to be used upon receipt here.

Col, Sanchez suggested that the US AID, c/o Mr. W. Larson, would

be in a much better position to have the equipment released frooi Clark Air Force Base and consequently these could be turned over

to the Advisory Ccitimittee. A second alternative was to ask for r the help of the U.S. Embassy. If neither of the above was feasible,

Dr, Tabujara said that the Advisory Coramittee could request for

the help of Pres. Lopez of the U.P.

2:10 Two lists of equipment were read:

Those instruments which pertain to the experimental house, and those

coniiected with the wind tunnel instrumentation for the U.P. Hydraulics Laboratory. Prof. Alejandrino commented that tfee wind tunnel

at the U.P. has a size of 4 feet by 4 feet, Engr, H^zon inquired
Minutes. 2nd Meeting - page 3

whether the 14-track analog tape recorder could be used directly

with the present ccmputer set-ups locally, as for example, the

one at the U.P. Ccxnputer Center. Prof. Alejandrino replied that

at the start of the research, the tapes would be transcribed at Washington, D.C*, but expressed hopes that a converter may be

provided by NBS to enable these tapes to be processed locally

in the near future.

2:11 Er^r. Kalalo was appointed the PRO for the project. Dr. Tabujara

accepted the responsibility of pr^Daring the first write-up which

Eixrr. Kalalo would publicized,

2s 12 Due to organizational difficulties, stated by Mr. Raufaste, Jr.,

the Advisory Committee welcomed the postponement of the Organizational Seminar until mid-November. Countries to be represented

are the Philippines, Bangladesh and Jamaica, but representatives

fran Hongkong, Japan and other countries be invited also. The

adyiaory Committee ciccepted the offer of Mrs. Templa of NSDB for

the use of the NSDB Auditoriimi at Bicutan for this Seminar. Hotel

Intercontinental at Makati was cited as convenient for foriegn

attendees

.

2:13 The NBS confirmed that they would provide assistance on the following: Secretariat, Documentation and Printing, international

travel, while the AdvieEory Committee's responsibility would in-""' elude: Program, Arrangements (including local trcinsportat ion, if

needed) and Refreshments. Dr. Tabujara appointed the following

chairmen:

a. Finance - Mrs. '^cTp.la

b. Arrangements - Engr. Orola and Engr. Soriano, Jr.

c. Program, Invitation and Publicity - Engr. Kalalo

d. Reception and Hospitality - Archt. Concio

e. Editorial - Engr. Flores and Dr. Ramos

Each chairman was requested to choose his members and the /idvisory

Committee will function as the Executive Committee.

2:14 Dr„ Marshall and Mr. Raufaste, Jr. wrote Lhat they would be in

Manila about the first week of September. They also signified

their desire to visit the PAG-i^A's weather station at Virac,

Catanduanes. It was suggested that the US hID be alerted of this

plan so that they could help in the arrangements. Col. Rebueno

volunteered to acccanpany the two gentlemen, in addition to PhGASa's personnel.

2:15 Before the meeting was adjourned. Dr. Tabujara announced the

recent promotion of Engr, Mallonga as Regional Director of the

Fourth Regional Office of the BPW. In behalf of the Advisory

Ccmmittee, Dr. Tabujara thanked the BFW through Engr. Mallonga

for hosting this Second Meeting.

2:16 The meeting was adjourned at 4:00 p.m. and the Advisory Ccmmittee

would reconvene sometime first week of September.

(Sgd. ) GERONIMO V. MANAHaN

Secretary

EGT:cse

KINUTES of the 3rd MEETING of the hDVISORY COf-iMITTEE formed in connection

with the Research on "DESIGN CRITERIA AND MTHODOLOGY FOR THE CONSTRUCTION OF

DEVELOPMENT (Low-Cost) BUILDINGS TO BETTER RESIST TYPHOONS AND HURRICANES,"

Held on 14 Septemoer 1973 at the Housing Operations Center, 3rd floor.

People's Honesite and Housing Corp., Quezon City

Present: Dr. Ernesto G. Tabujara, Presiding

Col. Alejandro R. Kabiling

Col. Manuel R. Rebueno

Engr. Modesto D. Soriano, Jr.

Aditi. Reman L. Kintanar

Prof. Geronimo V. Manahan

Dr. Josefina K. Ramos

Engr. itobrosio R, Flores

Archt, Cesar H. Concio

Engr. Andres 0. Hizon

Mrs. Magdalena A. Templa

Mr, Catalino P. Araf iles

Dr. Richard D. Marshall

Mr. Noel J. Raufaste, Jr. Engr. Jaime C. Cano

3:01 The meeting started at 1:15 p.m. Dr. Tabujara introduced Engr.

Jdime C. Cano of the NHC to the other members of the Advis«ry Committee, In view of the power lincertainty due to scheduled Meralco

brownouts. Col, Rebueno suggested that the order of business be

changed to enable Dr. Marshall and Mr. Raufaste to show slides.

3:02 Mr. Raufaste took the floor and reviewed the activities which transpired since the organizational meeting of the Advisory Ccanmittee last

April. A more comprehensivo three-year schedule of activities was presented with emphasis on the conduct and format of the final draft

of the report so that the members could be oriented to the general

aims and purposes of the project. Field experimentation and wind

tunnel phases of the project were clearly defined. The former phase

called for seven (7) experimental houses to be constructed at three

(3) different test sites within the first year.. Mr,: Raufaste >aiso

showed slides of houses which were proposed for Bangladesh and also

for the Carribean area. One type for Bangladesh, proposed and designed by CaRE, coste about $1.10 per sq. ft. of area.

^:03 Dr. Marshall showed slides of the various equifanent and related

instrumentation which will be used in this research. He also ex- plained that preliminary wind tunnel tests have been conducted

abroad with the view of continuing these experiments here at tho

National Hydraulics Center Laboratory. The Advisory Committee was informed that all equipment and accessories necessary to fully instrument one experimental house have been delivered to the Pag-asa's

Science Garden, Because of their rather critical and busy schedules,

- Mr. Raufaste and Dr. Marshall expressed hope that the NHC, under the

direct and personal supervision of Col. Kabiling, would be able to

put up the first experimental house by Tuesday or V/ednesday of the

following week. This would enable Dr. l-krshall to personally supervise the installation of necessary equipnent before he leaves on Sept. 24. Col. Kabiling confirmed that the house will be ready for

the installa-^.ion of sensors and other instrimients by Wednesday or Thursday.

3:04 In answer to Mr. Raufaste's question. Dr. Tabujara changed the designation of Engr. Kalalo to Publicity Chairman instead of Piiblic

Relations Officer. Engr. Hizon accepted to become member of this

important S\±)-committee

.

3:05 Dr. Marshall further stated that the Wind Tunnel at the National

Hydraulics Center Laboratory will perform the wind tunnel tests which

will cauplement whatever tests had been djne abroad. The NBS will
hinutes, 3rd Meeting - page

assist in the modeling techniques and will provide other expertise

necessary in order to verify certain findings from the field data.

3:06 Engr. Soriano reiterated G3IS' willingness to donate two (2) houses,

possibly the 5th and the 6th house in the program, within the Diliman

area.

3:07 Mr, Raufaste described the objectives and the proposed conduct of the

November 1973 Workshop, as follows:

A. During the Workshop:

1. To discuss socio-economic considerations (per geographic

area) as they affect the design and acceptance of buildings.

2. To discuss information gaps concerning structural systems and

connection details.

3. To discuss wind design load requirements.

4. To discuss climatological data needs.

B. ImTL.diately after the VJorl;shop:

', 1. Prepare report on the above.

2. Elaborate on problems associated with extreme wind loading.

C. Short-term international consultants are requested to:

1. Identify housing trends and their design problans.

2. Discuss the influence of socio-economic considerations on housing patterns.

3. Perform a survey and analysis of housing needs for the next

10 years.

4. Collect and tabulate available climatogical data on extreme

winds.

5. Collect and tabulate wind damage statistics.

6. Study the probability of alternative solutions in mitigating

, losses due to high v;inds.

- 7. Define possible low-cost dwelling design problem areas unique

to each consultant's geographic area.

3:08 Instead of being co-chairmen of the Editorial Sub-canmittee, Engr,

Flores and Dr. Ramos were re-designated co-chairmen of the Technical

Papers Sub-oommittee . The Technical Papers Sub-committee will meet

together with Mr. Raufaste, and possibly Dr. Tabujara, on Thursday,

Sept. 20, 1973. This Sub-committee will have the responsibility of

gathering all technical papers, and reviewing each of them prior to

forwarding these to the NBS for final review. It was tentatively

suggested that:

1. Dr. Marshall would take care of presenting papers correspoiading

to Items A and B of the tentative program. Prof. Alejandrino

would be requested to contribute on this particularly with re- gards to the National Hydraulics Center Laboratory's capability

to support this research program.

2. Prof. Manahan would help out in Item C-1, and the name of Dr. Mary R. Hollnsteiner, Director of the Institute of Philippine

Culture, was also mentioned,

3. Engr. Flores and Archt. Concio would discxiss Item D, while

Prof, de Castro of the U.P. College of Engineering would be

able to help in Item B. Pag-asa would discuss Item A-1.

4. Mr. Raufaste would give the suggested format for the technical

papers before he leaves Friday of the following week.

5. Mr, Raufaste informed the group that the foreign participants may

present papers pertaining to their respective experiences,

3:09 It was decided that the Workshop will be for three-and-a-half (3^)

days. The dates November 14 thru 17, 1973 were selected, and the . Workshop will be held at the Paulino J. Garcia Memorial Hall, NSDB,

Taft Avenue corner Herran, in Manila instead of at Bicutan as previously recorded. Mrs. Tanpla immediately offered to make the necessary reservations for the place.
Minutes. 3rd Meeting - page 3

As Chaiman of the Finance Sub-committee, Mrs. Templa selected Dr. Tabujara as Co-Chairman with the following as members: Col. Kabiling,

Engr. Paala, Engr. Soriano and Engr. Orola. The Finance Sub-committee

was scheduled to convene in a luncheon meeting at Sulo Hotel, Q»Clj

Wednesday, Sept. 19. Mrs. Templa also volunteered to be member of

the Sub-committee on Program, Invitation and Publicity, chairmaned

by Engr. Kalalo.

3:10 Archt. Concio accepted his appointment as Chairman of the Reception

and Hospitality Sub-committee.

3:11 Mr. Raufaste suggested Dir. Niblock of US AID as a probable speaker

to deliver the Welcome Address during the Workshop. Other names suggested for the welcome ceremonies were Dean Alfredo L. Juinio as Honorary Chairman of the Advisory Committee, and other high government officials.

3:12 In the selection of the second test site, the Advisory Committee

heard the arguments for and against the selection of Virac, Catanduanes. Adm. Kintanar and Mr. Arafiles described the conditions at their new weather station at Daet, Cam. Nortec

1. Dr. Marshall favored the latter considering the problems in the

wind tunnel simulation of the actual site topology and other

conditions.

2. The logistics problem tend to favor Daet over Virac.

3. The presence of ccinmercial electrical power at Daet makes experimentation more reliable, particularly during typhoons.

4. Both sites are serviced by airstrips although D-.e.t could' be. reached

by -land, whereas Virac could notj

5. The slight edge in the frequency of typhoons at Virac as compared

to Daet was not considered too significant.

Tentatively, the Advisory Committee preferred Daet pending the report

of Dr. Marshall and Mr. Raufaste after their visit there next week.

For Site No. 3 the Weather Stattion at Infanta, Quezon and at Baguio

were mentioned.

3:13 Dr. Marshall raised the question of whether the Advisory Committee

preferred to start the second test site or to expand the present

Science Garden site to include two houses by this coming November,

The idea was to report back to Washington, D.C. so that pertinent

sets of equipment could be prepared and these could be brought here

by Mr. Raufaste and Dr. Marshall during their next visit in November.

After some discussion, it was decided that a second experimental

house at the present first site (Science Garden) would offer more

advantages and would be expedient. Dr. Tabujara felt that another

type of house must be provided, and the IHDC would be requested to

donate this one.

3:14 Mr. Raufaste distributed copies of "Bibliography - Wind Effects on Buildings and Structures." He also informed the Advisory Committee

that Dr. Marshall and he brought with them some 50 lbs. of documents

which they wish to be entrusted to the U.P, College of Engineering

library as agreed upon during the April meeting. These documents

will be made available to the members of the Advisory Committee.

In the meantime Prof. Manahan promised to reproduce the Bibliography

for those who would be interested.

3:15 Mr. Raufaste also advised the members to prepare a list of publications not readily available here which may be of interest; particuslarly as they pertain to the current research project. The NBS,he

said, will try to get these or will suggest the source where said

documents may be procured.
Minutes. 3rd Meeting - page 4

8:16 Engr. Hizon was designated to draft a Letter of Acceptance which would

serve as the official transfer of eguipment and instrvunents donated

by the NBS to the Philippine government through the Advisory Conimittee.

The Pag-asa will be the depository for the field instrumentation and

equipnent, while the hydraulic equipanent will be entrusted to the

National Hydraulics Center,

3:17 Finally, the Minutes of the two previous Meetings of the Advisory

Committee were (officially) approved as corrected,

3:18 Before adjournment. Dr. Tabujara expressed thanks to the PHHG,

through Col. Rebueno, for hosting this third meeting. The meeting

was adjourned at 4:00 p.m.

(Sgd.) GER0NII4O V. MANaHAN

Secretary

(Sgd, ) ERNESTO G. TaBUJaJRA Chairman

Prepared By:

(Sgd.) Cynthia Senoran Enriquez
MiNUTESc of the 4th MEETING of the ABVISCS?Y COMMITTEE formed in connect-

.

ion with the Research on "DEVELOPMENT OF DESIGN CRITERm AND METHODOUDGY

FOR IXfW-RISE/LOW-COST BUILDINGS TO BETTER RESIST EXTREME WINDS."

Held on 13 November 1973 at the Penthouse, SSS Building,. East Avenue^

Quezon Cj^ty, '~

.

Presefvt: Dr. Ernesto G. Tabujara, Presiding

Gol, Alberto R. Sanchez

^

Col, Manuel R. Rebueno . Engr, Jose P. Orola

Engr, Modesto D. Soriano, Jr.. Engr. Miguel V, Paala

•Prof. Angel A, Alejandriho

Dean Aurelio T. Juguilon

Dr. Josefina M. Ramos

EnQT, Arabrosio R. Flores •

,^ Engr, Andres 0. Hizon

Engr. Cesar A. Caliwafa . . Engr. Rosalio A. Mallonga

Mrs, Magdalena A. Templa

Mr, Catalino P. Arafiles

Mr. Wellington A, Miftoza

' Prof, Geronimo V, Manahan

Archt, Heminio Golfo

Archt,. Avelino de Veyra •

Mr. Noel ^J. Raufaste, Jr.

Dr. Richard D. Marshrill -

. Mr. William Littlewood

Dt. Edward 0. Pfrang

4:01 The meeting was called to order at 2:00 p.m. by Dr. Tabujara;

r The Minutes of the 3rd meeting were read and approved unanimously,

, He informed the body that since luncheon cannot be served at the

NSIB Hall, the Workshop participants will have to profceed to the

Alta Vista Buffeteria -at the Cultural Center, for the duration

of the Workshop, Luncheon will be served there courtesy of various

dp>onsors. The proolem regarding the transportation created by

the gas shortage was discussed,

-4:02 Dr, Tabujara reported that 7 messengers are at the mfeae;nit delivering

the prpgjwms and invitations. ' Mimeographed invitations were sent

> . a few days earlier, aind upon the suggestion of Engr, Hizon, telephone follow-ups were made. A total of 174 persons were invited

although quite a number of them were courtesy invitations.

4;03 Dr, Tabujara ccratiended. the Arrangements Sub-conimittee for a job

well done, Engr. >Iallonga informed the body that he bought two

flags, that of Jamaica and Bangladesh, the rest were borrowed.

Engr, Soriano stated that thq streamers, signs and electric

.fans were all ready.
Minutes. 4th Meetiivcr «» page 2

4:04 For the Reception and Hospitality Sub-Ccinmittee, Dr. Ramos reported that the name plates, plastic Jackets and lunoh tioksts

were ready. Ten iisherettes under the charge of Prof, Manahan

and Mrs, C. Enriquez will assist in the Workshop,

4:05 Col. Rebueno reported that there would be 2 NSDB Secxirity guards

in the premises during the deliberations although, he believed

that this arrangement was not necessary,

4:06 Mrs. Templa stated that the Finance Subcommittee should have

been ohairmaned by Dr. Tabujara, since he did all the work of

getting sponsors. She, however, premised to see what the HSDB

oould contribute as soon aa Dr, Tabujara submits his finalized

draft of proposal for project funding,

4:07 For the program. Invitation and Publicity Sub-Committee, Dr. ^ Tabujara reported that the undertakizig has been widely publicized so much so that people were calling and asking if they ::v could attend the Workshop, The body decided that should there

be future callers it would be alright to tell them to attend.

4:08 Prof, Alejandrino together with Mr. Raufaste would coordinate the

sessions and distribute the audience for the Workshop Sessions.

4:09 Dr. Tabujara reported that Marsteel Corp, would sponsor one

luncheon, and specifically requested that no co-sponsor would be

' necessary. He announced the other sponsors namely: Weldon

Construct ioa Corp., Asso, of Structural Engineers of the Phils,,

National Society for Seismology and Earthquake Engineering of

the Phils,, Phil. Aaso, of Civil Engineers, Engr, Cesar A,

Caliwara, Engr, Romeo S, Caparros, Engr. Octavio A. Kalalo, Dr.

Fiorello R. Estuar, Engr. Lauro M. Cruz and Engr. Aitgel Lazaro,Jr.

Ewr» Soriano also solicited f>5, 000.00 from the GSIS and P2,000,00

frcm Philrock Products Inc. Dr. Tabujara suggested that the Advisory Committee should elect a Treasurer, At this point, he

welcomed Mr. Mifioza who just arrived from the U.S.A.

4:10 Col. Sanchez reported that there would be a Metrocom escort for

the visit to the experimental house at the Science Garden of the

PAfiASA. He also informed the gro\ip that the second experimental

house which the LHDC contracted to the NHC was delayed due to the

gas shortage, but that he would follow-up its completion so Dr.

» Marshall could start the instrumentation by Monday, Hovember 19i

4:11 Mr. Raufaste commented that they were very impressed with everything. H& then summarized the activities for the next 2 years

with the aid of Xerox copies which he distributed. The project

started last March 1973; late April 1973 Dr. Marshall and Mr,

Raufaste came here and the Phil, Advisory CoBmittee was formed.
Minutes. 4th J'^etina - page 3

Their second visit was last Septouber when the first house was instrmented and now they would be ready to instrument the second

experimental house. The object was to instrument 7 full-scale

houses at 3 independent test sites which would relate to 7 wind

tunnel scaled-down buildings at U.P,

4:12 'The floor was opened for discussion of the third site. Considerations given by Dr. Marshall are frequency of wind effects,

logistics and maintenance of equipment. He suggested areas North-east of Luzon. Mr. Raufaste also added that these sites

should be statiscally independent of each other, should represent

different terrain conditions and should be very hilly. He also

reported that during their last visit they were able to make a trip to Daet and take scxne photographs thru the help of U.S. AID.

If the body could decide on the 3rd site Dr. Pfrang and Mr, Noel

Raufaste would make arrangements with the U.S. AID to visit it.

Infanta., in Quezon, Daet and Sto, Tomas in Baguio were named but

due to availability of transportation, manpower and commercial

power, Sto. Tcmas, Baguio was chosen, Sto, Tomas, Baguio according to Mr, Arafiles is 7,000 feet above sea level and has the same frequency of typhoons as Infanta.

4:13 Dr. Marshall stated that the 3rd house's roof should either be

flat, gabled or hipped. If it would be gabled the degree of

inclination should be detennined, if hipped, the length of the eaves should be from 0 feet to 5 feet. The materials to be used

could be asbestos and the truss, wooden with G.I. sheets. According to Dr, Tabujara the usual pitch locally is 1:4.

4:14 It was confirmed by Col. Rebueno that the 3rd and 4th houses to

be build before April 15, 1974 would be donated by the PHHC. In

accordance to the Minutes of the 3rd Meeting, the 5th and 6th

houses would be donated by the GSIS. The 7th house would be from

• CARE of Bangladpsh.

4:15 Mr, Raufaste commended the two or three PAGASA personnel now manning the experimental house at the Science Garden. He inquired

if they could be made use of again for future houses. Mr. Arafiles

added that the three could train other personnel and could assist

at future test sites.

4:16 Dr, Tabujara, on the other hand, canmended the NHC for putting

up the first experimental house in 3 days' time.

4:17 Dr. Marshall informed the body that enough information was gathered during the last 3 typhoons here and that assimilation

could now start. As work evaluation continues at the Colorado

State University we will know how to make the right approach

with the U.P. wind tunnel facilities. Taking data from a 6' x 6'

wind tunnel and modifying or applying these to a 4' x 4' wind
Minutes. 4th Meatina - page 4

tAinnel i*' essential. Hopefully we can use direct geometric scaling

on this and get the tunnel and related equipment into operation

before Dr. Marshall leaves on December 1, 1973, The final series

of wind tunnel testing will hopefully yield the specific needs

for the design criteria,

4:18 Prof, Alejandrino stated that although this is the first time the

National Hydraulics Research Center will deal with a wind tunnel

project, he is very optimistic especially since the Center em- ploys 3 Research Engineers.

4:19 Dr. Marshall stated that he has some more documents with him and

Equipment like the Wind tunnel hot-wired animooeters for measuring . turbulance, pitot tubes for measuring wind dynamic pressures,

recorders and digital analog analyzer - all of which will go to

the U.P. HRC.

4:20 Engr, Hizon ev^gested that the wind tunnel results be= available

to interested parties even before its formal piiblication. A

status report is well in line with this,

4:21 Dr, Tabujara has one set of the documents brought by Dr. Marshall

and this set was reviewed by the 3 Research Engineers, Another

set is at the U.P. Library. He expressed his thanka to the SSS

thru Eingr, Paala for hosting the meeting and to GSIS for hosting

a Sub-Conmittee meeting.

4:22 Mr, Littlewood and Dr, Pfrang expressed their appreciation and

support and wished the project success,

4:23 Dr, Tabujara in return thanked the f©S for its support and expressed his opinion that this project will benefit the Filipinos

more than anybody else. He announced that Dr, Kintanar received

a Presidential award as one of the most outstanding scientists

of the country. It was agreed that Dr, Tabujara would call Mrs.

Templa for the services of a professional secretariat for the

Workshop.

4:24 It was announced by Mr, Raufaste, Jr. that due to unforseen circumstances the following foreign participants could not come:

Mr, Samuel Kramer, Mx, John Gipson, Prof, Sean Mackey, Dr, R,W.R.

Munoey and Dr, Sudhindra Nath Senn.

Dr, Pfrang would take the place of I-lr, Kramer and Dr, Eaton would

then take the place of Dr, Pfrang, Thus, Dr, Eaton would be in

Session B and Dr. Pfjrang in Session D on Friday,

4:25 There will be cocktails on Saturday evening in honor of the foreign

delegates.
Minutes. 4th Meeting - page 6

4:26 Mr, Raufaste wants copies of the Minutes of Meetings. This can be done except for the Sub-Coraraittee Meetings which has no re- corded Minutes since these were all informal meetings,

4:27 Upon the suggestion of Mr, Raufaste the Letter of Acceptance

for the equipment would be made at the end of the project so

that it would be in lump sum, however, temporary receipts, if

possible would be appreciated. The Advisory Committee would

accept the equipanent and the PAGASa would be its custodian,

4:28 The meeting was adjourned at 4:10 p.m.

(Sgd,) GERONIMO V. MANAHAN

Secretary

(Sgd.) ERNESTO G, TABUJARA, Ph.D.

Chairman

Prepared By:

(Sgd.) Cynthia S. Enriquez

MINUTES of the 5th MEETING of the ADVISORY COMMITTEE formed in cc«\nection

with the Research on "DESIGN CRITERIA AND METHODOLOGY FOR THE CONSTRUCTION OF LOW-COST/LOW-RISE BUILDINGS TO BETTER RESIST EXTREME WINDS."

Held on 18 March 1974 at the Seminar Room, 4th floor, Melchor Hall, University of the Philippines, Diliman, Quezon City.

Present: Dr. Ernesto G. Tabujara, Presiding

Engr. Cesar A. Caliwara

Mr, Manuel C. Bonjoc

Engr. Ambrosio R. Flores

Engr. nndres 0. Hizon

Dean Aurelio T. Juguilon

Engr. Rosalio A. Mallonga

Dr. Josefina M. Ramos

Col. Manuel R. Rebueno

Engr. Modesto D. Soriano, Jr. Dr. Francisco Tamolang

Col. Ale jandro R. Kabiling

Dr. Richard^ D. Marshall

Mr. Noel J. Raufaste, Jr. Mr. Peter Paul Castro

5:01 Dr. Tabujara opened the meeting at 2:00 p.m. He stated that most

of the members would not be able to attend due to the short notice

given. Dr. Francisco Tamolang, Commissioner of FORPRIDECOM and a new member of the Committee was introduced to the group.

8:02 A 10-second silence was observed for the late Mrs. Magdalena A. Templa.

8; 03 Dr. Tabujara reported on the status of the 2 houses to be ereoted

at Laoag and Daet. Since the donors, GSIS and PHHC, are governed

by their respective Boards, their approval had to be obtained

first. GSIS, presently have the materials for the 2 houses at the

Laoag site. Although one of the NHC's truck wae burned while delivering some materials, Engr. Soriano and Col. Kabiling are cptimistic that they will beat the schedule for the instrumentation

of Dr. Marshall

„

5:04 It was decided that Engr. Soriano and Mr. Bonjoc will verify the

exact locations of the 2 houses being erected at Laoag since the

cables to be used were pre-cut at 50 meters each. It was also

decided that since PAGASA personnel were to man the houses, one house at least had to be erected at the PaGASa site. The PaGASA

site was found not big enough to hold 2 houses at its ccmpund,

making it necessary to ask the CAA to have the other house at

its compound v/hich is adjacent to the PAGiiSA's, Dr. Tabujara

would have to get Gen. Singson's permission for this.

S:05 The instruments have to be at an air-conditioned roan and since

Mr. Bonjoc stated that there was no air-conditioned room at the

PaGaSa in Laoag, Mr„ Raufaste expressed his opinion of either

getting an air-conditioning unit or asking the CAA if they have

an air-conditioned room at the Laoag CAA Building.

S:06 Dean Jiaguilon stated that he would be going to Laoag on Thursday,

March 21, and so he would be furnished with Dr. Marshall's letter

of instructions to enable the Dean to verify the locations of the

experimental houses and confer with PAGaSa's Mr. Gabuat and Mr. Teofilo Aquino of GSIS.

3:07 Mr. Bonjoc reiterated the permission granted by Adm. Kintanar

for PAGASA personnel to instrument the houses at Daet. The PHHC

Board approved the putting-up of 2 houses at Daet, however, due

to funding problems. Manager Sebastian Santiago decided to include this as part of the housing program planned for Naga which

will take sometime before implementation.
Minutes. 5th Meeting - page 2

5:08 Col. Rebueno reported that Archt. Fernando of PHHC designed 2 houses of 39 sq. mts . each but due to logistic problems he advised Dr. Tabujara to talk with Acting i'ianager Venago.

5:09 Mr. Raufaste's schedule was as follows:

March 20 at Daet

22 back to Manila

26 at the wind tunnel

27 at Laoag

30 back to hanila

April 1 leave for Japan

S:10 Messrs. Dapul and Purisima would go with Mr. Raufaste to Daet.

Mr. Bonjoc has wired the PAGASA in Daet regarding their arrival.

Engr. Soriano will also be there on March 2 8 to 29.

5:11 CilRE, thru its Philippine representative, Mr. Manuel Torres, reiterated their canmitment for 1 house which will be the property

of the Committee.

5:12 Dr. Tabujara reported on the financial status of the Committee,

(Please see attached Financial Report),

5:13 hi. Raufaste turned-over to the Committee 2 books entitled "Design,

Siting and Construction of Low-Cost Housing and Ccatimunity Buildings

to Better Viithstand Earthquakes and Windstorms".

S:14 Dr. Tabujara reported that these will be included with the other

documents already at the U.P. Engineering Library. Another set was with him and could be availed of by the members of the Committee or any other interested party.

S:15 Dean Juguilon could make arrangements for Mr. Raufaste to tour

sane parts of the country and take pictures of typical Filipino

dwellings.

S-16 Mr, Raufaste distributed copies of the Draft Reccanmendations of

the International Workshop held last November 1973. The members

of the Committee were to submit their own comments based on this

draft and submit the same to Engr. Flores, Dr. Ramos and Prof,

Manahan before April 1, 1974. It would then take 3 months for

the NBS to review and print the final recommendations.

S:17 The meeting was adjourned at 4:00 p.m.

(Sgd.) GERONIMO V. I^lNAHA-N Secretary

(Sgd.) ERNESTO G. TaBUJARA

Chairman

Prepared By:
MINUTES of the 6th MEETING of the ADVISORY COMMITTEE formed in connection

with the Research on "DEVELOPMENT OF DESIGN CRITERIA AND METHODOLOGY FOR

LOW-RISE/LOW-COST BUILDINGS TO BETTER RESIST EXTREME WINDS."

Held on 1 April 1974 at the 4th floor, Melchor Hall, University of the

Philippines, Diliman, Quezon City.

Present: Dr. Ernesto G. Tabujara, Presiding

Dean Aurelio T. Juguilon

Dir. Angel A. Alejandrino

Mr, Manuel C. Bonjoc

Mr. Catalino P. Arafiles

• Engr. Modesto D. Soriano, Jr.

Prof. Geronimo V . Manahan

Dr. Richard D. Marshall , Mr, Noel J. Raufaste, Jr.

Engr. Jaime Cano

Mr. Rod Dapul

Mr, Peter Paul Castro

Mr, Enrico Gregorio

6:01 The meeting started at 2:15 p,m, with Dr. Tabujara introducing

Mr, Rod Dapul, technician of the PAGASA v^o together with Mr.

Ignacio Purisima worked very closely with Dr. Marshall and Mr,

Raufaste. These two PAGASA personnel will instrument the re- maining 3 test houses. They went to Laoag with Dr, Marshall

and Mr. Raufaste and with additional instructions could instrument the houses. Mr. Kaufaste was all praises for the two

and he also expressed his appreciation to Messrs. Arafiles and

Bonjoc and the PAGASA.

6:02 Likewise introduced was Engr. Jaime Cano of the NHC. Engr.

Cano assured the body that he would check on the materials used

for the GSIS houses at Laoag, He would also talk with Col,

Kabiling regarding the painting and floor tiles of the houses

at the Science Gc rden.

6:03 Mr. Raufaste reported that they visited Daet and Laoag. They

were able to instrument the PAGASA house at Daet which is a one-storey building made of concrete hollow blocks, G.I. sheet

roofing, wooden trusses and a hip-roof. It also has an airconditioned room which is essential for the instruments. Mr,

Raufaste expressed their optimisim regarding the construction

of the second house at Daet by PHHC.

6:04 On the Laoag site, Mr. Raufaste reported that the CAa building

is actually the PAL Building. One test house is already up

and instrumented and the second test house is under construction.

The 2 houses are oriented at 90% to each other. The second house

is within the CAA Compound. Mr. Raufaste informed the group that

the CAA should be informed of cables placed 6 inches beneath the

ground and runs from the tower to tapt hovise No, 1 since a road

will be constructed here in the near future. He also mentioned
Minutes, 6th ^^etina - page 2

that one air-conditioning unit is needed for the test house.

6:05 Mr. Arafiles reported that there is no water nor toilet facilities

at the Laoag test house. To this, Engr. Soriano replied that

the plumbing fixtures are already at the site and only the spetic

tank is needed. Engr. Soriano also stated that the ^0,000.00

donation of the GSIS is not sufficient for the two houses and he

had to get some of the materials. Dr. Tabujara informed Engr,

Soriano that since the Cotimittee has some money, this could be

used for things like this,

6:06 Mr. Raufaste stated that the CAEffi house is now in Manila according to CARE representative Manuel Torres, Dr. Tabujara read

Mr. Torres' letter giving U.P. full ownership and responsibility

I of the Care house. Dr. Tabujara would reply that ownership

would be to the Philippine government and the custodian will be

the Phil. Advisory Committee.

6:07 Dr. Marshall reported that field studies covered 807o of his time

and that 2 units were already instrumented. Although they had

some equipment problems for the VJind Tunnel facilities, the people there can now carry on with constant ccamuunication between

them. He also expressed his desire for a bigger model than the

present 1:80 scale. He expressed his appreciation for the time

and money spent by the University and made mention of the airconditioning unit supplied for the wind tunnel instruments,

6:08 Dr. Tabujara coraraended the 2 graduate engineers assigned to the

'Wind tunnel project, namely Peter Paul Castro and Enrico Grogorlo.

Dr. Tabujara stated that Dean JuguiIon's report on Laoag would be

put into record and he expressed his appreciation for the Dean's

help.

6:09. Dr. Marshall would probably be back on July or August 1974. Mr.

Raufaste' s telepiione number is 301-921-3233 or 34 and Dr. Marshall's

301-921-3475. For emergencies they could be contacted "collect".

Mr, Raufaste stated that any material, infomation or plan of

typical Filipino houses that the Committee could give him would

be highly appreciated. He also caranented how impressed he is on

the Philippines.

I
Minutes, 6th Meeting - page 3

6:10 Engr, Soriano, on the other hand, commented on how impressed he

was on Mr, Raufaste and Dr. Marshall who worked very hard on instrumenting the two houses at Laoag, Mr, Raufaste then re- ported on how he even had to hold the plane at Clark Air Base

for the instruments could not be located prior to their departure for Laoag,

6:11 Dr. Tabujara thanked Engr, Soriano for all his help. The

meeting was adjourned at 4:15 p.m. with Mr, Raufaste reminding

the body of their ccxnments based on the draft recommendations

distributed during the last meeting.

(Sgd.) GERONIMO V. MANAHAN

Secretary

Prepared By:

(Sgd.) Cynthia S. Enriquez

APPENDIX B

"SIMULATION OF ATMOSPHERE FLOWS IN SHORT

WIND TUNNEL TEST SECTION"

B-1

/

SIMULATION OF ATMOSPHERIC FLOWS

IN SHORT WIND TUNNEL TEST SECTIONS

by

J. A. Peterka* and J. E. Cermak

for

Center for Building Technology, lAT

National Bureau of Standards

Washington, D.C. 20234

Fluid Mechanics Program

Fluid Dynamics and Diffusion Laboratory

Department of Civil Engineering

Colorado State University

Fort Collins, Colorado

June, 1974

Assistant Professor

Professor-in-Charge , Fluid Mechanics Prograia

CER73-74JAP-JEC32
TABLE OF CONTENTS

Chapter Page

ACKNOWLEDGMENTS iii

LIST OF FIGURES iv

LIST OF SYMBOLS v

i, INTRODUCTION 1 1.1 Scope of Study 1 1.2 Review of Previous Modeling Techniques ... 2

II. WIND SIMULATION FACILITIES 6

2.1 Wind Tunnel 6

1 2.2 Spire and Roughness Arrays "... 6

, 2.3 Instrumentation and Data Acquisition .... 7

III. RESULTS 9

3.1 Mean Velocity 9

3.2 Turbulence Intensity and Shear Stress ... 12

3.3 Correlations, Integral Scales, and Spectra . 14

IV. CONCLUSIONS

'

18

REFERENCES 20

' FIGURES 23
ACKNOWLEDGMENTS

The support of the Center for Building Technology, Institute of

Applied Technology of the National Bureau of Standards is gratefully

acknowledged. Data acquisition was performed by Dr. S. K. Nayak and

Mr. G. L. Marsh with support by Mr. A. C. Hansen.
LIST OF FIGURES

Figure Page

1 Industrial Aerodynamics Wind Tunnel 23

2 Spire and Roughness Arrays 24

3 Photographs of Spire and Roughness Arrays 28

4 Mean Velocity Profiles--Flectilinear Form 29

i . 5 Mean Velocity Profiles--Logarithmic Form 30

6 Mean Velocity Profiles--Power Law Form- -Variation

with Longitudinal Position 31

7 Mean Velocity Profiles--Variation with Roughness

Height 33

8 Mean Velocity Profiles--Variation with Lateral

Position 34

9 . . Turbulence Intensity--Variation with Longitudinal

Position--Configuration 1 37

10 Turbulence Intensity--Variation with Lateral

Position--Configuration 1 38

. 11 Turbulence Intensity--Variation with Longitudinal

Position--Configuration 2 40

12 Turbulence Intensity- -Variation with Lateral

Position--Configuration 2 41

13 Turbulence Intensity--Referenced to U - 43 ref

14 Shear Stress- -Configuration 1 44

15 Shear Stress--Configuration 2 46

16 Longitudinal Space Correlation 48

17 Integral Scales 49

IS Velocity Spectra 50

19 Normalized Velocity Spectrum 52

iv

I
LIST OF SYMBOLS

Wind Tunnel Coordinate System

Reference Height for Profile Nondimensionalization

Effective Roughness Length

Local Mean Velocity

Mean Velocity^ at Height ^ Y ^ ret

Root-Mean-Square Velocity

Second Order Velocity Correlation

Separation Distance for Velocity Correlations

Zero-Crossing for Autocorrelation Functions

Normalized Longitudinal Velocity Space Correlation

Eulerian Integral Scale

Frequency in Hz

Velocity Spectral Function

Boundary Layer Thickness

V

I . INTRODUCTION

1 . 1 Scope of the Study

The design for wind effects on buildings has traditionally been

performed in a highly empirical manner. However, within the last decade

modeling techniques have been developed which permit the rational design

of structures for wind resistance--Cermak (3,4) and Davenport et al

.

Recent design approaches rely on the availability of wind pressure

information derived from measurements on small-scale models placed in

an "appropriate" wind tunnel.

The realization that wind tunnels can be used as an effective tool

in designing buildings against wind damage has caused considerable

thought and effort to be directed toward determination of what constitutes

an "appropriate" wind tunnel. A decade of research on turbulent boundary

layers formed over rough surfaces in a long (30-40 m) test-section wind

tunnel has demonstrated that a wind tunnel of this type is indeed

satisfactory and "appropriate"--Cermak (4). Unfortunately, long testsection wind tunnels are costly to build and require large buildings

for housing with the result that very few are now in existence--the

major facilities are located at Colorado State University and the

University of Western Ontario. On the other hand, many aeronautical

wind tunnels (short test-section type) exist throughout the world at

universities, government operated laboratories and industrial

laboratories. Although considerable effort has been expended in adapting

these short test -section wind tunnels to the modeling of atmospheric

flows (Section 1.2) , there is not a clear indication at this time that

satisfactory simulation can be achieved. Jensen (15) has demonstrated

that uniform flow or boundary- layer flows with the wrong turbulence
2

scale can lead to incorrect pressure distributions; therefore, the

pressure data from short test-section wind tunnels must be viewed with

caution. Development of a thick turbulent boundary layer in a short

test-section wind tunnel requires initial stimulation of the boundary

layer by some system of momentum sinks. Although devices such as

graded screens, grids, vortex generators, spires, roughness plates, etc.

have yielded reasonable vertical gradients of mean velocity, no

definitive study has been made to determine how realistic are the

resulting turbulence structures. ,

The purpose of this study was to develop an optimum system for

generating thick turbulent boundary layers with a proper integral scale

to simulate the atmospheric boundary layer in a short test-section wind

tunnel. In particular, a system was to be developed which could be

adapted to the 4 x 4 ft by 12 ft long test section of the University of

the Philippines wind tunnel to study wind pressures on buildings

resulting from typhoons.

1 . 2 Reyiew of Previous Modeling Techniques

The need for wind tunnels to study atmospheric flow phenomena has

prompted a number of investigators to convert existing short test-section

wind tunnels or to build wind tunnels with test sections significantly

shorter than required by a natural boundary layer development. Most of

these have been reported rather recently, since 1968.

Methods of generating turbulent shear flow have been known for many

years. Lawson (16) provided a review of those techniques and their

possible use for atmospheric flow simulation. Cowdrey (12) showed a

technique for designing horizontal rods to provide desired mean velocity

profiles. Cockrell and Lee (5) used horizontal rods designed with
3

Cowdrey's technique and also used solid "mixing wedges" on the tunnel

floor to simulate a neutrally stable atmospheric flow. Their technique

required a fairly long test section (approximately 40 duct heights)

before the boundary -layer settled down to an equilibrium condition.

An early use of vortex generators at the test section entrance to

simulate atmospheric flows was reported by Armitt and Counihan (1).

Their triangular wedge shape resulted in excessive organized longitudinal

vorticity at their test station. Further development of the vortex

generators with appropriate roughnesses has been performed by Counihan

(7-11) . His development has resulted in what he claims to be an

acceptable simulation of a neutrally stable boundary- layer flow four

and one-half boundary- layer heights downstream of the generators.

Because he presented no data upstream or downstream from his measurement station, it is not possible to determine whether or not the

boundary- layer was in a reasonable state of equilibrium. Triangular

vortex generators were used by Sundaram et al . (22) in combination with

a trip fence to demonstrate the technique of shortening the development

length. Their limited data showed some promise of successful simulation.

The Canadian National Research Council has had a program to develop

flow modeling in a short test section for several years. An early

attempt, Templin (23), used a grid of horizontal bars with little

success. Later attempts have used spires at the test section entrance.

Standen et al. (20), Standen (21), and Wardlaw (26) described the

technique and compared pressures measured on a structure with measurements in a conventional naturally developed boundary- layer and with

field measurements. While the extent of comparison was not sufficiently extensive to demonstrate complete acceptability, the
4

technique did show promise. Approximately six boundary -layer heights

were required to establish equilibrium. Some of their data indicated a

possibility of undesirable organized vorticity in the outer portions of

the boundary -layer. A spire -generated boundary -layer was also used by

Dreher and Cermak (14) at Colorado State University. However, the

mean velocity profile showed distortions characteristic of too small a

surface-roughness height.

Two investigators have used a coarse grid covering the entire

cross section combined with a two-dimensional barrier fence acroSiS the

floor either upstream or downstreani of the grid. Barrett (2) used an

upstream barrier with grid to develop the boundary layer and to even out

nonuniformities from a high-angle diffuser a short distance upstream.

Significant nonuniformities in the approach flow did not permit a good

evaluation of the boundary -layer -generation technique. Cook (6), using

a barrier downstream of his grid developed a boundary layer simulating

the lower one-third of the atmospheric boundary layer with a realistic

integral scale. However, his roughness elements were spaced sufficiently

closely that a large effective wall displacement occurred.

Fluid barriers or trips have been used by several investigators.

Teunissen (24,25) used an array of jets pointing in the direction of the

main flow to provide turbulence structure and mean velocity defect to

simulate atmospheric flow in an 8 x 8 inch duct. He found it necessary to

includp a two-dimensional solid fence to trip the flow and carefully

selected floor roughness to properly simulate an atmospheric flow. The

simulation was very encouraging; however, scale-up to a facility large

enough to accomodate a model at 1:200 to 1:400 has not yet been

demonstrated. Schon and Mery (19) used a jet blowing perpendicular to
5

the main flow at the leading edge to thicken their boundary layer. They

were limited in the thickness of the boundary layer they could develop

by this technique. Morkovin et al. (17) used a row of counter-jets at

floor level directed upstream at various angles to the flow. They did

not measure sufficient turbulence properties to indicate acceptability

of their simulation. Nee (18) has recently completed a wind tunnel

which will use lateral jets to control the flow properties.
6

II. WIND SIMULATION FACILITIES

2.1 Wind Tunnel

The study was performed in the Industrial Aerodynamics Wind Tunnel

at Colorado State University (Fig. 1). The test section is 6 x 6 ft

in cross section with a length of 36.5 ft and contraction ratio of 4:1.

An axial-flow blower driven by a 75 hp constant speed motor provides

wind velocities up to 65 ft/sec. Continuous variation of wind speed is

accomplished by varying the fan blade pitch.

2 . 2 Spire and Roughness Arrays

The intent of the study was to determine a combination of

disturbance devices and roughnesses to simulate a neutral atmospheric

flow for two classes of roughness defined by mean velocity power-law

exponents in the ranges 0.14-0.20 and 0.28-0.35. A location 18 ft

downstream in the test section was selected as the cross section at which

the boundary -layer simulation would be targeted. This location was

scaled to the end of the 12 ft test section of the University of the

Philippines wind tunnel. In order to provide a flow in which models

as large as 1:50 could be used, as deep a boundary layer as possible

was desired, even to the point of modeling only the lower portion of the

atmospheric boundary layer.

With the present status of expertise in generating artificially

stimulated boundary layers outlined in Section 1.2, spires with a

roughened floor were selected as the most likely means of obtaining an

acceptable simulation. Spires used in a previous study (14) provided a

starting point for spire geometry. A number of spire geometries and

roughness heights were tried. Two combinations of spires and roughness
7

were found which met the power law velocity-exponent criteria. The

spire and roughness array geometries are shown in Fig. 2. Configuration 1

yielded a profile in the 0.28-0.35 range while Configuration 2 provided

a profile close to the 0.14-0.20 range. Photographs of Configurations 1.

and 2 are shown in Fig. 3.

2 . 3 Instrumentation and Data Acquisition

During the initial stages where spire and roughnesses were selected,

most mean velocity profiles were obtained with a pitot tube with

pressure differences measured with an MKS Baratron pressure transducer.

For final data (including all data presented in this report), velocity

data was taken by hot-wire anemometer. Data associated with Configuration

1 was taken with a Thermosystems Model 1054B constant temperature

anemometer on loan from National Bureau of Standards for checkout

purposes. The remainder of the data was taken with a DISA model 55D01

constant temperature anemometer.

Autocorrelations, space correlations and spectra were obtained for

selected locations. Autocorrelations for Configuration 1 were obtained

using a Saicor Model SAI-43A Correlation and Probability Analyzer which

was on loan from National Bureau of Standards for checkout. The

remaining correlations were obtained on a Princeton Correlator. Spectra

were obtained by Fourier transform of the correlations. Each correlation

was digitized at two millisecond intervals (300-350 points per correlation) and transformed by a Fast -Fourier -Transform algorithm on the CSU

CDC 6400 computer.

Six measurement stations were defined in the wind tunnel, two

each at three downstream positions. The three longitudinal positions

were at X=14, 18 and 28 ft from the spires at the test -section entrance
8

(see Fig. 2 for coordinate system). At each of these distances,

measurement stations were located on the centerline of the wind tunnel

and 1/2 spire spacing off the centerline. At each of these six stations,

data was taken along a vertical line. Mean velocity and turbulence

data were taken at all stations on a vertical traverse spanning the

entire boundary-layer thickness. Correlations and spectra were taken

at selected locations chosen to show certain features of the turbulent

structure.

K. i

!
9

III. RESULTS

3. 1 Mean Velocity

The mean velocity profiles for the two desired power law exponent

flows are shown in Fig. 4. The data is nondimensionalized with respect

to the velocity U _ measured at a height Y ». These reference ^ ref ^ ref

values are not intended to represent the edge of the simulated boundary

layer flow but a convenient position for nondimensionalization. The

best value to use for the simulated boundary- layer thickness will

depend on the scale of models to be placed in the flow. This scale

should not be selected until the turbulent properties of the flow have

been examined. A value of Y of 52 inches was selected to nonre f

dimensionalize all data since all mean velocity profiles measured

obeyed a power law to that height. Some profiles had a power law profile to a height of as much as 58 inches before effects of the ceiling

boundary layer were felt. The solid lines in Fig. 4 represent a least

squares fit of the data to a power-law velocity profile. The exponents

were found to be 0.312 and 0.138.

An important criterion in the simulation of atmospheric flows is

the effective roughness length. Significant difficulties were

encountered in this study in that excessively large values tended to

occur. This difficulty was also evident in several of the reviewed

publications. The final solutions for the present simulation represent

reasonably acceptable values. Logarithmic plots of the data from

Fig. 4 are shown in Fig. 5. As expected, a large portion of the boundary

layer followed a logarithmic relationship. Roughness lengths Y^

determined from the graph are 0.884 inches for Configuration 1 (n=0.312)

and Y =0.01 inches for Configuration 2 (n=0.138). The corresponding
10

prototype roughness lengths range from 22 to 88 inches for model scales

of 1:25 to 1:100 for Configuration 1 and from 0.25 to 1.0 inches for

Configuration 2. These values fall within the range of field values

expected for the power law profiles given.

One of the greatest difficulties in developing a boundary layer

with artificial stimulation has been that of generating a flow which

is in equilibrium. Only the spire configuration used by the National

Research Council (20, 21) and the multiple jet "racility reported by

Teunissen (25) have demonstrated some measure of equilibrium. The

Canadian study required six spire heights to establish equilibrium--a

condition which, for this study with a short test-section length

available, would limit spires (and consequently boundary layer height)

to less than half the wind tunnel height. Teunissen had such a small

range of frequencies between the peak of his spectrum and viscous

dissipation that his boundary layer reached equilibrium more quickly--

about Ah tunnel heights downstream. The desire for equilibrium in

three tunnel heights (4.1 Y^^^) in the present study represents a severe

requirement. A necessary (but not sufficient) condition for equilibrium

is a mean velocity profile invarient with longitudinal position. Figure

6 shows the mean velocity profiles for the three longitudinal measurement

positions for both Configurations 1 and 2, plotted on log-log scales to

show the power law relationship of the profiles. The solid lines are

least square fits for the exponent n. The variation in exponent for

Configuration 1 was from 0.336 to 0.245 from X=14 ft to X=28 ft. While

the variation was not exceedingly large, equilibrium has certainly not

been indicated in the strictest sense. The profiles for Configuration 2

show a variation with downstream extent sufficiently small to indicate

the possibility of a fully developed flow.
11

An equilibrium boundary layer maintains itself by balancing the

production of turbulence which is influenced by the roughness with the

dissipation of that turbulent energy in viscous effects. The decay in

exponent for Configuration 1 indicates that, for the given roughness, the

boundary layer was seeking an exponent lower than those shown in Fig. 5

as it approached closer-to equilibrium. It also indicates that larger

roughness elements would be required in the region from X=14 to 28 ft to

maintain an exponent in the range of 0.28-0.35 desired for a solution

in Configuration 1. However, it was found that, for a particular spire,

the roughness required to force a power- law variation in mean velocity

was fixed--that is, one is not free to arbitrarily select a roughness to

vary the exponent. A particular spire demands a particular roughness to

obtain a power- law variation in mean velocity and together they define an

exponent which may vary with downwind position. This need for a particular roughness has been noted before and was most clearly shown by Standen

(21). His profiles showed two distinct power-law regions with incorrect

roughness leading to the concept that the spires controlled the profile

shape in the outer region of the boundary layer and the roughness controlled the profile shape in the inner portions. This concept, however,

oversimplifies the mechanism. The roughness actually affects the profile

over the entire height as is demonstrated in Fig. 7. Four mean velocity

profiles are shown representing the solution profile for Configuration

1 and three alternate roughness heights. The data shows that the

effects of spires and roughness interact so strongly that they must

be considered together in their effect on the flow. This makes the

design of a spire and roughness array to obtain a particular result

(say a desired power-law exponent) a difficult task since one cannot, for
12

example, determine the effect of varying spire width without also

trying a series of roughnesses with each spire width. It is thus not

evident from the data shown in Figs. 4 and 5 what variations in spires

and roughness would result in a mean velocity profile more stable in

longitudinal variation than the data for Configuration 1.

It was found during the early testing that the spires followed by

a roughness of uniform height did not produce a power law profile at the

X=18 ft measurement station as readily as a roughness which was higher

near- the spires than farther down the test section. The effect of the

roughness height gradation used for Configuration 1 appears to have the

same effects as the barriers used previously by a number of investigators

(2, 6, 7-11, 22, 25)

.

One concern resulting from the use of spires was the spanwise

variation of flow properties. Figure 8 shows the comparison of the

centerline mean velocity profile with the profile located 1/2 the spire

span laterally from the centerline. Data is shown for Configurations 1

and 2 for all three longitudinal measuring stations. The agreement is

generally within the measurement tolerance and no indication of a wake

effect is evident in the mean velocity profiles. A more stringent test

of lateral uniformity is the comparison of turbulence intensity profiles

discussed in the next section.

3 . 2 Turbulence Intensity and Shear Stress

- Turbulence intensity profiles showing longitudinal variation on

the tunnel centerline for Configuration 1 are shown in Fig. 9. The

vertical distance has been scaled by the distance Y as was done for ret

the mean velocity profiles. The magnitude of turbulence intensity is

realistic for simulation of an atmospheric boundary layer. The decay
13

of intensity with longitudinal position is consistent with the decay of

exponent noted above and provides further evidence that the flow was not

in equilibrium but was seeking a profile of lower power- law exponent and

lower turbulence intensity than was reached by 28 ft downstream. Figure 10

shows the lateral variation at the three measurement stations. Since

turbulence decays at a slower rate than velocity defect in a wake flow,

these profiles should be more sensitive to any remaining wake effects of

the individual spires than the mean velocity profiles. An acceptable

lateral uniformity is thus indicated for all three stations.

Longitudinal variation of turbulence intensity for Configuration 2

is shown in Fig. 11. The indication from the mean velocity profiles

(Fig. 6) was that little or no change in profile shape was occurring

with downstream position. The turbulence profiles, however, show a

steady decay of turbulence intensity indicating that the boundary layer

was not in equilibrium. Within therange of X=14 to 18 ft, the turbulence

variation was small and could represent a flow sufficiently close to

equilibrium for many measurement purposes. The overall level of

turbulence intensity was somewhat below that expected for an atmospheric

flow with the same power -law exponent. Figure 12 shows the lateral

variation at all three measurement stations. The uniformity is

acceptable.

Figure 13 demonstrates the absolute magnitude of the turbulence by

referencing the rms velocity to the constant velocity U^g£ at height

^j.Qf Configuration 1 has a turbulent intensity approximately constant

up to about 1/3 of the Y^^^ height. Configuration 2 shows a roughly

constant, but smaller, value to approximately 1/4 Y ^.
14

Shear stress profiles for Configuration 1 are shown in Fig. 14,

Both variation with longitudinal position and lateral displacement are

shown. Good lateral uniformity is demonstrated but is to be expected

from the turbulent intensity results. The lateral uniformity results

are a good measure of the precision of the measurements. A steady decay

of shear stress magnitude is shown with increasing longitudinal distance.

This variation reflects the decay shown in power law exponent and

turbulent intensity discussed above. It is difficult to define a region

of solidly constant shear stress, but the region from the top of the

roughness elements to about 1/3 of the Y^^^ height could be considered

to be a region of reasonably constant stress.

Shear stress results for Configuration 2 are shown in Fig. 15.

The lateral uniformity again is good. Decay of shear stress with

longitudinal position is consistent with the turbulent intensity

results and confirms that the boundary layer was not in equilibrium in

the longitudinal range considered.

3.3 Correlations, Integral Scales and Spectra

Longitudinal velocity correlations were taken at several heights

above the wind-tunnel floor at all three measurement stations for both

spire and roughness configurations. In addition, several correlations

were taken at locations laterally spaced from the centerline to check

for possible nonuniformities . Two correlations obtained at X=18',

Y=13" on the centerline for Configuration 1 are shown in Fig. 16. The

curves are in the form of a normalized longitudinal space correlation

and are typical of all correlations measured. The solid line was

obtained by an autocorrelation of a single hot wire and using Taylor's

9 9 hypothesis = V —) to convert to a space frame. The correlation
15

has an unusual feature: a long negative tail extending past 100 inches

(or about 1/2 second in time). When integral scales were computed from

this and other correlation curves by the formula

it was found that the positive area was nearly balanced by the negative

area causing the calculated integral scale to be unrealistically small,

and in some cases negative. Since the use of formula 1 to obtain

integral scales from an autocorrelation requires that Taylor's hypothesis

is valid, a check of the validity of that hypothesis was made by

obtaining the correlation of physically spaced hot wires. The results

of that investigation are shown in Fig. 16 as circles. The larger the

distance that the circles fall below the solid curve, the less is the

accuracy of the hypothesis. The reasonable agreement shown is an

indication that, while not precisely correct for this flow, the

hypothesis is acceptable for the computation of integral scales. It is

possible that the long negative tail of the correlation is, in fact,

dye to the already demonstrated lack of equilibrium in the flow. All

correlations measured showed this same characteristic tail although

those from Configuration 2 were not as long.

Integral scales were finally obtained by use of the formula

where is the first zero crossing of the correlation function. This

provides an estimate of the integral scale which should be fairly close

to the correct value. The error in an estimate of this type should be

such that the scale is slightly overestimated. This calculation

00 (1)

X

(2)
16

procedure is rather conunon, especially for atmospheric measurements, so

that the values obtained should be useful for comparison of the boundary

layer with atmospheric flow. The variation of integral scale with

height and longitudinal position in the boundary layer for both

configurations is shown in Fig. 17. The scale increases with height--

as in the atmosphere- -over the lower portion of the boundary layer but

decreases again at larger heights. This decrease with height above the

lower levels is a characteristic of most wind-tunnel simulations with

a shoi|t test- section. The absolute magnitude of the integral scale

compared to the atmosphere must be considered with the scale of the

model to be employed. This will be discussed in Chapter IV.

The variation of integral scale with longitudinal position is shown

in Fig. 17 at a constant elevation. Since the height chosen was near

the peak scale for both configurations and because the tunnel boundarylayer thickness varied little with downstream distance, the trend of

the integral scale is an indication of real development within the

boundary layer. Again the indication is that, within the test region

investigated, the boundary layer was seeking but had not quite attained,

an equilibrium condition.

A longitudinal velocity spectrum is shown in dimensional form in

Fig. 18a. The location is at 18 ft downstream and at 25 percent of

the reference height for Configuration 1 at a point where the integral

scale is still increasing with height. The important feature is the

slope of the curve in the inertial subrange. A slope of -1.46 was

obtained which is significantly different from -1.67 slope expected from

a turbulence in equilibrium. A comparison of the spectra for several

locations in the flow for both configurations is shown in Fig. 18b to
17

illustrate the vertical and longitudinal variations. It can be observed

that the slopes, in general, tend to approach closer to the -1.67 value

with increased longitudinal position and decreased turbulence intensity.

This data further confirms statements made above relative to the

equilibrium of the flow.

Figure 19 shows the velocity spectrum of Fig. 18a in

nondimensionalized form. The location of the peak in amplitude and

position in the frequencly domain was similar for the other spectra.

The slope in the decay region was also similar although, as noted

above, the slopes tended to be steeper for some situations. The

frequency scale is commonly nondimensionalized in the form nL/U

where L is some characteristic length such as the integral scale

and U is the velocity at the elevation of interest. Since these

values are related to the scale of the model involved, a discussion of

the location of the peak referenced to these variables will be delayed

until Chapter IV.
18

IV. CONCLUSIONS

, IWind-tunnel simulations of atmospheric boundary -layer flow were

obtained for two power law exponents at a station located three tunnel

heights downstream of the test- section entrance with a 6 x 6 ft cross

section wind tunnel. Spires extending the full height of the test

section and appropriate roughness were used t~ generate a 52 inch deep

boundary layer. Mean velocity profiles followed power- law relationships

over virtually the entire height. Turbulence intensities were reasonable

for the case with a=0.3 but slightly low for the case with a=0.14.

Shear stress profiles were within an acceptable range although the

depth of the roughly constant stress layer was not as large as might

be desired.

The equilibrium of the boundary layers was examined using mean

velocity, turbulence and shear stress profiles, integral scales and

velocity spectra. The indications were that the boundary layers were

not in equilibrium as far downstream as 4.7 wind-tunnel heights.

Sufficient evidence is not presently available to demonstrate whether

or not the flows were sufficiently close to equilibrium that errors in

measurements on or about a model placed in the flows would be

acceptably small. It is likely that such errors would be reasonably

small.

The size of model which could be tested in the boundary layers

generated in this study can be determined by examining the integral

scales, the peak of the nondimensional spectra and the effective

roughness length. Integral scales in the atmosphere generally run from

about 400 to 700 ft. However, in typhoons the scales can be in the

neighborhood of 200 ft. Using 200 ft as a reasonable target for wind
19

simulation tests which would be of interest for the Philippines area,

the 0.4 and 0.6 ft scales measured in the two boundary layers give

model scales of 1:300 to 1:500, say 1:400 as an average. Using an

atmospheric boundary- layer thickness of 1000 and 1600 ft for the cases

6 = 0.14 and 0.30. The wind tunnel boundary- layer thickness for this

scale would be Y^^ = 2.5 ft and 4.0 ft- -within the depth established for

the two boundary layers.

Nondimensionalization of the velocity spectrum frequency scale

by the term n6/U tends to collapse atmospheric data to a single

curve (23). The factor 5 represents the atmospheric boundary- layer

thickness. The peak of the spectra occur at n6/U = 0.35 with the

2 ordinate in the form nF(n)/U . Applying this criteria to the wind

rms ff J b

tunnel flows where the peak in the spectrum occurred at n = 2 (Fig. 19),

values of 6 were calculated to be 3.8 ft and 5.0 ft for Configuration

1 and 2 respectively. Assuming full scale values of 6 of 1200 ft

and 900 ft for the two power law profiles leads to wind tunnel scales

of 1:300 for Configuration 1 and 1:180 for Configuration 2.

At scales of 1:300 and 1:180, the effective roughness lengths of

.884 inches and 0.01 inches for a = 0.3 and 0.14 respectively are 22 ft

and .15 ft in the prototype. The value for Configuration 1 is large by

a factor of three or more. While a zero-plane displacement could be

used to reduce the roughness length, it involves a rather arbitrary

assignment of a displacement which would not improve either the

logarithmic or power- law description of the mean velocity profile. At

scales of 1:300 and 1:180 the integral scales for the prototype become

180 ft and 72 ft for Configurations 1 and 2. These are somewhat small.
20

REFERENCES

a.. Armitt, J. and J. Counihan, THE SIMULATION OF THE ATMOSPHERIC

BOUNDARY LAYER IN A WIND TUNNEL, Atmospheric Environment, Vol. 2,

pp. 49-71, 1968.

2. Barrett, R. V., A VERSATILE COMPACT WIND TUNNEL FOR INDUSTRIAL

AERODYNAMICS, Technical Note, Atmospheric Environment, Vol. 6,

pp. 491-498, 1972.

3. Cermak, J. E., V. A. Sandborn, E. J. Plate, G. H. Binder, H. Chuang,

R. N. Meroney and S. Ito, SIMULATION OF ATMOSPHERIC MOTION BY WIND

TUNNEL FLOWS, Report CER66JEC-VAS-EJP-GJB-HC-RNM-SI 17 , Fluid

Mechanics Program, Colorado State Univ., 1966.

t 4. Cermak, J. E., LABORATORY SIMULATION OF THE ATMOSPHERIC BOUNDARY

LAYER, AIAA Jl, Vol. 9, pP- 1746-1754, 1971.

5. Cockrell, D. J. and B. E. Lee, METHODS AND CONSEQUENCES OF

ATMOSPHERIC BOUNDARY LAYER SIMULATION, Paper 13-AGARD Conference

. Proc. No. 48 on Aerodynamics of Atmospheric Shear Flows, Munich,

1969.

6. Cook, N. J., ON SIMULATING THE LOWER THIRD OF THE URBAN ADIABATIC

BOUNDARY LAYER IN A WIND TUNNEL, Atmospheric Environment, Vol. 7,

pp. 691-705, 1973.

7. Counihan, J., AN IMPROVED METHOD OF SIMULATING AN ATMOSPHERIC

BOUNDARY LAYER IN A WIND TUNNEL, Atmospheric Environment, Vol. 3,

pp. 197-214, 1969.

8. Counihan, J., A METHOD OF SIMULATING A NEUTRAL ATMOSPHERIC BOUNDARY

LAYER IN A WIND TUNNEL, Paper 14-AGARD Conference Proc. No. 48 on Aerodynamics of Atmospheric Shear Flows, Munich, 1969.

9. Counihan, J., FURTHER MEASUREMENTS IN A SIMULATED ATMOSPHERIC

BOUNDARY LAYER, Atmospheric Environment, Vol. 4, pp. 259-275, 1970.

10. Counihan, J., WIND TUNNEL DETERMINATION OF THE ROUGHNESS LENGTH AS

A FUNCTION OF THE FETCH AND THE ROUGHNESS DENSITY OF THREEDIMENSIONAL ROUGHNESS ELEMENTS, Atmospheric Environment, Vol. 5,

pp. 637-642, 1971.

11. Jounihan, J., SIMULATION OF AN ADIABATIC URBAN BOUNDARY LAYER IN A

WIND TUNNEL, Atmospheric Environment, Vol. 7, pp. 673-689, 1973.

12. Cowdrey, C. F., TWO TOPICS OF INTEREST IN EXPERIMENTAL INDUSTRIAL

AERODYNAMICS, Symposium on Wind Effects on Buildings and Structures,

National Physical Laboratory, Teddington, 1968.
21

13. Davenport, A. G. and N. Isyumov, THE APPLICATION OF THE BOUNDARY

LAYER WIND TUNNEL TO THE PREDICTION OF WIND LOADING, Proc.

International Research Seminar on Wind Effects on Buildings and

Structures, Vol. 1, National Research Council, Canada, 1967.

14. Dreher, K. J. and J. E. Cermak, WIND LOADS ON A HOUSE ROOF, Report

CER72-73KJD-JEC22, Fluid Mechanics Program, 1973.

15. Jensen, M. , THE MODEL-LAW FOR PHENOMENA IN A NATURAL WIND,

Ingenioren (International Edition), Vol. 2, pp. 121-128, 1958.

16. Lawson, T. V., METHODS OF PRODUCING VELOCITY PROFILES IN WIND

TUNNELS, Research Note, Atmospheric Environment, Vol. 2, pp. 73-76,

1968.

17. Morkovin, M. V., H. M. Nagib and J. T. Yung, ON MODELING OF

ATMOSPHERIC SURFACE LAYERS BY THE COUNTER-JET TECHNIQUE--PRELIMINARY

RESULTS, Report AFOSR-TR-73-0592, Illinois Institute of Technology,

1972.

18. Nee, V. W. , C. Dietrick, R. Betchov and A. A. Szewczyk, THE

SIMULATION OF THE ATMOSPHERIC SURFACE LAYER WITH VOLUMETRIC FLOW

CONTROL, Realism in Environmental Protection and Control, Proc. 19th

Annual Tech. Meeting, Institute of Environmental Science, Anaheim,

Calif. , pp. 483-487, 1973.

19. Schon, J. P. and P. Mery, A PRELIMINARY STUDY OF THE SIMULATION OF

NEUTRAL ATMOSPHERIC BOUNDARY LAYER USING AIR INJECTION IN A WIND

TUNNEL, Atmospheric Environment, Vol. 5, pp. 299-311, 1971.

20. Standen, N. M. , W. A. Dalgliesh and R. J. Templin, A WIND TUNNEL AND

- FULL-SCALE STUDY OF TURBULENT WIND PRESSURES ON A TALL BUILDING,

Proc. Third International Conference on Wind Effects on Buildings

and Structures, Tokyo, Japan, 1971.

21. Standen, N. M., A SPIRE ARRAY FOR GENERATING THICK TURBULENT SHEAR

LAYERS FOR NATURAL WIND SIMULATION IN WIND TUNNELS, Report LTR-LA94, National Aeronautical Establishment, Ottawa, Canada, 1972.

22. Sundaram, T. R., G. R. Ludwig and G. T. Skinner, MODELING OF THE

TURBULENCE STRUCTURE OF THE ATMOSPHERIC SURFACE LAYER, AIAA Jl,

Vol. 10, pp. 743-750, 1972.

23. Templin, R. J., INTERIM PROGRESS NOTE ON SIMULATION OF EARTH'S

SURFACE WINDS BY ARTIFICIALLY THICKENED WIND TUNNEL BOUNDARY LAYERS,

Report LTR-LA-22, National Aeronautical Establishment, Ottawa,

Canada, 1969.

24. Teunissen, H. W., AN INJECTOR-DRIVEN WIND TUNNEL FOR THE GENERATION

OF TURBULENT FLOWS WITH ARBITRARY MEAN VELOCITY PROFILE, Tech. Note

133, University of Toronto Institute for Aerospace Studies, Toronto,

1969.
22

25. Teunissen, H. W. , SIMULATION OF THE PLANETARY BOUNDARY LAYER IN

A MULTIPLE-JET WIND TUNNEL, Report 182, University of Toronto

Institute for Aerospace Studies, Toronto, 1972.

26. Wardlaw, R. L., WIND TUNNEL INVESTIGATIONS IN INDUSTRIAL

AERODYNAMICS, Canadian Aeronautics and Space Journal, Vol. 18,

pp. 53-59, 1972.
23 /

1^ 1 <

_l

Q.

.9"o o o o o o o o o o o o o o o o o o O O O G O O

I-<>

UJ

_l

Ld o

+-> uo H ^03 C

•H

C

3: o

•H

t/5 (/) O 3

•H <4-l

H S U-l (U 3 -H >

uff 3 O

f-i to <U

<D

O (-> < -H OS

c3 CO

+J 03

t/1 73 f-i 13 -H O 3 —I C --H O

tU

U

•H

03
24

Origin of

Coordinate

System

Continue Roughness Rows

at 12" Spacing

y Coordinate- Dist. Above

Wind Tunnel Floor

Rows Height, in 1,2 6-3/4

3-10 4-1/2

ll-On 2-1/4

Each Roughness Dimension!

8-5/8" X 3-5/8"

Wind Tunnel Configuration

Fig. 2. Spire and Roughness Arrays
Spire for Configuration I

Fig. 2. Spire and Roughness Arrays (continued)
26

Origin of

Coordinate System

No Roughness

Spire

y Coordinate -Dist. Above Wind Tunnel Floor

Wind Tunnel Configuration 2

Fig. 2. Spire and Roughness Arrays (continued)
Fig. 2. Spire and Roughness Arrays (continued)
28

Configuration 2

Fig. 3. Spire and Roughness Arrays
29

U/Uref

Fig. 4. Mean Velocity Profiles--Recti linear Form
U/Uref

Fig, 5. Mean Velocity Profiles--Logarithmic Form
Fig. 6. Mean Velocity Profiles--Power Law Form--Variation

with Longitudinal Position
1.00 32

1—-i

\

1 I O

Spire and Roughness Configuration 2

^ x= 14' , z =0'

o x= 18' , z =0'

x = 28' , z=0'

Yref =52"

0)

>- 0. 10

n = O.I38

0.01 I I L U/Uref

10

Fig, 6. Mean Velocity Profiles--Power Law Form--Variation

with Longitudinal Position (continued)
I ' I—I

r

00- OJ — Otn

c

o

3

C

o

o

l_l l_l 1 J . L

<Uc

o o =

cr 5cvj_o

O , I I 0- — ro —

CD6

d

c

q: 5rooo— o o I I I I

CDd

d

J L—J-

.2 ^x-(D^c^-

o

or ^1 c o rv ' ' ' '

CDd

6

o

q

o

00

o

CD o o o CDo

CDo o o o

6 6 d d d d d d d d
34

00

>-"0. I 0

0.0

Symbol

o

€^ O

Lateral

Location

1——r-—r—i—

Spire - Roughness

Configuration

0.

z =0 (Centerline)

z =0 " 2

z =0.958'(l/2 Spire Spacing)

z =0.740' 2

Yref =52"

X =14' All Data

U

Uref \Yref

Y

n = 0.336 n = O.I38

.0

U/Uref

Fig. 8. Mean Velocity Profiles--Variation with Lateral Position
0.01 J- -J I I L—I L U/Uref

Fig. 8. Mean Velocity Profiles--Variation with Lateral Position (continued)
n = 0.245 n=O.I38

0.01

0.

U/Uref

.0

Fig. 8. Mean Velocity Profiles--Variation with Lateral Position (continued)
37

I .OrCXh^j r OA

O A

O A

O A

Spire and Roughness Configuration I A X = I 4' ,2 =0

O.sh °0 A O X = I 8' .z=0

O A

0.6 -

0.4

0.2.

n X =2 8' ,z =0

Yref =5 2"

OA

O A

O A

OA

OA

OA

OA

OA

OAOA

OAOAOAOAOA

O A

O A

O A OA I I in A

10 20 30 40

Urms -^U, percent

Fig. 9. Turbulence Intensity-- Variation with Longitudinal Position--

Configuration 1
.0

0.8

Q

Q

38

Spire and Roughness Configuration

O X = 18' ,z =0

A X = I 8' ,z =0.958'

^ref

52"

0.6

0.4 -

0.2

V

0

0

AO

A O

A O

AO

A O

A O

O

A O

A O

A O

A O

A O

4D

^RIVIS percent

40=

40

Fig. 10. Turbulence Intensity--Variation with Lateral PositionConfiguration 1
39

I .OrCW^^ -T <P c

<d O

en

^

on 0

.OD

^ ^ X = 14' ,z =0.958'

Spire and Roughness Configuration I A X = 14' ,z =0

<n

^

<P

^

Yref =52"

x=28' ,z =0

O x=28' , z =0

on C

OD

03 y A

On V ^ on V A

on ^ A

on y A

On ^

<p VA

on ^

Cn O

on V A

d ^ A

no y A

n o VA

J— o I ^ OL

0 10 20 30 40

Fig. 10. Turbulence Intensity--Variation with Lateral Position--

Configuration 1 (continued)
40

I .Or-O-Q

cn

L OA

OA

0.8

0.6

a>

0.4

0.2

0

O A

O A

O A

O A

O A

O A

O A

O A

O A

O A

O A

Spire and Roughness Configuration 2

A X = I 4' ,z = 0

O X = I 8

' ,z = 0

X =28' ,z = 0

Q

O ^

O A

O A

OA

O A

O A

O A

O

XI ClJL

0 10 15

^RMS ' P®''cent

20 25

Fig. 11. Turbulence Intensity--Variation with Longitudinal PositionConfiguration 2
41

A O

A O

AO

AO

Spire and Roughness Configuration 2

O X = I 8' ,z = 0

A X = I 8' ,z =0.740'

AO

AO

AO

Co

AO

CD

AO

CO

A O

A O

A O

A O

A O

A O

A O

A O

A O

CO

Yref =52"

J O-J A0 5 10 15 20 25

Up|^5/U, percent

Fig. 12. Turbulence Intensity--Variation with Lateral PositionConfiguration 2
42

o o

0.8

0.6

0.4

0.2

^ ^ Spire and Roughness Configuration 2

<3D

^ Ax =l4'.z = 0

<C: ^ V X = 14' ,z =0.740'

X =28' ,z = 0

<P

^ Ox =28' .z = 0.740'

Yref = 52"

<P

^

<p

^

- <P

^

<p

^

<tl ^

< ^

> ^

O ^

<P

^

t!> A^

<P A V

CD AV

q> A ^

a>

^

^

n JXZ

10 15 20

Urivis/U, percent

Fig. 12. Turbulence Intensity--Variation with Lateral

Configuration 2 (continued)
43

0.8

0.6

O-i^j

CD

AO

A

A

A

A

O Configuration I , x = 18' , z = 0 ^ Configuration 2 , x = I 8' , z = 0

Yref = 52'

0.4

0.2

A

A

A

C

A

A

A

A

O

O

o

o

o

o

o

o

.A.

0 5 10

^RMs/^ref percent

15

Fig. 13. Turbulence Intensity--Referenced to U
44

.0 T 1 1 T T r

0.9

0.8

AO

OA

Spire and Roughness Configuration 2

O X = I 8' , z = 0

A X =18' ,z =0.958'

0.7 AO

0.6

A o

0) >-"0.5

AO

A O

0.4

0.3

0.2

Roughness

Height

A O

A

AO

O

A O

A O

O

n n

0

A OJ L J 1 I I 0 0.002 0.004

u' v

Uref^

0.006

. Fig. 14. Shear Stress--Configuration 1
45

OrO0.9

0.8

0.7

0.6

>^ 0.5

0.4

0.3

0.2

A o

OA

OA

ADO

AD

An

Spire and Roughness Configuration

^ X = 14' ,z=0

O X = 18' ,z =0

X =28' ,z = 0

Roughness

Height

I r r > A O

Q

OA

OA

OA

O

o A

OA

o A

O DA

O

0.002 0.004 0.006

Uref

Fig. 14. Shear Stress--Configuration 1 (continued)
46

I .0

0.9

0.8

as

OA

AO

Spire and Roughness Configuration 2

O X =18' , z = 0

A X = 18' ,z = 0.740'

0.7 AO

0.6 - OA

>?0.5 - OA

OA

0.4 -

0.3 -

0.2

0^1

O A

OA

OA

OA

A O

AO

c3S

CD

O A

O A

J EJ. 0 0.002 0.004

U'V

Uref

0.006

Fig. 15. Shear Stress- -Configuration 2
47

1.0 I——Ot^

0 9- ^'^^ Spire and Roughness Configuration 2

A X = I 4' ,2 = 0

0.8 |- O X = 18' ,z = 0

X =23 ,z = 0

0.6

a; >0.5

6o

AO

0.4

O A

0.3 1- D OA

OA OAO A

OA

O A

OA

OA

oi_EA_j q

0 0.002 0.004 0.006

0.2

0

Uref^

Fig. 15. Shear Stress--Configuration 2 (continued)
48

Ooo ^6666 10 cvj o ojO c\i d d

I I
49

0.8

1 1 1 1 1 1

X = 1 8

'

z =0

Yref = 52"

0.6

X

-J 0.4

- X

"^^'^^onfiguration 1

0

<i-W ^

Configuration 2 \

0.2

n 1

1 1 1 1 1 0 0.2 0.4 0.6

0.8

1 1 1 1 1

. Y/Y,ef =0.25

1 1 1 1

0.6 —o

0.4

Configuration 2

0.2

n 1 1 1 1 1 1 1 1 1 12 14 16 18 20 22 24 26 28 30

X, ft

Fig, 17. Integral Scales
50

1 1 1 1 I I I

1 1 1 1 1

1 I I

0 01 I ' ' ' "—J 1

I I I 1 L- 1 '

' 1.0 10.0 100.0

n, cps

Fig. 18. Velocity Spectra
51

10.0 r—I—!—I I I I I n

-—I 1—I

I I I I I

1 1 1—I

I I I I

n, cps

Fig. 18. Velocity Spectra (continued)
52

q

I I — I 1 I t I I

•!—' I' I I —1 5

( u)d u
APPENDIX C

BIBLIOGRAPHY OF WIND RELATED DOCUMENTS

C-1

1. NBS Technical Note 558, "Lubbock Tornado: A Survey of Building

Damage in an Urban Area;" Somes, Dikkers , & Boone

2. NBS Technical Note 563, "Surface Pressure Fluctuations Near an Axisymmetric

Stagnation Point;" Marshall.

3. NBS Technical Note 569, "Hurricane Camille - August 1969,"

Dikkers, Marshall & Thom.

4. NBS Technical Note 706, "Structural Performance Evaluation of

Innovative Building Systems," Yokel & Somes

5. BSS 1, "Performance of Buildings - Concept and Measurement," Walton

and Cadoff

6. BSS 8, "Interrelations Between Cement & Concrete Properties, Part 3,"

Blaine , Ami , and DeFore

7. BSS 13, "shrinkage and Creep in Prestressed Concrete," Petersen and Watstein.

8. BSS 14, "Experimental Determination of Eccentricity of Floor Loads

Applied to a Bearing Wall," Watstein and Johnson.

9. BSS 15, "Interrelations Between Cement & Concrete Properties, Part 4,"

Blaine, Ami, and Evans

10. BSS 17, "Causes of Variation in Chemical Analyses and Physical Tests

of Portland Cement," Bean and Dise

11. BSS 24, "Natural Weathering of Mineral Stabilized Asphalt Coatings

on Organic Felt," Greenfield

12. BSS" 30, "Wind Loads on Buildings and Structures," Marshall & Thom.

13. BSS 31, "Flexural Behavior of Prestressed Concrete Composite Tee-Beams,"

Bryson and Carpenter.

14. BSS 33, "Compressive Strength of Slender Concrete Masonry Walls,"

Yokel, Mathey, Dikkers.

15. BSS 34, "Strength of Masonry Walls under Compressive and Transverse

Loads," Yokel, Mathey, Dikkers.

16. BSS 35, "Interrelations Between Cement & Concrete Properties, Part 5,"

Blaine and Arni.

17. BSS 36, "Interrelations Between Cement & Concrete Properties, Part 6,"

Clifton and Mathey.
18. BSS 37, "The Effect of Moisture on the Heat Transfer Performance

of Insulated Flat-Roof Constructions." Powell and Robinson

19. BSS 40, "Engineering Aspects of the 1971 San Fernando Earthquake,"

Lew, Leyendecker and Dikkers

20. BSS 42, "Design Loads for Inserts Embedded in Concrete," Reichard,

Carpenter , and Leyendecker

.

21. BSS 43, "Paper Honeycomb Sandwich Panels as Lightweight Structural

Components," Reichard.

22. BSS 46, "Building Practices for Disaster Mitigation," Wright, Kramer,

and Culver.

23. "The Relevance to a Constructor," CIRIA Seminar on The Modern Design

oQ Wind-Sensitive Structures, June 18, 1970.

^

24. NASA Technical Memorandum X-53771, August 21, 1968, "Low Level Wind

Gust Amplitude and Duration Study," Dennis W. Camp.

25. AIAA Paper No. 71-136, "Modeling of the Turbulence Structure of the

Atmospheric Surface Layer," by T.R. Sundaram, G.R. Ludwig, and

G. T. Skinner, AIAA 9th Aerospace Sciences Meeting, January 1971.

26. "Laboratory Simulation of the Atmospheric Boundary Layer," by

J. E. Cermak, Presented at Session on Fluid Physics of Pollution,

American Institute of Aeronautics and Astronautics 3rd Fluid and

Plasma Dynamics Conference, 29 June-1 July 1970, Los Angeles,

California, Published in AIAA Jl, Vol 9, No. 9, Sept 1971.

27. ASCE National Structural Engineering Meeting Preprint 1417, "WindTunnel Simulation of Wind Loading on Structures," J.E. Cermak,

and W. Z. Sadeh, April 19-23, 1971.

28. ASCE Journal of the Structural Division Proceedings, Vol 98, No. STl,

Jan 1972., "Drag or Along-Wind Response of Slender Structures," by

B. Vickery and K. Kao

29. ASCE Journal of the Structural Division Proceedings, Vol 94, No. ST7,

July 1968, "New Distributions of Extreme Winds in the United States,"

H. C.S. Thom.

30. ASCE Journal of the Structural Division Proceedings, Vol 94, No. ST6,

June 1968, "Gust Response Factors, "J. Vellozzi, E. Cohen

k 31. ASCE Journal of the Structural Division Proceedings, Vol 93, No ST3,

June 1967, "Gust Loading Factors," A. Davenport.

32. ASCE Journal of the Engineering Mechanics Division Proceedings, EMI,

February 1970, "Aeroelastic Instability of Prisms in Turbulent Flow,"

by M. Novak and A. Davenport.
33. ASCE Journal of the Engineering Mechanics Division Proceedings, EM2

,

April 1970, "Wind Action on Simple Yielding Structures," B.J. Vickery.

34. ASCE Journal of the Hydraulics Division Proceedings, Vol 93, No. HY3,

May 1967, "Similitude Problems in Building Aerodynamics," H.J. Leutheusser,

and W.D. Baines

35. ASCE Journal of the Structural Division Proceedings, Volume 86, No. ST5,

May 1960, Part 1, "Rationale for Determining Design Wind Velocities,

A. G. Davenport

36. ASCE Journal of the Structural Division Proceedings, Vol 96, No ST7

,

July 1970, "Wind Deflections of Tall Concrete Frame Buildings,"

J.F. Wiss, and 0. E. Curth.

37. "An Evaluation of Records of Wind Induced Building Movement in the

1000 Lake Shore Plaza Building (Chicago) ',' by A.G. Davenport, M. Hogan,

BLVJT-3-71, February 1971.

38. "An Analysis of Records of Wind Induced Building Motion and Column

Strain Taken at the John Hancock Center (Chicago) ," by A.G. Davenport,

M. Hogan, B.J. Vickery, BLWT-10-1970 , September 1970.

3 9. "Measurements of Pressure/Velocity Correlation on a Rectangular Prism in

Turbulent Flow," by K.H. Kao , January 1970.

40. "Characteristics of the Mean Wind and Turbulence in the Planetary

Boundary Layer," by H. W. Teunissen, October 1970, UTIAS Review No. 32

41. "Interim Progress Note on Simulation of Earth's Surface Winds by

Artificially Thickened Wind Tunnel Boundary Layers," by R. J. Templin,

Report No. LTR-LA-22, February 26, 1969

42. "A Spire Array for Generating Thick Turbulent Shear Layers for Natural

Wind Simulation in Wind Tunnels," by N. M. Standen, Report No.

LTR-LA-94 , May 1972

43 National Research Council of Canada Technical Translation 1306,

"The Fluctuation of Wind Pressure on the Roof of a House," by

H. Ishizaki and C. Huh, November 1967

44. "Recent Research on Wind Forces on Tall Buildings," by Schriever and

Dalgliesh, Technical Paper No. 298, April 1969

45. "Influence of Wind Pressures on Joint Performance, by Dalgliesh and

Garden, September 1968, DBR/NRC Technical Paper No. 264

46. AGARD Conference Proceedings No. 48, Aerodynamics of Atmospheric Shear

Flows, Munich, Germany, 15-17 September 1969, "Methods and Consequences

of Atmospheric Boundary Layer Simulation," by D. J. Cockrell and

B. E. Lee.
47. "On Simulating the Lower Third of the Urban Adiabatic Boundary Layer in a Wind Tunnel, by N.J. Cook, Atmospheric Environment, Pergamon Press 1973.

Vol. 7, pp 691-705.

48. NPL AERO REPORT 1265, April 1968, "On the Introduction of Turbulence

into Wind-Tunnel Investigations for the Determination of Wind-Induced

Amplitudes of Oscillation," by R. E. Whitbread, Paper presented at the

symposium on Wind Effects on Buildings and Structures at Loughborough,

University of Technology, April 2-4, 1968.

49. Phil. Trans. Roy. Soc. Lond. A. 269, 353-333 (1971), II. Wind Effects on Buildings and Other Structures, Steady and Unsteady Wind Loading of

Buildings and Structures, by C. Scruton and E.W.E. Rogers

50. Symposium on External Flows, 4-6 July 1972, "Some Recent Measurements

of the Flow Around Bluff Bodies in Smooth and Turbulent Streams,"

by p. W. Bearman.

K

51. "The Design of Single and Double Storey Hurricane Resistant Buildings,"

by Captain J.M. Bickford, RE, No. 18, Long Civil Engineering Course,

May 1972.

52. University of Briston, Department of Aeronautical Engineering Report no. NJC 7301

"On Simulating the Lower Third of the Urban Adiabatic Boundary Layer in

a Wind Tunnel," by N.J. Cook

53. BSI CP3: Chapter V: Part 2: September 1972, Code of Basic data for the

Design of Buildings, Chapter V. Loading, Part 2, Wind Loads.

54. "Wind Tunnel Studies at the Building Research Station," by A.F.E. Wise,

D.E. Sexton, Building Research Station

55. "Strain Measurements at the GPO Tower, London," by K.J. Eaton and

J.R. Mayne, BRS

,

56. Building Research Station Digest 99 (second series), November 1968,

Wind Loading on Buildings, Part 1 - The Nature of Wind Loading.

57. Building Research Station Digest 101, Wind Loading on Buildings, Part 2 - The Assessment of Wind Load, January 1969.

58. BRS Digest 105, Wind Loadings on Buildings, (supplement to Digests 99 and

101), "Wind speeds in the United Kingdom," May 1969.

59. BRS Digest 119, The Assessment of Wind Loads (consolidated new edition

of Digests 99, 101 and 105), July 1970.

60. BRS Digest 141, Wind Environment Around Tall Buildings, May 1972.
61. Building Research Station CP 35/70, October 1970, "Wind loading on Vickers Tower, Millbank," by C.W. Newberry, K.J. Eaton, and J.R. Mayne

62. BRS CPl/69, "Instrumentation and Analysis of Full-Scale Wind Pressure

Measurements," K.J. Eaton and J.R. Mayne, February 1969.

63. BRS CP59/68, "Wind Loading of a Tall Building in an Urban Environment - A Comparison of Full Scale and Wind Tunnel Tests," by C.W. Newberry,

K.J. Eaton and J.R. Mayne, August 1968.

64. BRS CP66/68, "The Nature of Gust Loading on Tall Buildings, by

C. W. Newberry, K. J. Eaton, and J.R. Mayne, August 1968

65. BRS CP49/69, "Significant Features of Wind Loading in Relation to the

Design of Structures," C.W. Newberry, December 1969.

66. BRS CP69/68, "A Simple Wind Tunnel for Studying Air-Flow Round Buildings,"

D. E. Sexton, August 1968.

67. BRS CP85/68, "A Review of the Literature on the Structure of Wind Turbulence

with Speckl Regard to its Effect on Buildings," M.E. Jones, December 1968.

68. NPL Aero Report 1258, March 1968, "Simple Wind Tunnel Design," by

P. Bradshaw.

69. NPL Aero Report 1264, April 1968, "Some Effects of Turbulence on the

Flow Around Bluff Bodies," by P. W. Bearman

70. NPL Aero Report 1247, October 1967, "The Application of Maskell's Theory

of Wind-Tunnel Blockage to Very Large Solid Models," by C.F. Cowdrey

71. NPL Aero Note 1055, May 1967, "A Siaple Method for the Design of WindTunnel Velocity-Profile Grids," by C.F. Cowdrey

72. NPL Aero Special Report 028, June 1969, "Measurements of Aerodynamic

Forces on the Northumberland Park Tower," by C.F. Cowdrey.

(73. NPL Aero Special Report 001, October 1967, "An Investigation of the

Aerodynamic Stability of a Model <xf .the Proposed Tower Blocks for the

World Trade Center, New York, Part II Further wind-tunnel studies

relating mainly to the response of the towers blocks to turbulent

winds," by R. E. Whitbread.

74. NPL Aero Report 1296, April 1969, "An Investigation of the Forces on

Flat Plates in Turbulent Flow," by P. W. Bearman.

75. BSS 48, "Design, Siting, and Construction of Low-Cost Housing and

Community Buildings to Better Withstand Earthquakes and Windstorms,"

B. Reps and E. Siraiu.

APPENDIX D

HOUSING AND WIND PROBLEMS IN THE

NORTHERN CARIBEAN AND INDIAN OCEAN COUNTRIES

D-1

LOLiJ-COST HOUSING AND EXTREI^E WIND-RELATED (^ROBLEHS

IN JAMAICA AND THE NORTHERN CARIBBEAN ISLANDS

REPORT

FOR

NATIONAL BUREAU OF STANDARDS

AND

UNITED STATES AGENCY FOR INTERNATIONAL DEl/ELOPnENT

' INUESTIGATION OF WIND RESISTANCE OF

LOW-COST HOUSES'

A. D. Adams

Consulting Engineer

Jamaica

nay, 1974

- 1 -

C 0 N T E N T S

SECTION ITEPI PAGE NO .

CONTENTS 1-2

1.0 SCOPE 3

2.0 LiniTATIONS AND A5SUP1PTI0NS 3-4

2.1 General 3-4

2.2 Building Size Considered 4

3.0 LOy-COST HOUSING TRENDS AND THEIR DESIGN

PROBLEHS 4-6

3.1 Trends in Loui-Cost Housing 4-5

3.2 Design Problems 6

4.0 THE INFLUENCE OF SOC lO-ECONOniC CONSIDERATIONS

ON HOUSING PATTERNS 6-10

4.1 The Influence of Tradition and Social

Changes S-8

4.2 Other Relevant Socio-Economic

Considerations 8-10

5.0 HOUSING NEEDS AND PROGRAHS FOR THE NEXT TEN

YEARS 10-17

5.1 Projected Housing Needs 10-12

5.2 Housing Programs 12-18

5.2.1 Sites and Services Project 12-13

5.2.2 National Housing Corporation, Jamaica 14

5.2.3 Other Government Housing Schemes 14-17

6.G CLinATOLOGICAL DATA AND WIND DAPIAGE RECORDS 17-30

6.1 Topography of Jamaica and its Effects

on the Wind Climate 17-19

b.1.1 Topography 17

6.1.2 Climate 17-19

6.2 Wind Speed Records 19-29
C 0 NT E NTS

SECTION ITEPI PACE NO .

6,3 Wind Speed for Structural Design 29-30

7.0 WIND DAMAGE 30-31

8.0 SOLUTIONS FOR P1ITIGATING LOSSES DUE TO

HIGH WINDS 31-33

- 8.1 Warning System and Precautionary

Measures 31-32

8.2 Structural Provisions 32-33

8.2.1 General 32

8.2.2 Roofs 32-33

8.2.3 Walls 33

8.2.4 Glazing 33

9.0 ^ LOW-COST BUILDING DESIGN PROBLEMS UNIQUE

TO JAMAICA 33-34

9.1 Building Codes and Standards 33-34

9.2 Structural Problem Areas 34

10.0 CONCLUSION 34

11.0 LIST OF REFERENCES 35-37

APPENDIX I

**«*«*««*•««**•*»•*«»*•«*« *«««*
LOlil-COST HOUSING AND EXTREPIE-liJIND-RELATED PROBLCnS

IN JAMAICA AND THE NORTHERN CARIBBEAN ISLANDS

by A. D. Adams

Consulting Engineer, Jamaica

0 SCOPE

This report identifies lou-cost housing trends and

their design problems in Jamaica and the Northern

Caribbean and discusses the influence of socio-ecoRotn'ic

considerations on housing patterns.

It also presents an analysis of housing needs in

the next ten years.

It tabulates climatological data on extreme winds

and vjind damage statistics and also studies the applicability of alternative solutions for mitigating losses

from high winds.

Finally, it defines possible low-cost building

design problem areas unique to Jamaica.

0 LIMITATIONS AND ASSUMPTIONS

1 General

This is the second of two reports. It attempts to

restrict consideration to those aspects of housing

specifically related to wind resistance. More general

information is introduced only where it is intended to

fill some gap in the Report No. 1 which is attached as Appendix I.
LIMITATIONS AND ASSUMPTIONS CONTD.

General contd.

Problems of communication have severely restricted

the gathering of data on the other Northern Caribbean

Islands. However, the other English speaking Caribbean

Islands have similar socio-economic and technical background to Jamaica and can be assumed to have generally

similar conditions with respect to low-cost housing

except where specifically stated otherwise.

Building Size Considered

Following decisions reached at the Workshop

Conference on "Development of Design Criteria and Hethodology for Low-Rise/Low-Cost Buildings to Better Resist

Extreme Winds", held in Manila in November, 1973, consideration has also been restricted to 'low-rise' buildings

LOW-COST HOUSING TRENDS AND THEIR DESIGN PROBLEMS

Trends in Low-Cost Housing

There is a continuing trend towards building

"low-cost" single storey houses in hollow concrete-block

masonry and with corrugated metal roofing on timber

rafters. The structural systems are described in detail

in Appendix I, page 5.

For two and three storey buildings, masonry construction is equally popular but the roofing systems are

quite often of reinforced concrete slab.

Large panel precast concrete systems do nQ.t at

present fall within any accepted definition of "low-cost

housing" but are capable of doing so where increased

density and a lower standard of finishes and amenities

is accepted. This system is being used in increasing

numbers

.
- 5 -

3.0 LOht-COST HOUSING TRENDS AND THEIR DESIGN PROBLEDS CONTD.

3.1 Trends in Low~Co8t Housing contd.

The following tables shoui the classification of

total dwellings by materials of the outer walls taken

27

from a 1970 survey

There is no breakdown of these figures into lowincome housing and others. However, the same survey

shows that over three quarters of all dwellings were of

three room or less and over half {63%) were two rooms

or less.

TABLE 3.1.1 - DWELLINGS CLASSIFIED BY HATERIAL OF

OUTER WALLS

(3APIAICA)

Total

Dwellings

MATERIAL OF OUTER WALLS

Wood Concrete Stone Brick Nog Wattle/

Adobe

Other

420,159 155,197 182,349 9,354 3,571 49,417 16,908 3,363
LOlri-COST HOUSING TRENDS AND THEIR DESIGN PROBLEWS CONTDo

Trends in Low-Cost Housing contd.

TABLE 3.1.2 - PERCENTAGE DISTRIBUTION OF DUELLINGS

BY TYPE OF MATERIAL OF OUTER WALL

(OAPIAICA)

rtat-erial of Outer liJall Total Urban Rural

TOTAL 100.0 100.0 100.0

Concrete 43.4 59.3 30.4

Wood 36.9 30.4 42.2

Nog 11.8 7.2 15.5

Stone 2.2 0.7 3.5

Uattle/Adobe 4.0 0.7 6.7

Brick 0.9 1.3 0.5

Other 0.8 0.4 1.1

Design Problems

Design problems are related mainly to the provision

of roof fixings to resist high •local' wind effects.

These and other problems are also discussed in

detail in Appendix I, page 14.

THE INFLUENCE OF S0CI0»EC0N0f1IC CONSIDERATIONS ON HOUSINu

PATTERNS

The Influence of Tradition and Social Changes

In Jamaica, traditionally , homes for low-income

groups in urban areas were mainly high density apartment

buildings or "tenements", consisting of terrace-houses or small groups of closely clustered houses. There would

generally be a communal yard with shared facilities.
7

4.0 THE INFLUENCE OF SOCIO-ECONOmC CONSIDtlRATIONS ON HOUSING

PATTERNS CONTO.

4.1 The Influence of Tradition and Social Changes contd.

On the other hand, the middle incoree group invariably

preferred detached housest with the greater privacy this

offered. The aspirations of all upwardly-mobile members

of the low-incorae group, therefore, tended toward the

middle income preferences i.e. detached houses.

Uith the widespread introduction of mass housing

development some ten to fifteen years ago, this preference

has forced developers to build detached houses and often

to make lots very small in order to achieve a low selling

price.

The continuing pattern of low-cost housing, thereforo^,

has been urban housing developments consisting of hundred©

of closely spaced single-storey, detached dwelling-unite.

It should be noted that in the middle income group,

a developing counter-trend is toward a preference for

self-contained "apartment type" dwelling units often in

blocks of flats.

This is a reaction arising partly from fear of

increasing urban crime and thus seeking safety in more

compact numbers.

This phenomenon does not affect the lower income

group to the same extent, but it Is observed that aspiring

ambers of this group tend to follow the lead of the

middle Income group. It is felt, therefore, that we may

be about to experience a change in the preferences of

thia lower incoMa group which will now show greater

acceptance of multi-atorey and terraced naaa-houaing.
THE INFLUENCE OF SOCIO-ECONOWIC CONSIDERATIONS ON HOUSING

PATTERNS CONTD.

The Influence of Tradition and Social Changes contd.

On strictly economic grounds, this should rationalise

the use of limited financial resources and might accelerate

the present rate of lou-cost housing construction.

As far as wind resistance is concerned, the relevant

aspect of all this is that the current pattern of large

clueters of closely spaced single storey concrete buildings,

with pitched lightweight roofs, will probably soon be

Joined by an increasing number of low-rise and high-rise

rectangular concrete buildings with flat roofs.

Other Relevant Socio-Econoroic Considerations

Jamaica's population is approximately two million

persons with a rate of natural increase of approximately

5

27 persons per 1000 .

Out of a total labour force excaedlng 800,000,

approximately 20 - 25% are unemployed .

The construction and installation Industries employ

approximately 7% of the employed labour force^.

At the end of 1972, the personal income per head

of population was approximately 3$500 (US|550)^.

Examples of daily wage ratea in the construction

industry are:-

2

Unskilled labourers - 3$5.00 (US$5. 50)

Skilled workers e.g. Carpenters, ^ Operators - 3$7.00 - 3t9.00

(US|7. 70 - US$9.90)

The following are statistics obtained from a survey

27

in 1970 and refers to the total housing stock

t

/'
- 9

4 . 0 THE INFLUENCE OF SOC lO-ECONOniC CONSIDERATIONS ON HOUSI NG

PATTERNS CONTD.

4.2 Other Rslsvant Soc io-Econom ic Considerations contd.

TABLE 4.2.1 - DUELLINGS CLASSIFIED BY TYPE

(3AnAICA)

TYPE OF DWELLING

Duellings

Separate

House

Flat/

Apartment

Barracks

OutRoom

Part

of COD- m er- cial

Building

)ther

Private

Group

Dwelling

No

Fixed

^bode

^ot

Stated

420,159 327,656 57,083 3,223 i,069 11,765 3,886 247 65 2,165

TABLE 4.2.2 - PERCENTAGE DISTRIBUTION OF DWELLINGS

NO. OF Roons

( DAHAICA)

No. of Rooms Total Urban Rural

TOTAL 100.0 100.0 100.0

1 32.7 42.3 24.9

2 26.3 19.6 31.7

3 16.1 11.7 19.7

4 8.5 7.5 9.3

5 5.3 5.9 4.9

6 2.8 3.3 2.4

7 2.6 3.4 1.9

8 or more 5.8 6.3 5.3
- 10 -

THE INFLUENCE OF SOC IG-ECOI\IOWIC CONSIDERATIONS ON HOUSINQ

PATTERNS CONTD.

Other Relevant Socio-Economic Considerations contd.

TABLE 4.2.3 - PERCENTAGE DISTRIBUTION OF DWELLINGS BY

TYPE OF TENURE

Type of Tenure Total Urban Rural

TOTAL 100.0 100.0 100.0

Owned 52.4 29.7 70.8

Leased 2.5 3.9 1.4

Rented 36.5 59.9 17.6

Rent-Free 7.9 5.8 9.6

Squatted 0.4 0.5 0.3

Other 0.3 0.3 0.3

HOUSING NEEDS AND PROGRAWS FOR THE NEXT TEN YEARS

Projected Housing Needs

The housing situation has always been characterised

by the inadequacy of new housing to roeet the growing

demand. It is estinated that between 1960 and 1970 some

32,200 new units were added for an Increase in households

of some 60,000^.

A projection of total housing needs for the next ten

years is as follows;-
11

5.0 HOUSING NEEDS AND PROGRAHS FOR THE NEXT TEN YEARS CONTDo

5.1 Projected Housing Needs contd.

TABLE 5.1.1 - PROJECTED HOUSING NEEDS 1975 - 1985

TYPE OF NEED 1975-1980 1980- 1985

New Households 9,700 10, 800

Obsolescence (replacement) 4,700 5, 200

Total av/erage annual need 14,400 16, 000

Total housing at end of

period 519,000 571, 000

The above total projected housing needs are based

on an estimated population increase of 195,300 persons

and 215,500 persons for the periods 1975-1980 and

1980-1985 respectively and an average household size of

4.0 persons per household. It is also estimated that

total housing stock at the end of 1975 will be about

470,000.

No precise figures exist on the current existing

housing stock but in 1970, this was estimated to be

26 13

between 420,000 and 434,000

The problem of housing shortage is greatest in the

urban areas, mainly due to population increase and internal

26

migration. It has been observed that between 1960 and

1970, the rural population has remained approximately the

same in numbers, while population increases have been

concentrated in urban areas. Overall, the population

increased by 16^ during this period, while the number of

dwellings increased by only 5%.
12 -

5.0 HOUSING NEEDS AND PROGRAMS FOR THE NEXT TEN YEARS CONTD.

5.2 Housing Programs

5.2.0 Housing is provided by both the public and private

sectors but by and large, the private sector provides

housing for middle and upper income groups, while the

Government restricts its activities to constructing

houses for lower income groups.

Even so, only a small percentage of the Government's

efforts were directed at the very bottom of the lower

income scale and families in this category were often

forced into squatting, shanty towns or overcrowded

households.

5.2.1 Sites and Services Project

In 1972-3 the Ministry of Housing developed a programme to cater to the needs of families with an income of 3|1,200 or less per annum (between 60-70 per ceni:

of the population). Since 1973 this income ceiling has

been increased to 3Sl,500. This programme, called th@

Sites and Services Project, provides basic infrastructure

development and community facilities, and a minimum

'core' dwelling unit.

In addition, it provides for the development of

community organizations, employment and skill training

5

programmes and the maintenance of stable property values ^

This project aims at providing 6,000 serviced lots

during the next three years. Two-thirds of these will be

located in the Kingston netropol i tan Area and the

remainder shared between the smaller urban centres.

28

Lots are available in three options
13

5.0 HOUSING NEEDS AND PR0GRAP15 FOR THE NEXT TEN YEARS CONTD,

5.2 Housing Programs contd.

5.2.1 Sites and Services Project contd.

Option 1

To be provided with lot-services and connections

for electricity, water-supply and sewerage and materials

for core shelter and enclosure. The core comprises toilet,

shower and kitchen space.

Option 2

To be provided with lot-services and connections,

a built core and materials for shelter and enclosure of

the remainder of the house. The sheltered area will be

approximately 180 square feet.

Option 3

To be provided with lot-services and connections,

a built core and shelter and materials for construction

of an enclosure for the rest of the house.

This idea is to harness the self-help capabilitioe

and inclinations of the prospective home-owners who e?s

also largely under-employed.

Ownership of serviced lots will be on a leasehold

basis. However, an inheritance clause will form part cf

the leasehold agreement.

Selling prices of the various options will vary

between JSl ,900 and $2,^00. Loans for materials will be

available through credit unions.

This project is administered by a special division

within the Plinistry.
14 -

5.0 HOUSING NEEDS AND PROGRAWS FOR THE NEXT TEN YEARS CONTD.

5.2 Housing Programs contd.

5»2>2 National Housing Corporation, Jamaica

In 1973, the National Housing Corporation, a statutory body, was formad uith the purpose of executing

"profit-earning" middle-income housing projects and to

undertake renewal and land development projects. The

Corporation's eventual profits, would revert to the

Ministry of Housing and could be used for low-income

housing. The first project by this Corporation, consisting

of 1,050 two and three bedroom units costing between

$14,000 and $18,000 will commence in Dune, 1974.

5.2.3 Other Government Housing Schemes

The emphasis in the Government's low-cost housing

programs is being shifted to the Sites and Services

project mentioned above. However, the Five-Year Plan for 1970

proposed certain Government Housing Schemes concentrated

in the low-income areas for persons not able to afford

private housing.

c s For the 1970/71 - 1974/75 period, these are

summarised as follows (Figures in parentheses show number

29

of units completed between 1970 and 1973) :-

(a) Government-built Housing - Provision of low-co,8t

housing, either for sale on 5^ deposit and 25-yaar

mortgages or to be rented at subsidised rates, to

be built, by privets contractors under the supervision of the ninistry of Public Utilities and

Housing, on government owned land in both urban and

rural areas. Selling prices have been between

$2,000 and $3,000 excluding eubsidies. Total

units: 3,125 (1902) .
15 -

5.0 HOUSING NEEDS AND PROGRAnS FOR THE NEXT TEN YEARS CON.TD,.

5.2 Housing Programs contd,

5.2.3 Other Government Housing Schemes contd.

^b) Owner-Occupied Schemes - Loan assistance to persona

in rural areas who own or have long-term lease on land and who can afford to pay for their homes; a capital subsidy of up to one-third is offered and

no deposit required; administered by the ninistry

of Public Utilities and Housing. Costs have bean

about $2,600 excluding subsidies. Total units:

3,600 (829).

(c) Urban Renewal - Urban renewal and rehousing to

alleviate the problem of overcrowding and substandard housing in Kingston; administered by the

ninistry of Public Utilities and Housing. Total

units: 4,876 (619).

(d) Rural Housing Project - Provision of adequate

housing to farmers through construction of new

units and additions and repairs to existing units

with subsidies of 50^ and 3Z^/Z% and the balance

of cost to be repaid by the farmer; to be administered

by the ninistry of Rural Land Development. Costs

have been about $360. Total units: 4,880 (960).

(e) Indigent Mousing - Housing ^nlts erected free of

charge on land owned by the allotae and grants made

to Improve existing dwellings; adniniatered by the

ninistry of Local Government. Prices have been about

$500 excluding subsidies. Total units: 2,250 (1272).

(f) Aided Self-Help Scheme - Response to this program

has been unenthusiastic and it has been decided to

phase it out.
16

5.0 HOUSING NEEDS AND PROGRAPIS FOR THE NEXT TE N YEARS COWTD,

5.2 Housing Programs contd.

5.2.3 Other Government Housing Schemes contd.

(f) Aided Self-Helf Scheme contd.

Assistance was furnished to organizations whose

members had been saving for housing with Government

acquiring land, providing infrastructure, housing

materials and technical assistance, and the labour

to be contributed by the prospective residents.

Feu or no units are expected to be developed during

the plan period.

(g) Assistance to Housing Co-operatives - Official

policy is to encourage growth of co-operative

housing ventures and the Plutual Housing Services

Company, a non-governmental, non-profit organization,

has the power to acquire, hold and dispose of land,

enter into contracts, receive and disburse funds,

and organise and manage co-operatives housing

societies. Its activities are expected to attract

to the field of low-income housing some of the

investment that normally flows to higher income

developments. Prices to date range between $4^000

and $7,000. Total units: unknown.

The total number of the government built or aided

units described above under Section 5.2.3 Is about

18,700 for the 1970/71 - 1974/75 period which, against

a total of 58,000 units required for the country, leaves

a balance of 39,700 units to be constructed by the

private sector if a new house is to be provided for

every new household and obsolescent units replaced. The

average annual number of government units projected for

the five years is about 3,750, a substantial increase over

the 1969/70 figure of 858 units and 1968/69 figure of 1,354

units acutally built.
- 17 -

5.0 HOUSING NEEDS AND PROGRAHS FOR THE NEXT TEN YEARS CONTD.

5.2 Housing Programs contd.

5.2.3 Other Government Housing Schemes contd.

(Note: The actual performance for 1970-73 has been 1,937

29 units per annum)

Government programs which provide assistance in

improving existing duellings as well as private re- habilitation may reduce the deficiency in the replacement of obsolescent housing.

6.0 CLIPIATOLOGICAL DATA AND liiIND DAHAGE RECORDS

6.1 Topography of Jamaica and its Effects on the Utind Climate

23 6.1.1 Topography

Of a total land area of about 4,400 square miles,

almost half of Jamaica is over 1,000 feet above sea l9v@.l

and about 40 square miles above 5,000 feet.

The three main types of land forms of the islend

are

(1) The interior mountain ranges

(2) The dissected limestone plateaux and hills

(3) The costal plains and interior valleys.

The interior mountain ranges form the spine

of Jamaica and are highest and most rugged In the

east where the Blue l*lountains attain over 7,000 feet

(See Figure 6.1.1).

6.1.2 Climate

The Northern Caribbean lies between the subtropical high pressure and equatorial low-pressure belts

of the Atlantic where the north-east winds blow regularly

throughout the year.

19 -

6.0 CLIWATOLOGICAL DATA AND UIND DAnAGE RECORDS CONTD.

'6.1.2 Climate contd.

In Oamaicat these prevailing winds are modified in three

major respects: because of the high Blue Clountains in

the east of the island, the trade-winds swing around

St. Thomas to strike the Kingston Area from an east

and east-south-east direction; alternating sea breezes

and land breezes occur daily and occasional cold fronts,

reach Jamaica from the American Plainland. The lower

o o elevations are generally warm with a range of 70 - 90

approximately. Temperatures are 10° - 20° cooler in the

highlands.

Hurricanes are a perennial threat to Jamaica. An

analysis of Caribbean hurricanes and tropical storms

between 1886 and 1967 shows that 19 had tracks which

directly hit Jamaica and 98 (ofwhich 48 were of hurri^9f>e

force) had centres within 150 miles of the island. Abput

23 one-third of these storms caused flooding and damage

Figure 6.1.2 shows the tracks of major hurricanes

affecting Jamaica from 1880 - 1970 and Table 6.1.3 shows

the actual dates of occurrence of storms from 1886 - 1967.

6.2 tiiind Speed Records

Prior to 1950, wind speed recordings were by

"Robinson" anemometer (Uind-run Integrator). The

capacity of these were limited (approximately 105 knots)

and published Meteorological Office records for this

period do not provide actual wind speeds but classify

storms as either hurricanes (i.e. winds exceeding 73

miles per hour ) or tropical storms (See Table 6.1.3).
- 20 -

6.0 CLinATOLOGICAL DATA AND UlIND DAPIAGC RECORDS CONTD,

MAJOR HUBRICANES AFFECTING JAMAICA

1880- f970

c

o

9o

HURRICANE TRACK

50 100 _J I I MILES

Figure 6.1.2
- 21

6.0 CLinATOLOGICAL DATA AND UIND DAMAGE RECORDS CONTD.

TABLE 6.1.3 - HURRICANES AND TROPICAL STORES WITH

CENTRE PASSING WITHIN 150 MILES OF

3AP1AICA^^

H = Hurricane

T = Tropical Storm

Date

«

Hor

T

Minimum

Distance of

Centre from

Damaica

1

Direct

Hit

Track

across

Island

Effects on Damaica

Dune 1886 H 90 miles S.UJ.

August loob Mn August 1886 H 15 miles U.

damage » Fit

Sept. 1886 H E - N.E. Damags

Hay 1887 T 15 miles bJ. Duly 1887 H 150 miles S.S.Iii.

August 1887 T 60 miles N.E.

Sept. 1887 H 100 miles S.S.til.

Oct. 1887 T 120 miles W.N.W.

Oct. 1887 H 120 miles N.N.E

Sept. 1889 H 70 miles S.W. Flooding

Oct. 1891 T 90 miles N.N.E.

(or most nothsern part) Flooding

Nov. 1893 T 80 miles W.

Sept. 1894 H 120 miles N.N.E.

August 1895 H 30 miles S. by U.
- 22 -

CLIflATOLOGICAL DATA AND UIND DAflAGE RECORDS CONTD.

TABLE 6.1.3 contd.

Date

»

itMor

T

nin itnum

Distance of

Centre from

Dama i ca

ui r ec t Hit

Track

across

Island

Lit ec ts on Jamaica

n

III Clil uamage

Sept. 1896 H S - SSW Damage

Duly 1896 H 150 miles NliJ of Wrn. tip

Oct. 1898 T S - SSW

Oct. , Nov. 1898 T 20 miles S

Sept. 1900 T 90 miles N by E 1901 T 125 miles Slil 1901 T 80 miles N by liJ August 1903 H E - NU Piajor

Hurricane

June 1904 T tilsstern

fin

Severe

r xoouxny xn UCb. X^UH T1 3U nilx B8 lU

U.C u . X 7 U 9 un

"tn ou mnij.xes { 1 oa rc n ni AAA

9 ep w . A 7U D T1 x*tu imxes j\u

Oct. 1906 H 100 miles S by bJ Mnw 1 qnin T

June 1907 T 100 miles lil by 5

Sept. 1908 T 150 miles NE of

East tip

3uly 1909 T 20 miles SU

August 1909 T 60 miles S by U

August 1909 H 40 miles NE

Sept. 1909 H 110 miles Slii
23

CLIPIATOLOGICAL DATA AND UIIMD DAPIAGE RECORDS CONTD.

TABLE 6.1»3 contd.

Date

«

. Hox

T

nininiuni

Distance of

Centre from

Jamaica

Direct

Hit

Track

across

Island

Effects on Jamaica

Oct. 1909 H 120 miles SW

Nov. 1909 T 125 miles SE Severe Flooding

August 1910 T E-Central-U

Sept. 1910 H 10 miles N Damage

Oct. 1911 T 35 miles N

Oct. 1912 T 60 miles SU

Oct. 1912 H Id - NU Major Hurricane. ExtenaivQ

flooding

August 1915 H 15 miles N Noteuor thy

damage. Flooding

Sept. 1915 H 80 miles U by 5

Sept. 1915 H 90 miles S by bJ Severe hurrA

cane. Flooding

August 1916 H SE-CentralNU

Ha jor

hurricane

August 1916 H 15 miles 5 by lii Damage. Flooding

Oct. 1916 H 60 miles S Damage. Flooding

Sept. 1917 H 35 miles N of

Nlil coast

Damage

August 1918 T 55 miles SU

August 1918 H 120 miles 5 by y

Oct. 1923 T 140 miles U

Nov. 1924

Oct. 1926

T

T 140 miles SU

S by NN by E

Oct. 1927 T 80 miles UNU

Sept. 1928 T Southernmost tip
- 2A -

CLIWATOLOGICAL DATA AND liJIND DAHAGE RECORDS CONTD.

TABLE 6.1.3 contd.

Data

*

H1 t or

T

flinimum

Centre from

Jamaica

Direct

Hit

Track

across

T a 1 o n rf 1 o X a 1 1

U

Effects on

waHi a X ^ Q

Sapt. 1930 T 140 miles N by E AuQust 1931 T1 14Q miles bv lii Sept. 1931 T 60 miles SSU

Sept. 1931 T E-Central-k

Sept. 1932 T E - SE

Nov. 1932 H 125 miles WNy Damage (?)

Duly 1933 H 55 miles SU Flooding

Duly 1933 T U Coast

(Grazing)

Flooding

August 1933 T 20 miles SU Severe

Flooding

Sept, 1933 H 80 miles Slii Oct. 1933 H 120 miles \ii Flooding

Oct. 1933 T SU by SMi|i hv N Flooding

Oct- 193A T1 m by N

Sept. 1935 H 35 miles liJ Damage

Oct. 1935 H 40 milas E) Damage. Flo(

Oct. 1935 T 45 miles Nlil) August 193B H 40 miles SU Damage

AuQust 1938 H 105 miles SSU

Nov. 1939 T 40 miles N

August 1942 H 120 miles Shi Sept. 1942 T 20 miles S

Oct. 1942 T 60 miles NE

August 1944 E-Central-W Extensive

damage most!

on north
- 25

CLIWATOLOGICAL DATA AND liJIND DADAGE RECORDS CGNTD.

TABLE 6.1.3 contd.

Date

Hor

1

ninimum

Distance of

Centre from

Jamaica

Direct

Hit

Track

across

Island

Effects on Jamaica

August 1944 T 95 miles S

Oct. 1944 T 110 miles 111 by N Sept. 1947 T 40 miles NIJ

Play 1948 T 150 miles E by S • Heavy Rain

Sept. 1948 T 30 miles U

Oct. 1949 T stij top-Ny

Oct. 1950 H 49 miles ItlNlif Damage

August 1951 H 5 miles SSliI "Charlie"

very extent

sive damage

in aouth

Sept. 1953 T 50 miles S

T1 140 miles NU

Oct. 1954 H 100 miles E by S

August 1955 T 100 miles U by S

Sept. 1955 H 90 miles NU

Sept. 1955 H 150 miles SU)

Sept. 1958 H 100 miles NE

Sept. 1958 T 80 miles NE

Oct. 1963 H 115 miles NE and

100 miles NNW

"Flora" sevj

flooding in

east

August 1964 H 70 miles NE "Cleo" No

damage

Sept. 1967 H 75 miles ESE "Beulah" No

damage
26

CLinATOLOGICAL DATA AND lilIND PARAGE RECORDS CONTD.

Mind Speed Records contd.

The Caribbean Pleteorological Institute are due to

issue soon, a publication, "The Climate of 3aaiaica" by

the Jamaica fleteorological Institute. This will gix/e

30-year means for this period, based on the "Robinson"

instrument

.

From 1950 to 1962 recordings were made by "Dines"

pressure-tube anemographs. Since 1962, the recording

instrument used has been a 3-cup-anemometer with an in25 line transmitter . Records are taken for meteorological

purposes and observations conform with guidelines set by

the World Fleteorological Organization.

There are at present, eight wind-speed recording

stations in operation in Damaica, maintained by the

Jamaica neteorological Office. Of these, only two,

Palisadoes (20 years) and flontego Bay (12 years) are of

relatively long-period. The others at Bodies, Crawford,

Rason River, Smithfield, Luana Point and Clorant Point,

25 have been in existence for 2 years or less . In San 3uan,

21

Puerto Rico, such recordings extend back to 1940

Figure 6.2.1 shows the location of the existing

recording stations in Jamaica.

H. C. S. Thorn has established that, using the

highest average monthly mean wind speed \l , and the mean

m number of tropical storms per year, f, it is possible

21

to make reasonable estimates of extreme wind distribution

The following Table 6.2.2 shows data required,

obtained from two stations in the Northern Caribbean for

the calculation of extreme wind distribution.

- 28

CLIWATOLOGICAL DATA AND lilIND DAWAGE RECORDS CONTD.

Uind Speed Records contd.

This data was compiled and analysed by the Caribbean

nataorological Institute, St. Dames, Barbados, liJ. I.

TABLE 6.2.2 - DATA REQUIRED FOR ESTIflATION OF EXTREME

WIND DISTRIBUTION

STATION Vm PERIOD P f Pt

mile/hour

Palisadoes,

Jamaica 13.4 1950-62 51.7 1.1 0.22

San Duan,

Puerto Rico 12.9 1940-55 50.5 1.2 0.27

^ is a scale parameter

P^ is the probability of an annual extreme wind

being produced by a tropical storm.

Thorn's work refers to 'fastest mile' wind speeds

as used in the U. S. A.

The following are Fastest nils speeds for various

return periods for two stations in the Northern Caribbach

derived by H. C. Shellard of the Caribbean Plstaorological

21 Institute .

TABLE 6.1.3 - FASTEST RILE SPEEDS (HPH) FOR RETURN

PERIODS OF 10, 20, 25, 50, 100

STATION 10 20 25 50 100 200 yrs.

Palisadoes, Damaica 71 79 83 93 105 117

San Duan, Puerto Rico 72 80 83 94 105 118
29

6.0 CLinATOLOGICAL DATA AND IJIND DAHAGC RECORDS CONTD.

I 6.2 Uind Speed Records contd.

blind speed recordings in Damaica and the Coremonwealth

Caribbean are not generally based on the fastest mile of

wind but rather on the British practice of extracting the

highest hourly mean speed and the highest gust speed for

each day^^.

Three-second gust speeds are used in the Commonwealth

Caribbean and the following relationship has been estab21

lished for converting fastest mile speed, to gust

speed, g.

g = 1.09v + 8 m.p.h.

Table 6.2.3 shows maximum gust speeds corresponding with

the fastest mile speeds shown in Table 6.1.3.

TABLE 6.2.3 - flAXIPIUPI GUST SPEEDS (HPH) FOR RETURN

PERIODS OF 10, 20, 50 AND 100 YEARS^^

RETURN PERIOD

STATION 10 20 50 100

Palisadoes 85 94 110 123

San 3uan 87 95 111 123

6.3 Uind Speed for Structural Design

21

H. C. Shellard and the draft Barbados Association

of Professional Engineers' Code "Uind Loads for Structural

Design" ha\/e recommended a basic wind speed of 120 mph for

design purposes. This is a (3-second) gust speed at 10

metres height above ground, recommended for a return

period of 50 years.
- 3C -

CLIFIATOLOGICAL DATA AND UIND DAHAGE RECORDS CONTD.

lillnd Speed for Structural Design cantd.

A similar speed ie proposed for the Birtish V/irgin

Islands in the North Caribbean.

Factors are also proposed in the Barbados Association

of Professional Engineers' Code for topography, ground

roughness, building size, height above ground and estimated

building life. These factors are identical to those used

in the British Code of Practice No. 3; Chapter U; Part 2:

Itlind Loads and are derived from work done by Dr. K. Eaton

of the Building Research Station, U. K.

WIND DAHAGE

Although hurricanes are frequently generated in th®

Caribbean Area, most of the islands are comparatively

small in size and an examination of records for any

individual island, will show much less frequent instsnces

of direct hits. For instance, Jamaica is only 150 miles

by 50 miles in size and Table 6.1.3 shows the infrequency

of direct hits when compared with the number of tropical

storms which pass within 150 miles of the island.

The most recent wind damage information available

for Jamaica, dates back to 1951, the year of the last

direct hit. Newspaper reports indicate that damage was

estimated at USS56 million at 1951 prices. Twenty thousand

buildings were destroyed and 150 people died. Gust speeds

were 125 m.p.h. (Life nagazine 1951). Twanty-five thousand

people ware left homslese, and in one parish (St. Thomas).

90-100^ of homes were destroyed in 15 communities (Daily

Gleaner August 19-31, 1951).
- 31 -

7.0 liiIND DAWAGE CONTD.

It should be noted that up to the time of the hurr.l-'

cane, the large majority of low-income houses were wooden,

with roofs of corrugated iron on wooden rafters and of

generally poor construction. Such buildings suffered

badly and most of the recorded wind damage occurred to

such structures. Light roofs on all types of buildings

suffered similarly but wooden shingles performed quite

well

A report on Hurricane Betsy which hit Nassau,

16

Bahamas in 1965 , records that maximum wind speeds of

85 knots did relatively little damage. Neither wooden

buildings nor buildings with concrete block walls suffered

much. Asphalt shingles sustained widespread damage but

wooden shingles survived quite well.

One devastating side effect of high winds in the

Caribbean is flood rains. Flood rains often accompany

near-misses as well as direct hits of hurricanes on the

island and therefore, occur with far greater frequency.

8.0 SOLUTIONS FOR fllTIGATING LOSSES DUE TO HIGH UINDS

8.1 h/arninq System and Precautionary fleasures

Adequate hurricane warning system and speedy dissemination of instructions for the public has proven of great

value in the past.

In Damaica, the fleteorologlcal Office and radio

stations have co-operated to issue frequent new-bulletins

as any hurricane shows signs of being a threat to the

island. Precautions are published in newspapers throughout

the usual hurricane season (June - September) and repeated

on all other news media when a specific threat arises.
- 32 -

SOLUTIONS FOR WITIGATING LOSSES DUE TO HIGH WINDS COWTDo

liiarnlnq System and Precautionary fleasures contd.

Precautions include storing water and fuel, battening

windows and doors, securing loose or moveable outdoor

items or fixtures and strengthening defective windows,

doors or roofs.

Structural Provisions

General

Where good practice as defined by either local

regulations or accepted standards is observed, damage

is usually greatly minimized. All attempts to mitigate

losses should, therefore, commence with procedures to

ensure strict adherence to accepted standards and adequatiB

inspection during conetruction.

In Damaica, the registration of engineers and

architects is being considered for implementation. This

and/or strong, well-staffed local building authorities

would help to ensure good standards.

Roofs

lilind damage to roofs is usually due to high local

uplift forces. Damage is mainly to lightweight roofing

and is greatest for metal sheeted roofs.

Inadsquate fastening to sheeting, especially roof

corners, edges and ridge, is the main cause of failuresc

Uith thin sheeting, the size of washers also play an important part.

The solution to this problem is for engineers to

design the fastening of roof coverings for actual local

suctions obtained by reference to appropriate wind codes

or research data.
- 33 -

8.0 SOLUTIONS FOR PlITIGATING LOSSES DUE TO HIGH UINDS CQUJ t

8.2.2 Roofs contd.

Complete removal of the roofing structure occasionally

occurs and is usually due to a lack of straps or holding

down bolts tying roof to ualls. This too can only be

avoided by proper design and detailing.

8.2.3 liialls

Lightweight e.g. wooden walle, occasionally suffer

uplift and this is usually due also to lack of straps

tying walls to foundations.

8.2.4 Glazing

Failure of windows and glazing during extreme winds

often create adverse conditions for uplift on roof

structures and increase wind forces above those allowed

for in design. Such apparently minor details as glazing

and window anchorages should be properly designed.

9.0 LOlii-COST BUILDING DESIGN PROBLEWS UNIQUE TO JAHAICA

The following is in certain respects a summary of

the problems mentioned in this report and in Appendix I.

9.1 Building Codas and Standards

As agreed in the hlorkshop Conference on "Development

of Design Criteria and Methodology for Low-Risa/Low-Cost

Buildings to Better Resist Extreme Uinds", held in nanila,

there is a great need for simple instructions set out

in a "nanual of Accepted Practice" for the guidance of

engineers, architects, developers, etc. This would be

supplementary to Building Codes and would provide guidance

on simple low-cost houses, that could be understood by

even the untrained builder.
34 -

LOy-COST BUILDING DESIGN PROBLEHS UNIQUE TO 3AWAICA CONTD,

Building Codes and Standarda contd.

liihere there ie not yet a Registration LaWf this

need is even more urgent, as buildings are often designed

and constructed by persons without professional training.

Structural Problem Areas

For the currently popular structural systems in lowcost housing, i.e. hollow concrete block walls and metal

sheet roofing on timber rafters, the major problem area

is roof fastenings and holding down provisions. General

practice for holding down provisions at present, is

nominal and not covered by codes. Accurate data on design forces, or recommended standard details as mentioned above, would ensure both economy and a consistent and adequate standard of safety.

CONCLUSION

The foregoing is an attempt to give a description

cf low-cost housing and extreme-wind-related problems in

Jamaica and some parts of the Northern Caribbean.

The objective of this report and its Appendix I is to provide information on other developing regions

within the Northern Caribbean Area. Information from

this report will enable the final analysis and racommenda-^

tions from the project to be of mora universal applicability^
- 35 -

LIST OF REFERENCES <

1. Kingston and St. Andrew Corporation

Draft Building Regulations - 1971

Part 2 - Structural Requirements.

2. Wind Loads for Structural Design

Draft Code of Practice - August 1970

by Barbados Association of Professional Engineers.

3. Plinimum Requirements for Thin Section Precast Concrete

Construction ( ACl-525-63 )

.

4. British Standard Code of Practice No. 116 - 1965

The Structural Use of Precast Concrete.

5. Economic Survey, Jamaica - 1971 and 1972.

6. "The Return of Timber" by N. A. Goldeon and

"Uood Preservation - the liiolmanising Process" by D. Henderson

from - The Daster-builder Uol. 7; No. 2; 1968 (Jamaica)

7. "Esso turns Sugar Cane lilaste into Particle Board"

Daster-builder V/ol. 7; No. 3.

8. "Thermo lilall Systems" by Abe Caleb

Plaster-builder Vol. 7; No. 2; 1968.

9. "Breakthrough in Housing: Prospect seen for $13Gri annually

from Bagasse" - Public Opinion February 23, 1973 ( Jamaica)

10. "Daily Gleaner (Hurricane Special" August 19, 1951

Jamaica.

11. "Cross Section of Jamaican Housing"

The Jamaica Daily News, Real Estate Section, November 4^

1973; Page 6.

12. "Industrialisation the only Possibility - A House Progrft^mro^

for a Developing Country" by J. Bietry

The naster-builder No. 3; 1967 (Jamaica); Page 6.

13. A National Physical Plan for Jamaica 1970 - 1990. October

1971.

United Nations Special Project "Assistance in Physical

Development Planning",

14. Jamaica Architect, Issue 8; 1971 - "Housing".
- 36

LIST OF REFERENCES CONTD.

15. "Genesis of a Jamaican Building System" by A. 3. Benghiat

The Plaster-builder, December 1966 and flay 1967 (Jamaica).

16. "Good Building Practice Prevents Hurricane Damage - A Report on the Effects of Hurricane "Betsy" on Nassau - 1965" by 3. PI. Wint

Scientific Research Council - SRC Technical Report 2;

- 1966 (3amaica)

.

17. "Hurricane Precautions for Tropical Buildings" by 3. PI. Uint,

Scientific Research Council (3amalca).

18. "Concrete Masonry Structures - Design and Construction",

3ournal of the American Concrete Institute, Play 1970 and

3une 1970.

19 "Low-cost Housing and Extreme liJind Related Problems in

3amaica", Report No. 1, November 1973 by A. D. Adams for

NBS/USAID.

20. 1973 Labour Agreement by the 3oint Industrial Council

for the Building and Construction Industry.

21 "Extreme yind Speeds in the Caribbean" by H. C. Shallard,

Pleteorological Caribbean Institute.

The 3ournal of the Barbados Association of Professional

Engineers, December 1972.

22. "Zinc and Trees - Watch these for next Hurricane" by

Nellie Olson, Daily Gleaner, August 31, 1951.

23. National Atlas of 3amaica, November 1971

United Nations Special Fund Project "Assistance in

Physical Development Planning",

> ... Town Planning Department, Kingston, 3amaica.

24. Records of the 3amaica Pleteorological Office.

25. Interviews with PIr. C. 3. Evans, Deputy Director,

3amaica Pleteorological Office.

26. "Population Trends and Housing Needs", Department of

Statistics, 3amaica.

27. "Population Cancus 1970 - Dwellings", DSpartment of

Statistics, Kingston, 3amaica.
37

LIST or REFERENCES CONTD.

28. "How the Site and Service Program will Work" by Clive Bryan

The Jamaica Daily News, Real Estate Section; Flay 19, 1974.

29. Economic and Social Survey, Damaica; 1973 by National

Planning Agency.

»**«*•**«««*«*«•»**•**«««»«*«***
I
APPENDIX I

******«*«**«««***«

LOW-COST HOUSING AND EXTREME WIND-RELATED

PROBLEMS IN JAMAICA

REPORT NO. 1

For

NATIONAL BUREAU OF STANDARDS

and

UNITED STATES AGENCY FOR INTERNATIONAL DEVELOPMENT

•INVESTIGATION OF WIND RESISTANCE OF

LOW-COST HOUSES'

By A. D. Adains

Consulting Engineer

Jamaica

November, 1973

- 1 - CONTENTS

SECTION ITEM

CONTENTS

LIST OF ILLUSTRATIONS

SCOPE

LIMITATIONS AND ASSUMPTIONS

General

Data Gaps in Design and

Construction

Socio-Economic Considerations

COMMON LOW-COST HOUSING SYSTEMS IN

JAMAICA

A Look at the Past

Hollow-Concrete Masonry Construction

Large Panel Precast Concrete Systems

Small Unit Precast Concrete Systems

Timber Systems

Other Lightweight Systems

Other Low-Rise Buildings

PROBLEMS AND DATA GAPS IN DESIGN AND

CONSTRUCTION OP LOW-COST HOUSING

Local Building Regulations

Structural Systems

Hollow-Concrete Block Masonry

Large Panel Precast Concrete Systems

Small Unit Precast Systems

Timber Systems

Other Lightweight Systems

.General Comments on Lightweight

Roofing

SOCIO-ECONOMIC CONSIDERATIONS IN

DESIGN

Definition of Low-Cost Housing

Corresponding Income Group for LowCost Housing

Annual Figures for Construction of

Low-Cost Units

House-Purchaser Preferences in

Construction Materials

PAGE NO .

1

5

'

4

4

4

5

5

5

9

10

12

13

14

14

14

14

16

16

17

17

18

18

19

20

20

20

20

22
- 2 - CONTENTS

SECTION ITEM PAGE NO .

6 . DISCUSSION OF EXTREME-WINDRELATED PROBLEMS 22

General 22

Summary 2 3

7 ' LIST OF REFERENCES 24

/
- 3 -

LIST OF ILLUSTRATIONS

FIGURE NO . DESCRIPTION PAGE NO .

Fig. 1 "Wattle and Daub" 6

Early low-cost housing construction

in Jamaica

Fig. 2 . "Timber Stud and Boarding" 7

Early low-cost housing construction

in Jamaica

Fig. 3 "Brick Nog and Concrete Nog" 8

Early low-cost housing construction

in Jamaica

Fig. 4 "Hollow Concrete Masonry 9

Construction"

" The most common construction

method in Jamaica"

Fig. 5 "Large Panel Precast Concrete System" 11

"The most established, fully prefabricated housing system in Jamaica"

Fig. 6 "Small Unit Precast Concrete System" 12

Fig. 7 "Timber System" 13

Stud and lap boarded walls
- 4

-

LOW-COST HOUSING AITD EXTREME-VIND-RELATED PROBLEMS

IN JAMAICA

by A. D. Adams

Consulting Engineer, Jamaica

1* SCOPE

This report presents an outline of low-cost housing

and low-rise building- related problems of Jamaica and

data gaps both in the design (e.g. structural systems,

connection details, design loads, etc.) and construction

phases. It identifies the related socio-economic considerations as they affect the design of structures. It

presents also, a discussion of extreme-wind-related problems as found in Jamaica.

Due to the shortage of time mentioned, the practice

and problems mentioned in this paper are based on .Jamaica

only and does not include other Northern Caribbean Islands

2. V LIMITATIONS AND ASSUMPTIONS

General

This is the first of two reports. It is intended to

present infomnation of a more general nature here and to

present more detailed information and substantiating data

in the second report. This is partly necessary because

of the short time that was available for developing this

report.

In addition, there is a lack of technical reports on

the effects of past occurrences of extreme wind in

Jamaica. For aspects connected with the observed effects

of extreme wind, some reliance has had to be placed on

newspaper reports and photographs and other records and

papers. Not all of these sources are engineering-oriented

hence they have been interpreted with some caution.
- 5 -

LIMITATIONS AND ASSUMPTIONS CONTD.

Data Gaps in Design and Construction

For identifying data gaps in design and construction,

the author has mainly drawn on his own experience as a consulting engineer and his association with other

engineers in Jamaica. This means that data gaps are

indicated where information may conceivably exist, but

is not known by or readily available to, the majority

of Jamaican engineers. The second report will, of

course, re-examine any statements made in the first,

Socio-Economic Considerations

For socio-economic considerations, statistics and

economic analysis are based on government reports tinless

stated otherwise.

Observations on social and sociological aspects are

often subjective but where supported by other reports or

studies, this is noted by reference to the sources,

3. COMMON LOV-COST HOUSING SYSTEMS IN JAMAICA

A Look at the Past

An examination of common housing systems in Jamaica

should perhaps be preceded by a historical look at 'lowcost' housing as it existed before the advent of modem

industrialised buildings and building materials. This

seems even more relevant when it is considered that at

the time of the last severe hurricane in 1951 i most houses

were of 'early' construction as described below:

In the rural areas, most 'early low-cost' houses

(say up to the 1930' s) were constructed by peasant

owners, using techniques described as "wattle and

daub" (See Pig, l). This consisted of a wooden

skeleton frame of posts planted in the ground, tied

at eaves level with wooden beams and with sticks

interwoven horizontally between the posts, to form

the "wattle". This "wattle" was 'daubed" both inside

and out with mud formed from readily available clay,

to create solid walls. Roofs were of pitched wooden

framing and battens. The roof covering was generally

formed of 'thatch', made from bundles of dried leaves

of certain plants, tied in place.
- 6 -

COMMON LOW-COST HOUSING SYSTEMS IW JAMAICA CONTD.

A Look at the Past contd.

f

E^Kb-f LovA>/ <=.^>s,T WOU SIMS

i

4-

PART tU&VAsTIOKJ

Op WA^TTLt
- 7 -

COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA ^ONTD.

A Look at the Past contd.

6i,<=v<v «o«i> 3.

r n

-C O NO « EX i: «1Pr n

' V-v( C5 OOE-t Jo 1 ==.-T

EAR.Lv Low COST H<=>U6»IMG

In urban areas, houses were mainly of timber studs

with lapped horizontal boarding to walls (See Fig. 2).

Roofing was of pitched timber rafters with corrugated

iron sheets or wooden shingles, either on battens with

a thin suspended ceiling, or on board-sheathing without a ceiling.
- 8 -

COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA CONTD.

A Look at the Past contd.

, WOCiCjEhj

«=>r Eaglet >^ MOG,

As a variation in some cases and also as a further

development as time passed, many houses in the urban

areas came to be built of brick-nog or concrete-nog

construction (See Fig. 5). This consisted of masonry

or concrete in-fill between the studs and a rendering

of lime or cement plaster. A feature of both types was that in most cases houses were elevated at least

2 or 3 ft. above ground on concrete or masonry piers

or 'sleeper' walls.
- 9 -

COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA CONTD.

Hollow-Concrete Masonry Construction

M ^ fi, Ki It s^'

4

HOLLOW OQ>>i<l.egTfc MA>c^«PKH^Y.

0<i:»4e»-rf^UcT>0>0 . f»0 ue.6.b &-TlfPK*4«tE.

t=&Mfc^T Moie.-rA.ia.
- 10 -

COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA CONTD.

Hollow-Concrete Masonry Construction (See Fig. 4)

The introduction of the hollow-concrete block as a cheap masonry Tonit for walls, marked the development of

the first major constiruction method using locally manufactured components as a basic building material for

low-cost houses.

Selected vertical cavities in concrete blocks are usually filled with concrete during construction and

vertical and horizontal steel bars are introduced as reinforcement to resist earthquake and wind effects.

Poured-in-place reinforced concrete stiffener-columns

are generally introduced in xmrestrained panels of wall

exceeding about 16 ft. However, for low-cost housing,

these stiffeners are often omitted and both cavity infill and reinforcement are generally restricted to

comers and edges of openings. Reinforced concrete

belt beams are used to cap walls at roof level.

Roofing Systems are of various types and include

poured-in-place reinforced concrete slabs, and battens

on timber joists covered with aluminium sheeting or wooden shingles. Foundations are of strip-footing type.

Large Panel Precast Concrete Systems (See Fig. 5)

These consist of full size concrete wall panels, with

the largest panels being as large as the full length of

the housing unit in one direction and the full storey

height in the other.

In the most common local system of this type, wall

and roof-panels are lifted and assembled by crane and

connected by welding at matching steel inserts. Overall thicknesses of wall units vary from 3" to 6" but

ribbed panels are often used for the thicker units with

rectangular panel thicknesses of as little as 1^" between

ribs

.

Roof waterproofing is usually of a bituminous com- pound or waterproofing felt.
- 11 -

COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA CUNTD.

~rWE MOST e."^"T.*>Ne>V.»S,HeO ^ PUUU^ R«.E:.FAveaKlc:-/!><TEC>
COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA CONTD.

Small Unit Precast Concrete Systems (See Fig, 6)

These consist mainly of precast concrete posts and

precast concrete or timber beams with concrete in-fill

"boards" between posts.

Roofs are generally of timber framing with aluirinium

sheeting. In some cases, precast concrete joists end

"boarding" are utilised with felt waterproofing.
- 13 -

COMMON LOW-COST HOUSING SYSTEMS IN JAMAICA CONTD.

Timber Systems (See Fig. 7)

These are mainly of timber studs and 1" thick horizontal

boarding on both internal and external wall surfaces. Roofs

are generally of tiiiiber framing and aluminium sheeting.

These houses are usually elevated on piers or sleeper walls at least 2 ft. to 3 ft. above ground and

provided with a flooring of timber joists and boarding.
- 14 -

COMMON LOV-COST HOUSING SYSTEMS IN JAMAICA CONTD.

Other Lightweight Systems

Apart from timber boarded systems, other lightweight

systems have been proposed and promoted, particularly by

commercial or manufacturing interests. These types

generally utilise a stud system either of timber or

aluminium. Some of the boarding materials proposed so far are:-

(a) Particle board consisting of cane fibre

(bagasse) bonded by a resin.

(b) Therao-wall panels consisting of bagasse

and gypsum bonded by a resin.

However, to date, very little if any houses and certainly

no large scale developments have been done using such

lightweight systems.

Other Low-Rise Buildings

For buildings under 5 storeys and requiring substantial external walls or .partitions , filled hollow-concrete

masonry is the most popular construction method in Jamaica.

This is usually in conjunction with poured-in-place reinforced concrete floor slabs. Roofs are either R.C. slab

or timber framing with aluminium sheeting.

For office and commercial buildings and for low-rise

buildings above 3 storeys, the most popular construction

system is cast-in-place reinforced concrete slabs and

frames. Less popular variations are for slabs, composite

pretensioned/reinforced concrete or post-tensioned slabs,

and for frames, steel skeleton or R.C, shear wall

construction.

PROBLEMS AND DATA GAPS IN DESIGN AND CONSTRUCTION OF

LOW-COST HOUSING

L ocal Building Regulations

Most of the building regulations now legally in force

in Jamaica, were first passed in the early 1900's. Despite

a number of amendments of individual sections, the official

building laws are out of date and far behind modem building design and construction technology.
- 15 -

PROBLEMS AND DATA GAPS IN DESIGN AND CONSTRUCTION OF

LOW-COST HOUSING CONTD.

Local Building Rei^ulations contd.

There has been a tacit acknowledgment of this by most,

local authorities and today a lot more observance is made

of a Proposed Draft Building Regulations - 1971 than of

the original regulations. These Draft Regulations issued

by the Kingston and St. Andrew Corporation (which

administers the affairs of the Capital City) is not yet

available to the general public, but is well known to the

initiated such as Engineers, Architects and Builders.

These regulations have been mainly based on the series

of British Standards and British Standard Codes of Practice

dealing with the design and construction of buildings.

This is due to the fact that, so far, Jamaica has not had

the financial or man-pov/er resources, which would be needed

to undertake the intensive study and research necessary to

produce a comprehensive set of truly indigenous codes of

practice.

One consequence of this has been a lack of detailed

guidance in regulations on special local phenomena, such

as earthquakes and extreme winds. There is, therefore, a lack of uniformity in the treatment of these design problems

by Jamaican Engineers. The most popular recourse has been

to turn to areas such as the United States with its areas

of similar naturally occurring phenomena e.g. to the

Structural Engineers Association of California for earthquake design.

An encouraging development in this area, has been the

efforts of the Engineering Institutions in the Commonwealth

Caribbean Area (CEO) to co-operate in developing individually, separate sections of a comprehensive building code,

which would eventually be compiled to serve the entire

Commonwealth Caribbean region.

One such effort by the Barbados Association of

Professional Engineers, has produced "Wind Loads for

Structural Design" Draft Code of Practice - August 1970.

This too, was largely modelled on a British Code of

Practice BSCP3 Chapter V: Part 2: 1970: Wind Loads, with

respect to design life of buildings, topography, ground

roughness, building size and height above ground. However,

most importantly, it proposed basic wind speeds for various

islands in the region, based on analysis of local wind data.
- 16 -

PROBLEMS AITD DATA GAPS IN DESIGN AND CONSTRUCTION OF

LOW-COST HOUSING CONTD.

Local Building Regulations contd.

Local examination of this code has raised one or two - unresolved points; namely, the size of hurricane gusts

for the proposed averaging times and modifications to wind

speed factors which allow for variations in return period.

Nevertheless, although the document is not yet widely used

by practising engineers in Jamaica, it should represent

the most reliable guidance on basic wind speeds in the

region for design purposes.

Structural Systems

Difficulties common to all construction methods will be

dealt with further in this report but problems and data gaps

associated with various structural systems are best discussed

under their individual headings

.

Hollow-Concrete Block Masonry

For the more usual single-storey buildings involved in

low-cost housing construction, load stresses are usually

quite low, so that the tendency has been to design in

accordance with certain nominal rules set down in regulations to ensure minimiim standards. The provision of rein-

'forcement, belt beams, poured stiffener columns and the

filling of selected block cavities to improve earthquake

performance, goes even further towards increasing factors

of safety under wind and vertical loads.

For low-rise buildings with more highly stressed wall

elements, local regulations provide little guidance for a rational working stress design except to state in the draft

regulations^ that "allowable working compressive stresses

in masonry walls shall not exceed ----- 100 lb, per sq. in.

gross area in the case of hollow concrete blocks" and to

specify a minimum crushing strength on gross area at 28

days, of 750 lb. per sq. in. For such buildings, therefore,

the practice has been to design in accordance with foreign

standards such as the American Concrete Institute Report of

Committee No. 531 or British Standard Code of Practice

No. III. These standards are, of course, not applicable in

every respect to entrenched local practice. As a result,

the local Institution of Engineers is at present engaged in

preparing recommendations for the design and construction

of this type of building.
- 17 -

PROBLEMS AND DATA GAPS IN DESIGN ASD CONSTRUCTION OF

LOW-COST HOUSING CONTD.

Hollov-Concrete Block Masonry contd.

One area of uncertainty, unresolved to date, is the

necessity for a maximum spacing of poured- in-place R, C.

stiffener columns and their effects in enhancing the

strength of the masonry walls under vertical loads or

wind and earthquake loads.

Large Panel Precast Concrete Systems

3 4 Although there are foreign standards and design codes

which give general guidance on precast concrete work, there

are no comprehensive codes which cover the various types

and combinations of precast assembly systems and connections.

However, these systems are generally mass produced and are

usually manufactured by large, highly organised building

concerns. For this reason, they are also usually designed

and supervised by qualified engineers and architects.

Nevertheless, there is a great need to develop standards

for the use of local authorities and design engineers.

Among the specific items which can be solved only by

individual engineering judgment at present are:- .

(a) The design of welded metal connections with

bar anchorages to achieve ductility;

(b) Joint waterproofing and the avoidance of rain

penetration in 'flat' thin section, precast

concrete roofs;

(c) The design of welded metal connections with

bar anchorages, subjected to combined shear

and tension forces.

Small Unit Precast Systems

These fall in a somewhat different category from the

large panel systems. Although mass production is usually

necessary for economic reasons, in this case erection does

not demand large lifting equipment.

This lends itself well to the erection of small niimbers

of houses in scattered locations. The Jamaican Ministry of

Housing in its "Owner Occupier Scheme" has been erecting

a few hundred of these annually for the last ten years.
- 18 -

PROBLEMS AND DATA GAPS IN DESIGN MD CONSTRUCTION OF

LQV-COST HOUSING CONTD.

Small Unit Precast Systems contd.

The main problem with such units is the design of

robust joints for members of such small dimensions

»

Where all members are precast, connections between posts

and beams are generally made by half-lapped and dowelled

joints. Boarding is usually slotted into place along

vertical grooves in posts. This would generally provide

doubtful overall lateral stability under wind or earthquake shears, so that great reliajace has to be placed on

the embedment of the posts in deep concrete footings.

Where timber beams are provided with concrete posts,

connection is provided by bolted U-shaped mild steel

straps

.

Timber Systems

Local draft regulations provide for the design of

timber buildings using some cross-referencing to British

Standard Code of Practice No. 112.

Formerly, the problem with timber was poor durability

due to rot and decay in our sub-tropical conditions. This

problem has been largely solved by the use of modem

pressure-applied preservatives".

Recognised local practice is to provide straps at roof

and floor levels to resist the uplifting effects of extreme

wind, but this is not explicitly mentioned in the local

draft regulations.

Other Lightweight Systems

As mentioned before, there have been too few examples of

the use of resin bonded cane (or wood) fibre for external

work to provide an assessment. The patent-holders and

manufacturers claim the following attributes s-

(1) Dense surfaces

(2) Termite and rot resistance

(3) High Water repellence

(4) High screw and nail holding properties.
- 19 -

PROBLEMS AND DATA GAPS IN DESIGN AND CONSTRUCTION OF

LOW COST HOUSING CONTD.

Other Lightweight Systems contd.

In the constant search for very cheap housing systems,

these materials -represent attractive possibilities because

of their lightness and consequent cheaper construction

cost. However, the local government authorities and

engineers in general, are still uncertain of the durability,

strength, stiffness, weather-resistance and fire-resistance

of these materials. Data on the performance and capabilities of these materials is limited and very restricted m

circulation. They consist mainly of laboratory tests commissioned by the manufacturers themselves. As would be

expected, there is no mention of these materials in the

available codes of practice or regulations for the design

of buildings. In the present situation, there is a natural

reluctance on the part of our understandably conservative

government authorities, to approve such designs, even where

submissions are made by qualified engineers.

General Comments on Lightweight Roofing

The greatest single problem in the wind resistance of

buildings in Jamaica is in connection with lightweight

roofs. This was very evident from newspaper reportsl^ of

damage resulting from the last severe hurricane in August,

1951. The damage usually falls into two categories :-

(a) Stripping of roofs due to inadequate fixings

to roof coverings (particularly of metal

sheeted type)

(b) The lifting and removal or destruction of

complete roof assemblies due to inadequate

holding-down force at tops of walls.

Since the 1951 event, general building practice has

been improved e.g. to provide fasteners with large heads

and/or washers and to provide mild steel "hurricane straps"

tying rafters to walls.

Design codes and local regulations give no explicit

instructions for these provisions so that design is not

done on a rational basis except where an engineer is

engaged. At present the majority of houses (excepting

large housing schemes) are done without the use of engineers

so that such provisions are detailed nominally.
- 20 -

SOCIO-ECONOMIC CONSIDERATIONS IN DESIGN

Definition of Low-Cost Housing

The classification "low-cost housing" refers to different

cost categories in different countries. Furthermore, in

each particular coxintry, the cost category can vary drastically with time as inflation pushes up the cost of construction.

The current definition of "low-income" housing in Jamaica,

including land, on a developed site, is a house, the cost of

which must be under JS5,000 (US$5 , 500)^1 . This implies a

construction cost by the author's estimate of J$2,300

(US$2,530). Virtually all hous ing being built by the private sector today can be said to fall outside of thie category. Up to the present time, therefore, low-cost housing

can be described as government -built or government-financed

housing.

Corresponding space "requirements of 350 - 450 square

feet have been quoted for "proper minimiim standard, small

housing units" as an international standard for minimum

social housing in developing countries. However, this is

not envisaged as an attainable standard for people with no

fixed income and here in Jamaica, such houses reach a minimum of 200 square feet.

It should be noted that for the smaller houses, space

and provision are almost invariably made for future extension by the owner.

Corresponding Income Group for Low-Cost Housing

This is, of course, determined by the ability to make

down-payments and mortgage repayments for privatelyfinanced houses (usually 20 year mortgage). Even amongst

the least costly estates built by private enterprise, the

down-payments effectively eliminate those earning much

less than J$30 (US$33) per week or J$l,560 (US$1,723) yearly.

Government -hous ing, however, is within the financial capabilities of persons with two-thirds that income in the

urban areas and in some types of schemes even less in

rural areasl5.

Annual Figures for Construction of Low-Cost Units

The following are some figures for low-cost housing

units completed by the Ministry of Housing5 or under

Government Mortgage Insurance Scheme:
- 21 -

SOCIO-ECONOMIC CONSIDERATIONS IN DESIGN CONTD.

Annual Figures for Construction of Low-Cost Units

Table 1

SCHEME

STRUCTURAL

CATEGORY

NO. OF UNITS COMPLETED UNDER

CONSTRUCTION

AT 3IST DEC.

,

1970 1971 1972 1972

Government

Housing

Scheme

HollowConcrete

Block

Masonry

463 455 422 836

Slum

Clearance

and

Rehousing

- do - 63 22 570

Owner/

Occupier

Small

Section

Precast

Cone Units

454 380 253 37

Farm

Housing

- do - 287 91 _

Indigent

Housing

Timber 26 187 354 94

'"Mortgage

Insurance

Scheme

( Inspection only)

Large

Panel

Precast

Concrete

Figs . not

available

427 378 Figures

not

available

* Approximately 700 houses annually in this category have been

built by the private sector during the last 10 years. However,

few of these could be defined as 'low-cost' 5

> 13
- 22 -

SOCIO-ECONOMIC CONSIDERATIONS IN DESIGN CONTD.

House-Purchaser Preferences in Construction Materials

There is a well established preference in Jamaica for

concrete houses^J. There is a considerable consumer resistance, for instance, against the purchase of houses made

of lightweight material unless financial restrictions make

this unavoidable.

A similar prejudice exist against precast concrete

houses (especially those of thin section) but to a far

lesser extent and this prejudice is rapidly disappearing.

Hollow concrete block masonry remains the most popular

material for all income groups.

DISCUSSION OF EXTREME -WIND-RE LATED PROBLEMS

General

Jamaica enjoys the unwelcome distinction of being in an

area of frequent hurricanes and also being in an active

earthquake belt. A more rational approach to design against

both phenomena has developed over the past 20 years; the

general conclusion has developed that where construction

is in concrete, provisions to create good earthquake resistance will tend to produce adequate wind-resistant buildings.

This is mainly for single storey residential construction, where it is assumed that stability against overturning

will hardly be a problem, but that instead, the main concern

is local suctions and pressures. This is mainly true where

both walls and roofs are in concrete, but is certainly not

true of the very popular lightweight roofing used in such

construction.

In the case of total Ughtweight construction, such as timber, wind is, of course, critical and Jamaica has

experienced wide-spread damage in the past when this was

not fully recognised. Where adequate fastenings and holdingdown devices have been provided, buildings have performed

well both here and in other adjoining islands ' '.

Another minimising factor in the effect of hurricanes

on Jamaica, is an effective hurricane tracking and warning

service, administered by the Meteorological Office, Jamaica.

In the hurricane season, the public is constantly reminded

of the necessary precautions and this minimises greatly the

effect of any hurricanes.
- ?3 -

DISCUSSION OF EXTREME WIND-RELATED PROBLEMS CONTD.

Summary

The following is a sununary of extreme-wind-related

problems which require attention or further examination:

(a) Wind Loads: Determination of goist sizes in

hurricanes

(b) Hollow-Concrete Block Masonry: Necessity for and

effects of poured stiffener columns

(c) Large Panel Precast Concrete Systems:

(i) The design of welded metal connections with

bar anchorages to achieve ductility.

(ii) Joint waterproofing and the avoidance of rain

penetration in flat thin-section, precast

concrete roofs.

(iii) The design of welded metal connections with

bar anchorages, subjected to combined shear

and tension forces.

(d) Timber Systems: Simple minimum requirements for

providing resistance against uplift,

(e) Other Lightweight Systems:

(i) Durability

(ii) Strength and stiffness

(iii) Weather Resistance

(iv) Fire Resistance

(f) Light Roofing Systems

(i) Effectiveness of fasteners in resisting uplift

forces on metal sheets.

(ii) Simple rules for minimum provision in preventing uplift of overall roof system.

A. D. Adams

November, 1973
- 24 -

LIST OF REFERENCES

1. Kingston and St. Andrew Corporation

Draft Building Regulations - 1971 » . Part 2 - Structural Requirements,

2. Wind Loads For Structural Design

Draft Code of Practice - August I97O

by Barbados Association of Professional Engineers.

I 5. Minimum Requirements For Thin Section Precast Concrete \ Construction (ACI-525-65).

4. British Standard Code of Practice No. II6 - I965 ; The Structural Use of Precast Concrete II 5. Economic Survey, Jamaica - 1971 and 1972

6. "The Return of Timber" by N. A. Goldson and

"Wood Preseirvation - the Wolmanising Process" by D. Henderson

from - The Master-builder Vol. 7? No. 2; 1968 (Jamaica)

7. "Esso turns Sugar Cane Waste into Particle Board"

Master-builder Vol. 7; No. 5.

8. "Thermo Wall Systems" by Abe Caleb

Master-builder Vol. 7; No. 2; I968.

9. "Breakthrough in Housing: Prospect seen for $150M annually

from bagasse" - Public Opinion February 23 > 1973 (Jamaica)

10. "Daily Gleaner (Hurricane Special)" August 19, 1951

Jamaica. IB

11. "Cross Section of Jamaican Housing"

The Jamaica Daily News, Real Estate Section, November 4» 1975

Page 6.

12. "Industrialisation the only Possibility - A House Programme

for a Developing Country" by J. Bietry,

The r.HSter-builder No. 3» 19^7 (Jamaica) Page 6 ^

15. A National Physical Plan for Jamaica 1970 - 1990. Octpber I97I

United Nations Special Fund Project "Assistance in Phy^bical

Development Planning".

14. Jamaica Architect, Issue 8; 1971 - "Housing"
- 25 -

LIST OF REFERENCES CONTD.

15. "Genesis of a Jamaican Building System" by A. J. Benghiat

The Master-builder, December I966 and May 196? (Jamaica).

16. "Good Building Practice Prevents Hurricane Damage - A

Report on the Effects of Hurricane "Betsy" on Nassau - 1965" by J. M. Wint.

Scientific Research Council - SRC Technical Report 2;

1966 (Jamaica).

17. 'Hurricane Precautions for Tropical Buildings" by J. M. Wint,

Scientific Research Council (Jamaica).

18. "Concrete Masonry Structures - Design and Construction",

Journal of the American Concrete Institute, May 1970 and

June 1970.

LOW-RISK LOW»Q0ST HOUSIWG AHP

gTRHig WIHP BKUTED PBOBUMS

Prepared Byj

Dr.Jamilur R» ChoMdhury

Associate Professor of Civil Eogineerinc

Bangladesh UniTersity of Engineering & Technology.

For

National Wntma of Standards

U.S. Departaent of 0»MMrea

W&ehlngton

LGir«HISS LOW<-COST HOUSING AIO) EXTHEMS WIND RELATED PROBLEMS IN B^NQLADSSH

Dv, Jamilur R. Choudhury

ABSTllACT

The report deals with the present housing conditions and extreme wind

related problems in Bangladesh. Bangladeshi with a population of about

75 million in an area of 55 i 130 square miles, has one of the largest

densities of population in the world* The housing conditions are one of

the poorest in the world. The problems are made all the mors acute due

to natural calamities - a third of the country is subject to nnnusl floods

and the coastal areas «re ravaged by periodic cyclones*

Most of the houses in rural areas are *kutcha* ('non-permanent*) struc*

tures, whose plinth is made of mud and whose walls and roofs art built of

bamboo, grass, straw and reeds* These houses often do not provide a safe

shelter against rain and storms* The stronger type of houses in rural areas

use corrugated galvanized iron sheets supported on bamboo or timber framing.

No special care is taken to anchor the roof to the walls or foundations*

According to the last housing census (I960), t .e aversige number of rooms

per household was 1*77 and a majority of households (53%) were single room

dwellings* It is estimated that the figures remain virtually the same today*

The conditions of urban houses are no better* The we|l<-to«do class live in

buildings with reinforced concrete flat roofs supported on brick masonry

walls. With increasing urbani^tion, squatter settlements are increasing

and most of these slum dwellers live in almost sub-human conditions*

Zxtreme winds occur in Bangladesh in three diffsrent forms i (i) the

Norwesters, (ii) Cyclonic storms and (iii) tornadoes* Norwesters are violent

thunderstorms occurring between March and May* They originate o%er land

and marshy areas and occur mostly in the central and eastern districts*

The distribution of Norwester squalls in the months of Marehi April, May

and June are shown in maps* The maximum wind velocities in Iforwssters ars

around 80 mph.

Cyclonic storms originating in the Bay of Ben^^ very oftsn hit ths coastal

aresLB of Bangladesh* They are most frequent in the Boath of Oetobsr* Usually
«2-

aeeoapaaiftd vitli etprm sargts« often 1^0 kO St* in doptht thoy oaum MrlOfM

daa&g* to haaan li7«o» oattloci houMo ud otlior proportits* Quo of tho •«Ttvt«t

eyeloaos dovaotatoA tho ooMtal arMfi of Baaglftdosh la Novoabori 1970* ViaA

•pooda upto 150 mifk lunro tooon roeordad ia roooat ojolaaoa* Ika C« Z« aliott

roofa of koaaaa ara maa^Ujr IAomb awBy« bat tlia daaago to briak aaaaavy walXa

aad R. C. roofa ia aot aavara*

Toraadooa« tho aoat doatruetlTo of all atoraa, ooeur in tho ooatral aad aaatpm

rogioaa* Tho oatakirta of Daeca elty voro davaatatod by a tornado la Aprilf

19^9* Tho wind apood oauaiag daaago uaa oatiaatod to bo in oseoas of I50 flflu

Hoat of the 'pomanoat* hmaaoa vith alopiag roofa naod to bo doaignod aaoardiaf

to a wln^ proasuro dorlTod froa tho foraola p » 0*003 whora p ia tha

proaaoro in Iba/aft and V ia tho doaign vind apaod ia aph* A eeanoa TaXaa af

V maod in doaigna ia 100 aph* Saation aad lift forooa voro ooaplotalj igaarad*

In rocont yeara, ®ithor tho B*3«Codo ao« 3 (Chapter V )| 1952 or tho A»S«CSS

recpaaendatione (1936) ia being naod« Thoae reeogniaa the offoot of alopa af

roof on the proasuro diatribution* Depending on the angle of inolinatioat

either auction or proasuro any be created on the vindvard aidoi whoroaa tha

leevard aide ia alwaya under suotion* Aero ia no Code of Building Praotiea

apeeifying the different deaign loada but after recent escporieaaea of ayaleaia

diaaatera, aoae deaigaera uaa an uplift proasuro of 25 lba/aq»ft« ia doaigaiag

the anchor eleaoata for roof atruoturea in lov«*riao builiinga.

«e«
Q9 T^Tll^m

f%g9 Ko.

1 INTBOnJCTIOF

1*1 General I 1.2 Population 1

1*3 EcoooMjr 2

2 THE HOUSING PBOBLBC

2*1 iDtroduetion 2

2*2 Rnral Hoosiiig 3

2. 2.1 Dwell lot Units 3

2* 2, 2 Straotmal Conditions of Sural Hoasoo 5

2.3 Urban Housing ^ 2*4 CoBBBOD types of houses 7

2«5 Some neir types of housee 8

2*6 Current Hons log FiogfMnee 9

3 SXTBBMI WIND BILATXD PVBLBIS

3.1 Types 11

3*2 The Norwtstete 18

3,3 Cyclonic Stone 13

3*3*1 Stem ttaoke and ffeqaenojr 13

3*3*8 Oisastyoas eyolonee of the pttst 15

3.3*3 Prohable Afeas of Atta^ 17

3*4 tornadoes 17

4. PRESENT DBSIGM CBITIRIA 18
I

1

i
1. INTBOOVCTION

1.1 GePTal

Bangladesh is odo of the youngest nations in the world.

Fonerly known as Bast Pakistan, it emerged as ao

independent nation after a short tat Yiolent war of

liberation lasting ahoat nine nenths frea Mareih I97I to

December 1971*

Geographically, it is located on the north-east of the

South Asian Sub-continent between 20^30* and a6®45*

North latitude and 88® and 92^56* Sast longitude. The

total area is 55*130 square miles, Alnost the whole of

the country is a network of rivers, constituting the delta

of three of the world's biggest rivers - the Brahaaputra,

the Ganges and the Mej^na*

The country is surrounded on the west, north and north-east

by India, on the south-east by Burva and on the south by

the Bay of Bengal.

1.2 Population

The present population is about 75 million. With an average

of about 1360 persons per square mile» Bangladesh has one

of the largest densities of population in the world. The

annual net rate of population increase in Bangladesh was

estiBiated to be 2.6 per cent in 1961. By the end of the

present decade the population is expected to be about

95 million.
* a •

ni ECOBOT

BangladMli is of th« poorest countries in the world.

The Gross Homos tlo Prodaet (constant factor cost at

1959/^ prices) was aljowt 4.57 billion dollars* in

FT 1970.

The ecoBoiiy of BanflAdesh is traditionally and predoainantly agrienltiiral. About 90% ot the popalation is raral

and about 8q% of these are eniagcd in afriealtore. Agrienltaral ontpat accoants for aboat 55J< of the CDF, The

per-capita real incoae is about 0 i4 (at the official

exchange rate), a figure which has renained alonst constant

since id.sizties* Total industrial output accounts for

OBljr 9% of the QH9 out of ivhich jute processing and Mnufaoture im the Mjor ooaponeat.

a« THS KOUSIHG FaOBLIM

a.i lp|ift4gffllfti

. The last housing census was oonduoted in 19^0. Arrange*

Bents for a population and housing census in Bangladesh

have been oeapleted and the census data collectioB should

be ceupleted bj the beginning of 1974* In the absence of

ap*to*date reliable data, aest of the following discussion

is based on the results of i960 census. The basic charmc*

teristies of house types, structural conditions, oeenpaacy,

etc* have not changed significantly during the last decade*

• The figntes quoted are unofficial estiaates.
In i960, th«re were al)oiit 9. 60 million residential

houses in Bangladesh, The average number of rooms per

household was 1.77« A majority of householdfx {33%) lived

in single- room dwellings and the average density of occupancy was 3.2 persons/room. Table I gives the number of

households classified according to nmber of rooms

t

Tayi? I Number of Houses of Different Sizes*

(Figures in thousands)

ITumber of

households

j>f all sizes

Number of rooms

1 2 3 4 5 6 7 8 9 10

9603 5166 2652 1063 443 161 65 as 13 6 7

Five or more persons share a rooa in case of 3t^ of the

popnl ration, 4 persons in case of 13/^ of the population and

. 3 persons in case of 21^ of the popalatlon.

The poor housing conditions of the general popnlace is

evident froa the above figures.

2,2 Rural Housing

The bulk of the rural population of about 67.5 million

belong to the poorest income group. Sine* the majority

of this population depend on agriculture as theix means

* Soureei Census of Pakistan, Vol.9, 19^
- 4 -

of llTellbood, the dlstrllntion of agricaltoral l»iid

holdinc has a aaikad affect on tha pattarn of raral

aco nbmfjnous/ioj .

Tha raral popvlation nay ha hroadly elasaifiad Into tao

groups} (a) land<»ownar0, and (h) landlaas lahoarars. It

is aa t&aated 1SbA\ ahont ona«rifth of tha illagars ara

laadlofls, who work aalnly as field hands or lahoarars ia

Tarioas projeots* Oat of tha gross araa of 55*130 sqaara

nilas^ahoat 25 ail lion aoras (70*R^ of the gross araa)

is ealtirahla. The araraga land owning Tillagar posseasas

only 1*5 aeras. Ha aaaally rants another acre froB wall*to*da

iI lagers and therefore oultiratas 2*5 acres. This area is

usoally frafseoted into ten or laore plots, so«e of which

say he a nile or no re wmy fros the hoBseatead* The hoasea,

in general tend to he scattered throughout the illage«

Most of the raral popalatioa in Bangladaah live on the

patriarchal fetaily pattera. Peasants usual ly estahlish

their hoaaeluilda on their own fields. When the sons get

arriedy their wiTes motc in with thaa» and a new heasa

(or reoa) is erected for thcB, on the saaa field, neit to

the parents* hoaae« 4s a oonseqacDca, houses occupied hy

fanilies paternally related are grouped together. The

clusters of hausas norMally proTida shelter to faniliee

of relatiTes motharing 20 • 40 menhers, hut hij^er fifaraa

are not iafraqaaiit. The groups of houaaa are usually
- 5 -

sarroanded by dense txoploal Tegetation and tfees, Fic.l

sbows the layout of a typical rural house* The central

courtyard is the centre of alnost all family aotlTltles.

2.2*1 Dw^lUPj Unn?

Most of the houses in rural areas are 'kutoha* (which

literally means raw) structure, whose plinth is made of

mud and whose walls and roofs are hnilt of henhoo, grass,

straw and reeds. These houses require constant nalntenance and often do not provide a safe shelter agaii^t

rain and stomi*

Accoiding to the last census report (19^0), there were

9.13 million residential dwelling houses In rural areas

of Bangladesh, The increase In nonher of rural houses

between I95O and I960 was about iO%, Assuming the same

rate of growth the number of houses In 1970 should have

been about 10 million.

2.2«2 Structural conditions of Rural Housee

According to i960 census data, about 90^ of the total

rural honses are made of bamboo, thatch and mad, and

^4»5% of the houses use the same material for roofs.

!l^l1s of concrete, baked bricks or stone are used In only

\% of the total number of houses* These are wstly the

staff quarters built by the goTernment* An average of

of the bouses hare C«I* (GalTanlzed oorra^ted iron)

sheets or corrugated asbestos cement sheets as reefing

materials*
The conditions of dvoUing units in mban ar«ae »ro no

better than those in the rarftl areas, A Tast Majority (72Jt)

of the urban population cannot afford to pay the rent for

even the cheapest forn of acceptable bousing* They haTe^

therefore, to liTe in Makeshift sha^s and hnts* These

distressing conditions trader whl^ the low income faailies

liTe present a problen which is seemingly beyond solvtien*

The total nniber of urban dwelling units, according to i960

census, was about 47tt000 and it is estiaated that there

were about 520,000 iknits in 1970. Approximately 27% of the

bouses are persuoient and seni-pernanent in charactert the

rest being te^wrary and unclassified. Quite a large frae*

tioo of the urban population live in the 'bustees' and

squatter settlemants in the larger towns and cities. They

liTe in banboo shades, often consisting of a piece of

plaited split*banboo fencing bent in the shape of a semi*

Circle* The headroom in such houses being low, their occu*

pants spend most of their time under ^he open sky, taking

shelter under the sha^s only in ease of rain and during

ni^t. The houses are blown away even by moderate winds,

despite efforts to held them down by putting counter*

weigihts like bricks on top of the roofs. The gcvernment

is making efforts te rehabilitate these squatters and has

already bet lit 4900 semi •permanent one- room bouses en the

outskirts of Bacea city.
- 7 -

2*4 CtommoD Types of Houses

A very common type of construction used for rural houses

is shown in Fig. 2. The roof consists of C«I«8heet8

screwed to tinher purlins, usually about 2" z 2" section*

The load bearing skeleton consists of bamboo posts* The

walls are of bamboo fencing consisting of split baaboo

woven diagonally, Galyanized steel wire is used in joining the different pieces. These houses are nerer designed

from the structural point of view, and are usually built

by local craftsmen, the owner sometimes providing unskilled

labour.

A stronger type of construction used for low*co8t housing

projects on the outskirts of Dacca by the Housing

Directorate of the Government uses brick walls with C,I*

sheet roofing (Fig. 3)* The C.I .sheet roof is anchored

down to the wall through l/8** x 1** x 5** twisted steel

clamps and 1/2** diameter 'holding down* bolts* These bolts

are about 2 ft. long with a 4" square l/B^ thick mild

steel plate welded at the bottom end embedded in the brick

masonry*<^

The stronger houses in urban areas are Mostly made of burnt

clay brlok masonry walls with sand ement mortar (usually

10** thick for buildings upto 2 stories high) with reinforced

concrete roofs. The roofs are almost invariably horlsontal^

* Sources Housing Directorate, Government of Bangladesh
. 8 .

In the dsslgn of such Ixiildiocs, qo aocoaot Is taken of

the wind forces* The walls heinn oHxeh thl^er than nece*

esary tiom srarlty load considerations, even extreme winds

do not prodaee stresses large enongh to produce fallare.

Most of the hnildings of this type which have suffered

danage due to cyclones were either nade of sub^standard

quality nortar or the worlcManshij) was poor. No damage to

B.C. roofs have been reported. In the island of Manpara,

one of the worst*affeoted areas of the NoTcnher 1970 cyclone

the only B.C. elwents which suffered damages were 'sunshades

which were about 2|" thiek, 1*-9'* projections above window

lerel. These failures might have been caused by uplift

wind pressure or the pressure generated by storm surges.

Some new types of houses

In recent years, efforts have been made by different relief

agencies as well as Government departments to evolve new

type of houses to better resist the natural calamities.

Some of these use tradiditional materials like CI, sheet

roofing whereas others are completely new in concept,

A very popular type of structure called GABX type bouses

(after the U.S. relief organisation Oo-operative for

Aateriean Belief Iverywhere) uses soil cement blocks for

walls and 0«I, sheets for roofs, Th9 primary emphasis is

on promoting housing on * self-help' basis, a minimom of

skilled labour being neeessasy for its cons truet ion,

Eowevert the problem of properly aaoboriog the 0,I,sheot
roofs to the wall still rwaalns.

HjrperliDlic paraboloid reioforc«d oonorot« sbolls roofs

baTo boon used in both Industrial boasiof and oabarban

boasinf. One systw uses 1** thick precast H,c. eleaents

with in-situ concrete interconnection* The roof is anchored

to the stipporting brick walls throng l/2** M.S. bars at

the corners, Cast-in*place hyperbolic paraboloid shell

roofs have also been used in a recently construeted industrial honsing project in Jessore*

GABE is experimenting with a revolutionary type of house

design. Both the shape and the materials used are eoaipletely new in Bangladesh. The integrated roof and wall

element is 8emi-«lliptic in shape and is made of pre*formed

elements of polyester resin, jute and polyarethane. These

elements are anchored to the underlying soil and their

performance in serore winds has so far been satiefaetory*

Qirrent Housing Prograies

Bangladesh had the misfortune of suffering two disastrous

natural calamities in 1970. In August 1970, flood waters

destroyed about 8o,000 rural houses completely} anreoTer

about 224t000 houses were partially damaged. In the severe

cyclonic storm of RoTemb«r 12, 1970 abovt 100,000 houses

were completely destroyed. The liberation ttmggle of I971

left about 2 million families homeloss. Attention of international reliof agencies and humanitarian or|aaisations
10 -

wer« natarally fooiisscd on Bangladesh after thpis series

of destraetions. Sizeable housinf rehabilitation and

reeons traction efforts are now underway in rvral areas*

The GoTeriBsent of Banfladesh through its Bural Rousing Befaabilitation ProJ set enrisafed the construction of 1 55,000

semi-pucoa rural houses and 21,000 pucca houses in the coastal

areas in 1972-73* The GoTernnent hM also undertaken construetion of 2-storied cyclone shelters in coastal areas which

will also serre as cooHunity centres, schools, dispensariee

and post-offices.

Table 2 shows the siiinry of housing progrunies undertaken

by the different relief agencies during the last two years

t

Table 2

Rousing Prograiane of different Belief

Organiaations in Bangladesh*

i ?^

I Target

Vas« of Organisation

Targei

upto

dbnstruetiea

upto

1. G4BX

3« OOlfCSRH

3. B,K«MissioB

4. BIRRS

5* OORR

12,500

2,000

1,500

45, 220

3 00,000

6. Uncle Crik*s Children Help 31

7. Serrice Civil International 925

8. SAWS 2,730

5.^

50

1,000

24,003

1 85.260

31

135

200
11 -

9. AUi»T£AJS 2,668 2,668

10. Baptist MlssloB 1i494 1.264

11. Danish Association for 125 ^5

International Oo«operation

12. EFIO0R 5S1 95

n. icac 991 991

I4.BSBS 15,060 2,960

15.SalTation Anqr 2,331 1>08l

16. IPS 1,000

17. BVSC 5.000

18. BRAC 1,000

Total 3 95.156 2 25,153

3. EXTREME WIIID RELATED PROBLBIS

3.1 Types

Eztrene vinds affecting houses in Bangladesh waj be classic

fied into three categories^

(a) The Nonresters" (iLaltaalshakis ' )

(b) Qyclooic Storas, and

(c) Tornadoes,

3.2 The yprwesters

Fonresters are Tiolent thander-storas and oecar daring

preaonsoon onths, i.e. March to Kay. They are aost

freqaent in the aentb of April (whi^ corresponds to

Baisbak, the first aonth of the Bengali calendar - hence

the naae 'Kalhaisbakl' )• Tbey originate oTex land and

• Sourcef Report on the Rational Woricshop on Low->oost and

Oo«operatiTe Bousing in Bangladesh, Hot. 29 - Dec 5,

1972, Prepared \ty International Gb-operatlTe oming Bvrelepaent Assoeiatloa.
« 12 .

narshy ar«M axxl oeear nwstly in tb« offistrsl and

eastern dlstsiete.

In a study of Horwester sqaalls ormt Dacca, It was olaeerred

that before the onset of a Nonrester, the prevailing

sarfaee wind was southerly or eeath-westerly hat wi^ the

onset of the squall, a sadden shift to the west, 8oath«>west

and even soath-east was ohserrede

Some of the Honresters originate from West Bengal and

Chotanagpor in India and move in a north-west to sooth-east

direction. Another category of Me rwesters originate frea

A»sa» In India to the north of Dacca and nove no re or less

in a southerly direction.

The area)- difitrlhatlon of Norwester sqoalls/ln the aonths

of March-Jane are shown in Figs* 4t 5* ^ 7«* It Is

observed that in the nonth of March, an area aroand Dacca

and north-east of Dacca has the highest concentration of

sqaalls* In the aonth of April, the March cell expands

in area and another cell near Sylhet near the north-eastern

boundary starts developing. In the mnth of May, three cells

are observedt

(a) the Dacca Cell well expanded,

(b) a cell near Faboa and aroand, possibly extending to

Caloatta 1b India} Mid

(c) Sylhet cell In the north-east becoalng prMilnent.

« Soareet The Cliaatology of Sast Pakistan by M.A.Qoadir,

Govt, of Bast Pakistan Pablieatlon, 1962.
- 13 -

In the month of June, only two cells are oteerved, hoth

with considerably reduced frequency distribution. These

are the decaying Dacca and Pabna cells.

The Maximum wind Telocities encountered in case of

Norwesters is in the region of 40 - ^0 miles per hour.

3»3 Cyclonic Storms

3.3.1 Storm tracks and frequency

The south-west mansoons, over which the entire agricultural prorluction of Bangladesh is dependent, is

ushered in pulsations, through the agencies of

'depressions' and cyclonic storms. High winds with frequent squalls, heavy rain and stona surgef are the

destructive agencies of a cyclonic storm.

A study of the storm tracks in the Bay of Benfal between

I89I-1923 reveals that the cyclones may originate anywhere

in the Bay of Bengal and then travel either North-west

towards the Madras coast in India or North and Northeasterly towards the head of the Bay. The Bay of Bengal

is practically free of cyclonic storms in the months of

January, February and March. In the months of April and

^fay, Bangladesh has occassional ly been struck by cyclones

affectihg the Cox's Bazar coast and the area East of

Barlsal. During the monsoon months of Jane, July and

August, cyclonic storms are freouent but of moderate

intensity and they do not affect Bangladesh; they totm

at the head of the Bay of Bengal and travel in West and
14

North-westerly direction to the Orissa and West Benga}

coa<8t in India. Cyclonic hazard is greatest in Bangladesh

in the period starting fron September and ending in

Decenber. Cyclones are then most frecinent and severe and

may attack any of the coastal areas at Madras and West

Ben^l in India, Bangladesh and Buma,

Table 3 eihoira the frepfuencies of cyclonic stoms and

depressions in the Bay of Bengal at different periods of

a year. Althoagh more depressions were formed in the months

of July, Aagast and September, the number of cyclonic storms

was much higher in the month of October.

Table y

Frequencies of Cyclonic Storms and

Depressions in the Bay of Bengal

jjqq^jj i depressions | Storms

I Total nosi I Total nosi

January 1 0

February 1 0

March 0 0

April 3 0

May 6 5

June 11

July 19 2

August 19 2

September 21 5

October \2 10

RoTMiber 2 5

DeceMber 3 2

• Sources Op. Git*
. 15 -

The total mimber of cyclonic storms by decades is glyen

in Table 4.

Table 4»

Total nurabei of cyclonic storms in

Bangladesh

(1890 - 1959)

1S90-1899 \ 68 of which 2 were reported devastating

1QOO-1909 I 65 II It 0

N II

1910-1919 I 48 H M

1 n n n

1920-1929 1i 77

tl It 3

tt H M

1930-1939 ! 81 H It 8

It n H

1940-1949 P 89 t« n 4

n n It

1950-1959 )r 76 H rt 0

II It N

3.3.2 Disastrous Cyclones of the Past

Coastal regions of Barisal and Noakhali districts have

been subject to severe cyclones and destructive storm

surges in the past. In such severe cyclones, thousands of

huTnan lives and cattle were lost» houses and crops worth

millionsof Takas were destroyed. Some of the more severe

cyclones of the past 4OO years are mentioned belowf

(a) Cyclone of 1'>84 ; The cyclone hit the districts of

Barisal and Fatuakhali, There was a hc(e storm surge

and nearly 200,000 people perished in the calamity.

* Source: Op. Cit.
16

(b) Cyclone of 1797 i The cyclODe affected the islands

south of Noakhali and has heen described as the

"iBost destTaotiTe**,

(c) Cyclone of t822t Unlike other cyclones, which generally

occur in October, a great cyclonic stonn ravaged the

southern areas of Bar i sal, Patuakhali and the islands

of Ratiya on June 6-8, l822. In the district of Barisal

alone about 72,000 people were killed.

(d) Cyclone of 1876 t The coastal districts of Barisal,

Patuakhali, Soakhali and Chittagong were hit by a

cyclone on October 31 - Not 1, 1876. Storm surge; upto

40 feet deep haye been reported from the coastal areas*

A total of 215(000 people were probably drowned. This

represented 20^ of the population of the affected

^ areas.

(e) Cyclones of 1Q60 t After a comparatiTely quiet period

in the first half of the century, two severe cyclones

hit the coastal regions of Barisal, Noakhali and

Chittagong in October 1960. The cyclones occurred in

' quick succession « the first one on October 9-10 and

the second on October The areas affected by

both the cyclones were almost the same in both the

cyclones.

A MZiMm wind speed of about 140 mph was reported

from Chittagong port.
- 17 -

(f ) Cyclone of 1Q70 i The cyclone of t2th NoTeinber 1970

is the most disastrous in recent times. It affected

the southern regions of Barisal, Patuakhall, Noakhall

and the islainds of Hatiya and Maopura, The accorapanying

storm surges were apto about 2^ feet in height. Almost

100^ of the kutcha and s^i»periiianent houses were

destroyed in the affected areas. The extant of damage

indicates that the maximum wind speed was more than

120 raph,

3»3«3 Probable Areas of Attack hy Cyclopic Storms in Bangladesh

The coastal areas of Bangladesh are the most vulnerable

to cyclonic storms originating in the Bay of Betigal. The

southein parts of Bar 1 sal ^ Patuakhali, Noakhali and

Khnlna districts and the western coast of Chittagong have

suffered extensive damages in recent cyclones. The severest

damage is caused in the off>shore islands of Hatiya^

Sandwip and Manpura, which are often completely inundated

by storm surges accompanying the cyclones. Afeas of Dacca

and Corailla districts are also affected but the intensity

Is less severe than in the southern regions*

Fig. 8 shows the probable storm tracks in different parts

of the year and Fig. 9 shows the track of a typical

cyclonic storm with maximum wind velocities in diffsresit

regions,

3.4 ToFPft^ft?

Tornadoes are the most destructive of all storms. They
- 18 .

generally occar on land during the warm season of the year

in flat areas, where there are few topographical barriers

to impede their movenent. The approaching stom may be

recognized by a dark funnel-shaped cloud whose small portion

extends downwards to the earth's surface. Usually such

stoms coyer a narrow path of upto about half a mile in

width and their force is spmit in 20 to 100 miles of travel*

The ma;}or flow of the air in motion at ground level during

a tornado is basically circular and translational at the

same time. The average translation speed is about ^0 mph

but the peripheral wind velocities are much higher. In

1961, the Task Committee on Wind Forces of the American

Society of Civil Engineers concluded that the peripheral

velocities would be in excess of 300 mph. However, maxiBun

wind speeds upto about 500 mph have been estimated by some

authors.

One of the severest tornadoes in recent momery hit the

outskirts of Dacca city in April 1969. A textile mill at

Demra, about 10 miles from Oacca, built of brick masonry

walls with C.I .sheet roofing on steel trusses was completely

destroyed. It is estimated that the maximum wind speed in

the tornado was in excess of I50 mph.

4« PBSSETfT OESIGN CRITERIA

Most of the existing houses in Bangladesh have never been

designed from a structural point of view» but their form and
- 19 -

use of various materials have evolved over decades of

experience and tradition.

For permanent and semi -permanent structure^, a very popalar

form of construction uses steel trusses or timber trusses

as the load carrying element of the roof. Corrugated galvanized iron sheets are commonly used as covering although

in some cases corrugated ashestos cement sheets are used,

Thf? trusses are designed to withstand wind forces which were

usually calculated in the following way:

If V is the speed of wind in sn^' ich the 'Structure

is to be designed, the pressure p in lbs/ft^ is taken to

p .0.003 V2

Ducherai^n's fonnula for sloping roofs was then used to

calculate the component of wind force normal to roof surface

torn p. ^ . , where 0 is the angle of

1 - Sin-^ 0

inclination of the roof with the horizontal.

Use of the above formula implies that wind forces act only

on the wind^ward slope of a roof and ignores the effect

of suction in the leeward slope.

However, most of the structures riesigned to withstand wind

forces calculated from the above formula with a wind speed

of 100 - 120 mph have withstood the forces generated by
20 .

severe cyclones. It Is worth noting that no account is

taken of Tertieal aplift forces which may be generated

by the cyclone.

Current design practicoy boweyer, uses a more realistic

pressure distribution. In the absence ofaunified code of

building practice in Bangladesh, most of the 'permanent'

buildings are designed either according to the British

Standards Code of Practice No. 3 (Chapter V) I952 or according

to American Society of Civil Ingineers report on Wind

Loading 09*5^)»

The B.S. Code recognises the influence of roof slope as

well as the height to width ratio of the building and the

reconmiendations are based on results of wind tunnel tests

on scale models carried out at the National Physical

Laboratory.

The A.S.C.C. reoonmendatione give wind pressures for a given

wind velocity with the angle of inclination of the roof

as the only variable.

The velocity pressure is taken as q • O.OO2558 v2 wher*

q is in lbs. /sq.ft. and V is in mph,

Th^JLe^jyard slope assumed to ^be subject to a suction of

0.6 q for all slopej whereas the windwMd slope pressure

(or suction forces) are given by the following ezpressionst
- 21 -

0.7q

(0.07 0 - 2.10)q

(0.03 0 ' 0.90)q

0.90q

(Positive values of p mean pressure and negative

values mean suction)

The above pressures anc? suction forces are assumed to

act In a direction perpendicular to the surfaces on which

they act.

The Internal pressures developed in buildings with openings

are not usually considered in the design of such structures.

/'s The nost cojTnonly used slooe for pitched roof i-n 4 span to

1 height or 2:1 slope. This gives an Inclination of 26,5°,

Both the windward and leeward slopes, will, therefore, be

subject to suction forces. This calls for secured fixing

x>f the rafters to the walls and the covering sheets to the

rafters. A wall plate runs on the top of the walls parallel

to the ridge and rafters are generally nailed to it. The

roofs usually have projections at the eaves to ensure that

the rainwater from the roof does not drip down the walls.

The presence of these projections may alter the distrlbation of wind pressure on tlie roof and there is a possibility

of increase in the suction force due to these projections.

0^20° J p s

30«^^^60° : p = ^^>60° J p =
- 22 -

It has been observed in recent cyclones that most of the

failures of roofs were due to the wind having gone insirle,

pressed from underneath and lifted up the roofs.
Fig. 1 Lay-out of a typical Rural house
HOUSE PLAN

Scole: 14". 1-0"

Fig. 2 Details of a typical Rural house with bamboo
ill

i iili

SIDE ELETVATION

,3"x2'i Wall Plate

SeCTION A-A

A

iKutcha floor

ROOM

Pucccifloor

Ku tcha f(

ROOM

puceo floor 8'-9"x 17'-||"

4

8'- 4" 10

^

" 8

4 19'- 2"

purlin

VflVlVs" Iron Clamp

3"X2"Wall Plaie

1 PLAN

Fig. 3 Details of a typical low cost house with brick walls
BANGLADESH

Scale: 1 = 50 miles

FIG. 4 Area distributfon of nor*wester squalls ( March ) (Figures indicate total no. during the period 1955-61}
BANGLADESH

Fig, 5 Area distribution of nor'wester squalls ( Apr'il

)

(FTgures indicate total no. during the period 1955-61)
BANGLADESH

I rig. 6 Area distribution of nor'wester squalls (May)

(Figures indicate total no. during the period 1955-61)
Fi'g. 7 Area distribution of nor wester squalls ( June)

(Figures indicate total no. during the period 1955-61)
rfg. 8 Storm tracks in the Bay of Bengal

A-ffecting Bangladesh
BANGLADESH

Scale:i =50 miles

Area wind force more than lOOmiles

per hour

Wfnd of hurricane force 80 - lOO miles

per hour

Wind of gale force 40- 55 miles

per hour

9 Typical cyclone in Bangladesh

( 9th May, i96i

)
I
APPENDIX E

HOUSING IN EXTREME WINDS

E-1

Housing

in extreme

winds

A study of the Socio-Economic and

Architectural Aspects of Low-Rise,

Low-Cost Housing in three High-Wind

Geographic Areas.

Submitted to the Office of Federal

Building Technology, Center for

Building Technology, National Bureau

of Standards, Washington, D. C. 20234

Report

Windstorms are considered by most sources to be the

most destructive of natural forces. A survey of damage

inflicted in the Philippines, for example, by cyclones

alone between 1948 and 1971 shows an average of fatalities close to one thousand persons per year, and annual

property losses of some $10 million. In Bangladesh, the

infamous typhoon of 1970 killed a far greater number of

people through the floods it generated.

This draft report reviews the socio-economic and the

architectural aspects of low-cost, low-rise housing

in three developing countries subject to extreme

winds: the Philippines, Jamaica and Bangladesh. It

is based on a review of 5 key and 9 supporting

publications listed in the References section of the

report

.

A final report will include a review and study of

many additional documents, and from discussions and

correspondence with appropriate officials in the above

developing countries; the text will be adjusted in the

light of that review.

The group of basic documents that are the basis for

this draft report none the less provide a good solid

profile of housing in those three developing nations.

For the reader's convenience, the information is

arranged under two headings

:

1. Socio-economic factors in the three countries.

2. Housing characteristics.

1
Contents

la. General data/

3

Socio-economic factors/4

Housing characteristics/ 11

lb. Review by country/ 18

The Philippines/ 19

Jamaica/ 24

Bangladesh/ 30

2. Conclusions/ 35

i

3. References/37

2
General data

3
317 453 1361

Socbeconomic

factors

The safety aspects of low-cost, low-rise

housing have always been at the mercy of

tradition. Cultural patterns, socioeconomic restraints and technical expertise

(or lack of it) can both enhance and be a severe barrier to innovation. Thus, understanding a nation's socio-economic profile,

the characteristics of its housing and its

administration, is a vital matter.

The comparative socio-economic profile as outlined in Table 1 tells us a good deal.

For one thing, all three countries have a very high density of population. It ranges

from 317 persons per sq. mile in the

Philippines to 1,361 per sq. mile in

Bangladesh, one of the highest in the world.

Compare this with the U.S. density of 56 and

the USSR, which has only 26 persons per sq.

mile

.

These figures do not tell us the whole story.

In all three of these developing countries

there is a strong migration from the country

to the cities. The major cities in all

three have teeming squatter towns.

In the Philippines, one person in 16 lives

in squatter towns, which as of 1970 were increasing at the rate of 12 percent a year.

In Jamaica, squatter towns are illegal but

growing.

4
^

Table 1: COMPARATIVE CHART OF SOCIO-ECONOMIC CHARACTERISTICS

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5
Over and above all this, the populations have

been rising at a steady rate, from a low of

1.46% per year in Jamaica (which has suffered

emigration of its most skilled workers) to

2.6 percent per year in Bangladesh and

slightly over 3 percent in the Philippines.

Furthermore, even though infant mortality

has been dropping and lifespan rising through

improved health care, citizens in these

countries tend to live less long and this has

led to a very high proportion of youngsters

under 15 years. (For example, in a not

untypical part of Kingston, Jamaica, known

as Delacree Pen, nearly half the population

is under 15)

.

By tradition and necessity this has forced

onto housing such normally distinct functions

as day care, education and play to accommodate

this many youngsters.

•There are other ramifications to these

population patterns. The economics in all

three countries are highly labor intensive,

so that children are in the Philippines, for

example, seen as an economic asset. Family

planning efforts designed to bring population

more in line with food and other resources

run up against this barrier. This is especially

true in rural areas where agriculture is the

main source of income.

Despite city migration, most of the populations

are still classified as rural (68% in Philippines,

90% in Bangladesh, over 60% in Jamaica).

•Several other socio-economic factors stand out

strongly. Foremost is the tremendous over- crowding of available housing. In the

Philippines, average household size is 6

persons. The typical household has only two rooms (in Manila three) . The median number

of persons in a room in the Philippines is

2.7. In Bangladesh, the average number is

3.2. It is common for several generations

(so called "extended families") to make up a single household.

•There are these other factors: shortage of

funds, markets not large enough to stimulate

economics of scale in prefabricated construction, undeveloped transportation and

distribution systems, a shortage of skilled

labor and, by and large, low standards of

workmanship

.

6
Another factor is the resistance by the

population to certain construction materials

and systems. Adobe blocks are not considered

"noble" when compared with brick or stone

in many countries.

An experiment carried out in Peru some years

ago using igloo-shaped houses made of

polyurethane were rejected because families

were unhappy with the lack of corner areas where one could put "things out of the way",

predictably bad interior acoustics, and a lack of normally defined property lines in

which to fence in animals. They were

eventually abandoned.

Most families cannot afford housing on the

open market and in many cases not even housing subsidized by the government. With

some exceptions, private housing is better

so far as wind resistance is concerned, but

those who cannot afford housing of any kind

range from 65% in the Philippines, 67% in

Jamaica up to a high of 72% in Bangladesh.

Consequently, the very poor must fall back

on government public housing programs

(which are modest in all three countries)

or build their own housing according to

demonstrably unsound wind-resistant

principles

.

• Squatter settlements

Squatter settlements tend to be the fastest

growing areas in cities and often cover a quarter of the city area. They can be put

up fast to meet demand. In essence, it is the

squatters who are providing a housing solution,

and the sense of community and morale are known to be high.

A policy that is becoming more and more

accepted is to focus on improving squatter

settlements. This is done by providing so called " site and services ". Land, water

supply, electric power and waste disposal

are provided. Better structures come along

with appropriate help as the settlement

becomes more established. This way, selfhelp is stimulated.

7
• User requirements

Research into user requirements on low cost

housing can help evolve designs that are not

only adequate technically but also meet socio

economic needs. Clearly, as most current

designs do not meet proper wind-resistant

criteria, new designs, quite possibly using

unfamiliar building materials and methods,

will have to be used. As there is no hard

data on user acceptance of such designs,

this information must be sought out.

Mrs. Tarja Cronberg (Ref. 1) uses these sources of information: statistics of the

country's population (death rate, size of

families, average income, etc.); interviews

with local builders, architects, and con- struction workers; and observation.

She divides the information into two classes: user characteristics , and user activities .

Under user characteristics, she determines

the users' typical physiological and

psychological characteristics, plus such

socio-economic characteristics as family

size and structure, mobility, identification

with a particular ethnic, religious or geographic group, and educational background.

Under user activities, Mrs. Cronberg identifies 9 headings:

O Sleeping O Recreation/play

O Food preparation O Social (receiving of

O Storage guests, etc.)

O Personal sanitation Oldentif ication/partici

O Work pat ion

OLearning and orientation

She now feels that more information is needed

in four areas:

O Health standards in existing environments.

O Need for personal space and privacy in

overcrowded housing.

O Social activities in the neighborhood and

community

.

O Activities of specific groups such as children.

8
This determination, done with aid of local

experts, is clearly important in arriving at

a clear, objective set of criteria of how

families in a given milieu are likely to

respond to innovative, wind-resistant

design that is new or unfamiliar.

•Acceptance and rejection

The Cronberg study also indicates that

innovative housing designs and new materials

are widely accepted in the Philippines, even by low income owners. This is true especially where the owner is able to make small

individual changes on his house after he moves in. Most practicing architects and

engineers in the country are said to accept new materials which have the needed properties

and do not cost too much.

The opposite has been the experience in Peru.

Peru is not a part of this report, but is a useful object of study nevertheless. New

construction materials always run into a strong initial period of rejection, and

only a few have survived this reaction and

kept a place in the market (Ref. 1).

Examples of th is rejection include:

OA hollow block based on a Swiss patent

and made up of mineralized vegetable

fibers encased in cement.

OA panel-sized product made of expanded

gypsum.

O Corrugated sheets of glass fiber and

polyvinyl chloride (PVC) . Plastic

bathtubs and basins.

O Sprayed polyurethane igloos developed in

Germany for use after an earthquake (as

discussed earlier)

.

The few construction materials (other than

indigenous materials) that are broadly accepted are corrugated sheets of galvanized steel or asbestos

cement. The former, despite poor thermal

and acoustical properties, are popular

because they are strong, do not weigh much,

and can be easily and cheaply transported

on the backs of mules. The latter, though

superior in thermal and acoustic terms, are quite fragile, and the resulting higher

breakage also drives up costs.

9
•Attitudes to prefabrication

Another Peruvian study with clear lessons for

other developing countries is a 1962 survey

of public attitudes towards prefabricated

housing. It was carried out by students at

the Architecture Department of the National

University of Engineering.

Consumer interest was found to be low because

prefabricated houses cost only a little less

than brick and concrete houses and a good

deal more than adobe houses; they looked too

uniform; and the public did not really

appreciate the savings inherent in the shorter

construction time.

As for builders, they found that a restricted

market led to high sales costs; financing was difficult; and complex transportation sharply

raised construction costs outside the

immediate area of Lima.

Housing economics

Housing approaches in developing countries

have been critized on two grounds.

First, because housing deficits are computed

without taking into account the values or preferences of those to be housed. Secondly,

because the traditional solutions to

housing deficits have turned out to be well

beyond current capital investment rates.

Even in countries that anticipate a high rate

of growth, the competing demands of agriculture, industry, and other programs reduce

the funds available for housing to a level far

below needs (according to a report by William

F. Reps, Ref. 1).

5.7/0

2.8%l

In the Philippines, for example, demand for new dwellings would require a capital investment about 5.7 percent of the gross national

product; in fact, in 1967 only 2.8 percent

was so invested. As a result, slums and

squatter towns grew - 10% of the population

of Manila and 30% of the population of key

other cities lived in squatter areas.

Yet the "sites and services" solution referred

to earlier has been found desirable, especially

in the Philippines, where self help (known as "bayanikan") is widely accepted in the

building of dwellings. It is discussed in

greater detail later in this report.

10
Housing

characteristics

Four ingredients of housing are discussed.

These are: siting, design, construction

methods, and materials.

Siting

With the relatively primitive wind risk maps,

little regard has been given to the placement of houses in relation to danger. Good

site location or orientation linked to local

terrain and natural cover can be, but

usually has not been, determined from historical wind data. This data provides the

frequency, velocity and direction of the

prevailing winds, especially in their extreme

form. Hence, windstorm damage can be cut

back a great deal by placing buildings so they are protected by hills, stands of trees

and other natural elements.

Design

Windstorm resistance can be notably improved

by various simple measures. These include

horizontal bracing of certain types of roofs

over houses made of adobe masonry and other

small unit construction; a more rational

disposition of openings in bearing walls;

reinforcement of critical areas of a building

subject to being overstressed ; and the

strengthening of connections at joints.

11
^^^^^^^

loiterhaI prHSurg^

All this may not be enough. Special studies

on how turbulence in a storm is distributed

are required.

It is possible to make buildings more wind

resistant by improving connection details, by

learning more about the effects of wind

loading on buildings, and by avoiding shapes

or arrangements of buildings in groups so as not to cause undesirable aerodynamic effects.

For this, theoretical as well as experimental/

wind model study research is currently being

conducted as part of this project's research

activities.

Certain design elements can be very unfavorable. Sharp edges, low-pitched roofs, large

overhangs and improper grouping of buildings

will cause problems. Textures, too, are important. According to R. M. Aynsley

(Ref. 1), the aerodynamic behavior of

buildings can be improved by providing rough

surfaces or ribs on the exteriors of walls.

Grass roofs have allegedly served to relieve

pressures, as have smooth transitions

between planes of a house.

Unfortunately, the internal pressures

developed in buildings with openings are usually not considered in design. Roof

failures have been caused by wind which

penetrated the structure and pressed up

on the roof from beneath.

Certain configurations (such as cylinders)

,

or igloo-type structures, are far more

stable than box-like structures, but in the

few places where they have been tried the

cultural attitudes of the population caused

them to be abandoned.

In Bangladesh, a revolutionary type of

design has been tried, using materials and

shapes new to the country. These are integrated roof and wall elements, made up

of units consisting of polyester resin, and

jute. They have performed well in winds

but their final social acceptance is still

unknown

.

12
Construction technique

<9vev <v a rim Cer oMtrOj

11

to ^oliiC ^ItH^t^

In developing countries, it is often hard to

separate design from construction. By and

large, typical characteristics can be

summarized as follows:

•Foundations: Load transmission to soil

becomes less critical since low-rise dwellings

of one or two stories do not generate a high

dead load. Where flooding is not common,

rectangular footings of plain or reinforced

concrete or gravel are used.

In flood-prone areas houses may be built on stilts (e.g. bamboo) driven into the ground

to the appropriate depth. Mat footings are sometimes used on unfavorable soil.

•Walls: Walls are either structural or nonstructural. When non-structural, they merely

serve as an in-fill for a frame and their

constribution to the overall structural

resistance of a building to wind pressure

should be minimal.

Structural walls of wood, concrete, burnt

clay or soil-cement composition are the most common in low-cost housing construction.

Walls are either monolithic or small unit

masonry type, where units are layed in

staggered courses, usually in beds of mortar.

Clay brick and title, adobe brick and

concrete block are the most common masonry

units. Quality control in making these units,

as well as the mixing of the masonry mortar

bed, can make or break the structural

strength of the total wall.

Wind stresses on walls are either plain

bending or in-plane stresses. Out-of-plane

pressures (when wind acts directly at right

angles to a wall) cause deflection and

eventually failure. Tornadoes common in

Bangladesh have pressure drops so strong

and sudden as to cause an actual explosive

action of the wall.

13
i.

tt^ day (^e.trsloQSf

CoC04Lirnit hiA^fM

fvy<6vitir of- Am

20

as

2.0.

h^jhtM^ roof pihhIn-plane stresses are developed in walls which

act as shear-resisting elements within the

building, the plane being parallel to the

wind direction.

Moreover, incorrectly planned wall openings

may be critical, especially at corners. In

any case, conditions where two walls intersect

or between walls and foundation or walls and

roof, require special design due to the high

stresses at those joints.

•Roofs: Roof pitch is an important design

element for good wind resistance. The magnitude of positive or negative wind pressures

on roof surfaces is directly related to roof

pitch. Wind affects roofs in two ways,

direct and indirect.

Direct local effects are made up of high

positive pressures (or suction) over local

areas of the roofs. This may lead to

damage to roofing — whether shingles, tiles,

corrugated sheets, etc. Overhangs, common

for sun protection, are especially liable

to wind damage, as they undergo positive

pressure from below and suction from above.

Indirect effects occur when wind loads are transferred to lateral walls, causing

stresses. If this mix of pressures on the

roof is strong enough, the capacity of the

connections will be exceeded and the roof will

be lifted off. This brings additional danger

since every roof has a structural role as a horizontal diaphragm. This transmits windloads from the front to the side walls. If

a roof is off, both frontal and lateral walls

may collapse.

Flat roofs (especially with overhangs) are more subject to wind damage than roofs with

a steeper pitch. • Prefabrication

Any method that will produce housing more

effectively must, at least in its first

phase, make the best use of available local

labor. And the choice and control of the

dwelling environment resulting from any

industralized housing must not conflict with

individual uses, traditional preferences

and outlook.

14
In the Philippines, few companies make

prefabricated components, including a private firm which produces wall panels

and roof trusses, and a government firm

which makes lightweight concrete panels.

Filipino builders are said to recognize the

savings which pref abrication offers, and

feel they can make it work. Their problems

at present are lack of adequate financing

and too small a volume.

In Bangladesh, reinforced concrete shell

roofs in a shape of a hyperbolic paraboloid

have been used, using one inch pre-cast

reinforced concrete elements, with concrete

connections made on site.

In Jamaica, the most common form of industralized construction consists of large

precast concrete panel systems. Wall and

roof panels are lifted and assembled by

crane. Other forms of pref abrication in

Jamaica use precast posts combined with

precast concrete or timber beams, with

concrete infill "boards" between posts.

Materials

The most commonly used materials of

construction are those that are found

plentiful locally and require little or no sophisticated equipment to convert into

building materials. In Bangladesh 90% of

rural houses (and 90% of Bangalis live in

the country) are made of bamboo, thatch and

mud. Two out of three houses use the same materials for roofs. Only 1 percent of these

houses have walls of concrete, baked brick

or stone, and these are mostly staff

quarters built by the government. The

remaining roofs are of galvanized

corrugated iron or corrugated asbestos

cement sheets. In its cities, only some

27% of housing is considered "permanent

and semi-permanent."

15
Following are other coimnon materials used in

the three nations:

•b.

Soil ; Natural earth is about the most common material used. Sun-dried adobe

bricks have been the basic masonry units

for low-cost housing. These bricks are often untreated against penetration by

water. More recently adobe brick has

been stabilized by the addition of

asphalt. This boosts the durability

and water-repellent properties and is a major breakthrough. The social acceptance,

however, of adobe, stabilized or not,

is still not high.

Wood : Wood, while popular, easy to

handle, versatile and strong in tension,

is not everywhere available. It is useful as a framing material. I'rtien not

available in milled, dimensioned form, it

is replaced by non-dimensioned lumber —

as cane, bamboo, palms and thatch for

structural enclosure and roofing purposes.

Cane, bamboo or split wood are often used

to reinforce adobe masonry. Major drawbacks are moisture, fire and insect

infestation. Chemical preservatives which

can be produced in developing countries

can prevent this kind of danger and

deterioration. Also, chipboard products

are used for walls and ceilings.

Concrete ; Where sand, cement, water and

various additives are plentiful,

concrete is a logical and widespread

local building material. Weak in tension,

it can be reinforced by a local material

such as bamboo as well as by costlier

imported steels and fiber glass. Concrete

reinforced with a wire mesh and known

as ferro-cement has been used with very

little supervision in some countries, and

the materials needed are cheap and usually

readily available.

Brick and concrete block masonry are

common,,

Steel ; As a capital-iiytensive material,

steel is rarer. Its most common use is as a roofing material (in the form of

corrugated sheets of galvanized steel or

16
aluminum) , and to a small extent as connectors for bolting and anchoring the

various structural elements.

#f. Plastics ; Plastics are a highly adaptable

material. Depending on the choice of

components, they can be tailor-made to

adapt to most structural and enclosure

needs of housing. Not enough is known

about the weathering properties of

plastics in outdoor use (as compared

to traditional materials) , especially in

tropical areas such as those in this

study. Use is most advanced in the

Philippines, which also is one of the

chief plastics producing countries in the

Far East. They use native as well as imported raw materials and processing

machinery. Several important tests

underway in Bangladesh are described

later in this report.

Still, plastics are resisted as a new

and unfamiliar material. Solid-seeming

and demonstrably durable materials are preferred. Plastics are likely to be more widely accepted in the future as they penetrate the private, for-profit

housing market and non-housing uses such

as clinics and schools. They can then be

observed and their performance seen by

those who presently must rely on housing

provided by their governments or through

their own labors.

#g. Indigenous fibers , such as palm leaves,

coconut husks and peanut shells have

served as filler materials in spaces

between structural supports or between

roof rafters; and grasses such as jute and

hemp can be used as reinforcement for

concrete or adobe masonry.

17
Review

bycountry

The preceding chapter described the overall

picture of housing in the three countries

of the Philippines, Jamaica and Bangladesh

in terms of socio-economic profile and

physical housing characteristics. The three

sections that follow are based in greater

detail on documents developed specifically

to describe conditions in each of these

three countries. In this sense, this

chapter should be seen as an extension of

the preceding one.

18
The Philippines

The Philippines is said to have the highest

frequency of tropical storms in the world.

Average annual frequency is 20.

Filipinos have always depended on water

(whether river or salt) for food, transportation and for watering their fields.

This is still the pattern in rural areas. This attachment to low land and water

logged areas led to a unique type of

dwelling, with a raised floor on stilts.

Communal activities centered around the

houses of the village elders, who also were religious and judicial officials.

This organization has today been formalized

into the barrio, which is the lowest

political unit of government.

•The Filipino family and its housing needs

The family is the strongest unit of society.

Typical of the family system is bilateral

kinship. This is extended often as far as the third or fourth cousins. Families with

at least three generations are common. In

times of crises, family members are expected

to share board and shelter with less fortunate

members, especially parents in old age and

widowed relatives with children. The family

acts as the economic unit in rural and urban

areas. Children are seen as economic assets.

A large family is regarded as a means to

social security.

19
• The community

The term "barrangay" exists to define this

conscious sense of belonging. It is a pattern

into which the activities of the family units

are woven. Extended families exist not only

in the country but also in cities. Their

percentage in low income areas around Manila

is said to reach 55 percent. Family size

ranges from 7 to 11 in these cases, with at

least 18 percent made up of 9 members or more.

Only 12 percent of urban families can afford

housing in the open market; 23 percent can afford home ownership provided they receive

long-term financing at low interest rates.

The remainder cannot afford adequate shelter

even at reduced rates.

Ranking cities in the Philippines have between

10 and 45 percent of their populations in

slums or in squatter areas; the national

average is 5 to 6 percent. Filipino squatters

are not said to be shiftless people, but well

motivated and resourceful.

A study made by Jaime Laya, Remedios Balbin

and Romulo Neri of the Agno-Leveriza

squatters area of Manila (Ref . 10, part H)

paints a grim physical picture. Eight

hundred dwellings are crammed into two city

blocks behind a prosperous seeming facade of

solid apartments and houses. Most structures

are of one or two rooms, without running water

or toilet. 11.5% of surveyed heads of household were unemployed, compared to a 1969

national average of 7.3%.

Yet the study team noted little active discontent; rather, they found an attitude of

initiative, of moving on by one's own effort

and enterprise. Education level was relatively

high (7.1 years of schooling on average for

heads of household, more than needed for the

jobs they hold), and income level varied

widely, from destitute all the way to

families with a refrigerator, television set

and telephone service.

Another study, by Mary R. Hollnsteiner

(Ref. 10, part I) confirmed a sense of excitement among squatter families after they left

a dull rural existence and moved towards

20
economic opportunity in the city. One

recommendation of this study, which looked

into options for relocating Manila squatters, was to weigh with care any plan for moving

families off to a site too remote from urban

job opportunities.

The estimated annual need for urban housing

alone averages 100,000 units — to accommodate

population increase, new family formations

and replacement of squatter dwellings. The

cost of land is high and this has a direct

effect on the high cost of adequate housing.

In addition, wholesale and consumer product

prices grew sharply between 1970 and 1973.

The average increase for all commodities was

25 percent; for most construction materials

the figure was 40 to 60 percent.

This does not jibe with other, more optimistic

reports which indicate that materials and

skilled labor for conventional construction

methods are said to be fairly available. The

cost of delivering materials is reported low

because production is spread throughout the

country

.

Economic aspects

Only 12 percent of the population (with annual

family income over $1490 — U.S. dollar

equivalent based on exchange rate of the

Philippine peso as of August 9, 1974) can afford housing on the open market. (Ref . 10,

part A)

.

23 percent can afford to own a house if

offered long term cheap financing with modest

land, development and construction cost ($596

to $1489 annual income range)

.

The rest cannot afford shelter at any cost.

Investment in housing rose from 2.8 percent

of GNP in 1967 to 4.0 percent in the early

1970' s. But to meet the country's housing

need of some 470,000 units per year, an allocation of 5.7% be required.

Yet the Filipino economy as measured by its

GNP has risen at an average annual rate of

6.6 percent from 1968 to 1973. Average per

capita income ($130 in 1970) also rose, and

is expected to double in the next 10 to 15

years

.

21

I i 60/1

\mt fcrtCfl. a,s vyucl\
The amount a family can afford for housing

varies chiefly with its income and location

along with other lesser factors. For example,

according to a study by Sixto L. Rojas III

(Ref . 10, part F) , a family with an annual

income of $300 can afford a house 1.3 times

its income, or $390. At an annual income of

$450, it can afford a house of 1.8 times

its income, or $805. This sets certain

numerical limits on the cost of low income

housing

.

In addition, income varies in different

regions of the country, with families in

urban areas outside of Manila having a higher pattern of income than Manila and

rural areas (Ref. 10, part F) . All these

economic aspects are important in determining

realistic parameters for the design and

construction of low-cost, wind-resistant

housing.

•Housing characteristics

Some key housing characteristics are shown

in Table 2. Note sharp differences between

statistics for metropolitan Manila and for

the Philippines as a whole. They are based

on surveys by the Bureau of the Census and

Statistics and by the Population Institute

National Demographic Survey. They give

little idea of the actual condition of the

dwellings themselves.

22
Table 2: KEY HOUSING CHARACTERISTICS IN THE PHILIPPINES (Ref. 2)

Part 1. TYPE OF DWELLING UNITS BY STRUCTURE (PERCENT)

Type Metro Manila Philippines

Single Family Dwelling 57.6 78.9

Duplex 5.5 4.1

Accessoria 15.1 2.3

Apartment 8.1 1.1

Barong-Barong (shack) 4.4 5.4

Commercial Building 1.0 1.3

Other or No Response 8.3 6.9

Part 2. NUMBER OF ROOMS IN HOUSEHOLD EXCLUDING BATHROOM AND TOILET

(PERCENT)

Type Metro Manila Philippines

One Room 11.3 14.1

Two Rooms 22.5 28.4

Three Rooms 23.1 25.7

Four Rooms 19.8 14.3

Five Rooms 8.0 6.5

Six Rooms 3.8 2.6

Seven Rooms 1.3 0.8

Eight or More Rooms 1.6 0.6

No Response 8.7 7.0

Part 3. DENSITY (PERSONS PER ROOM) WITHIN HOUSEHOLD (PERCENT)

Type Metro Manila Philippines

Less than one person

per room 5.1 6.1

1.00 to 1.99 persons

per room 27.8 27.4

2.00 to 2.99 persons

per room 26.5 25.4

3.00 to 3.99 persons

per room 14.1 13.7

4.00 to 4.99 persons

per room 7.7 7.7

5.00 to 5.99 persons

per room 4.2 3.7

6.00 to 6.99 persons

per room 1.5 2.8

7.00 to 7.99 persons

per room 1.8 1.7

8 or more persons per room 2.7 4.5

No Response 8.7 7.0

23
Jamaica

•Socio-economic aspects

Virtually all Jamaican housing built by the

private sector today falls outside the

definition of low-income housing, that is,

the cost of house plus a developed site must

be under $5,500 (U.S.). Whereas 350 to 450

sq. feet is said to be a minimum standard

for social housing in developing countries,

a more attainable standard for people with

no fixed income brings this closer to 200 sq

feet. In such cases, provision is usually

made for the owner to extend the house at some future date.

Traditionally, urban low-income housing has

been in the form of high-density apartments

terrace houses or small groups of houses

closely clustered around a communal yard.

Detached houses have been more typical of

middle income groups , and have become the

goal of upwardly-mobile low-income groups.

Over the past 10 to 15 years, this has

caused developers of low-cost housing , in

order to keep prices down, to erect

groupings of closely spaced, single-story

detached units on tiny lots.

Oddly enough, a middle income trend back

to apartment living is seen as encoviraging

a similar trend among low income groups;

these may now be more likely to accept

multi-story and terraced housing, with its more efficient use of limited land and resources

.

24
f|06£

A useful if not totally representative

picture emerges from a survey of housing

conditions in the Delacree Pen district of

Kingston (Ref. 8). Delacree Pen is the site

of an urban renewal project. The survey

disclosed among other things that:

O Of the A, 935 households, 68 percent lived

in one room; 18 percent in 2 rooms and

8 percent in three rooms. The most common

household size was from 5 to 7 (24 percent)

;

37 percent were of one or two persons, and

11 percent had eight or more members.

Construction costs have gone up due to a 1973 money devaluation and higher labor

costs, with 70 percent of Jamaican outmigration consisting of skilled labor.

•Housing characteristics

(See also Table 3)

Jamaicans by and large prefer concrete houses

and do not like houses made of light-weight

materials, unless forced to do so for

financial reasons (Ref. 4). Until recently

there has been a bias against precast concrete

houses (especially those of thin crosssection) but this is disappearing.

The most popular material among all income

groups is hollow concrete block masonry.

Physically, low cost housing in Jamaica

falls into six types (Ref. 4).

01. Wattle and daub (4%)

;

Until the 1930'

s

rural owners built most low-cost houses in

this fashion. The framework of wooden posts

and beams, with sticks interwoven horizontally

between the posts, was the wattle. This was

daubed inside and out with mud from available

clay, to create solid walls. The roofs were

pitched and made of a thatch made from

bundles of dried leaves and tied in place.

02 . Timber stud and horizontal boarding

(36.9%) ; Roofs were pitched, made of timber

rafters covered with corrugated iron sheets

or wooden shingles.

25
Table 3: KEY HOUSING CHARACTERISTICS IN JAMAICA (Ref. 4)

Part 1: DISTRIBUTION OF DWELLINGS BY TYPE OF TENURE (PERCENT)

Type of Tenure Total Urban Rural

Owned 52.4 29.7 70.8

Leased 2.5 3.9 1.4

Rented 36.5 59.9 17.6

Rent-free 7.9 5.8 9.6

Squatter 0.4 0.5 0.3

Other 0.3 0.3 0.3

Total 100.0 100,0 100.0

Part 2: DWELLINGS CLASSIFIED BY TYPE

Type of Dwelling Number Percent

Separate house 327,656 78.0

Flat /Apartment 67,083 16.0

Barracks 3,223 0.8

Out-Room 4,069 1.0

Part of Commercial Building 11,765 2.8

Other Private 3,886 0.9

Other 2,477 0.5

Total Dwellings 420,159 100.0

Part 3: PERCENTAGE DISTRIBUTION OF DWELLINGS BY NUMBER OF ROOMS

of Rooms Total Urban Rural

1 32.7 42.3 24.9

2 26.3 19.6 31.7

3 16.1 11.7 19.7

4 8.5 7.5 9.3

5 5.3 5.9 4.9

6 2,8 3.3 2.4

7 2.6 3.4 1.9

8 or more 5.8 6.3 5.3

Total 100.0 100.0 100.0

9fi
03. Brick or concrete nog (11.8%); Like the

preceding, these are typical of urban areas. Wood studs receive a brick or concrete infill

or "nog" and are covered with a lime or cement

plaster. Houses are usually raised two or three feet above ground.

A3. 4% of Jamaican housing is concrete-based:

04. Hollow concrete masonry: Blocks are manufactured locally: cavities are filled

with concrete during construction, and steel

bars are added to reinforce against wind and

earthquake. Poured in-place reinforced

concrete stiffener columns should be included

in panels over 16 feet long, but are often

omitted in low-cost housing. Reinforced

concrete belt beams are used to cap walls at

roof levels.

05 . Large-panel precast-concrete systems : Single panels can extend to the full length

and height of a unit. Wall and roof panels

are lifted by crane and connected by welding

at matching steel inserts. (These systems

are not strictly speaking "low-cost" but

could be if one steps up volume of production

and accepts a lower standard of finishes)

.

06. Small-unit precast concrete systems : Precast concrete posts are combined with

precast concrete or timber beams, with an

infill of concrete "boards".

Remaining housing is of brick or stone.

•Housing programs

Except for the 20 percent of needed units

supplied or aided by the government (Ref . 5),

there is presently no machinery for providing

housing for the very bottom of the income

scale. The mechanism used is either the

continuing growth of shanty towns or the

creeping subdivision of existing houses to

accommodate new households.

On the other hand, the government now has

underway a "site and services" project

which selects land; provides an "infrastructure" of utilities; a minimum

core unit; certain community facilities such

as a school; possibility of emplojmient and

skill training.

27
Families with an annual income of less than

$1650 (U.S. equivalent) are eligible (Ref . 4).

The goal is to provide 6,000 serviced lots in

the next three years. Lots are to be available in three options:

Owith connections for electricity, watersupply and sewerage, plus materials for a toilet-kitchen-shower core unit.

Othe same, but with a built core unit, plus

materials for shelter and enclosure for

the rest of the house.

Othe same as the preceding, b ut with the

core-unit and shelter being built, and

materials only provided for enclosure of

the rest of the house.

Serviced lots are to be owned on a leasehold

basis, and loans for materials will be

provided through credit unions.

Although the main focus of the Jamaican

government is on "sites and services,"

there are other government programs. These

consist of a mix of government-built housing

for sale or lease (1970-1975 goal: 3,125

units); owner-occupied, government subsidized

units (3,600 units); rural housing projects

(4,880 units); indigent housing built on

land owned by recipient (2,250 units); urban

renewal projects focused on Kingston

(4,876 units); plus assistance furnished,

to housing cooperatives (Ref. 4). •Wind patterns

Despite the frequency of hurricanes in the

Caribbean, direct hits on Jamaica are few

when compared with the number of tropical

storms which pass within 150 miles of the

island (Ref. 4).

On the other hand, near misses are often

accompanied by flood-rains which cause much damage. Records made between 1886 and

1967 show that the paths of 19 hurricanes

and tropical storms passed directly over Jamaica and those of 98 (48 of them having

hurricane force winds) passed within 150

miles of the island (Ref. 4). About onethird of the latter brought about flooding

and damage

.

28
Reporting on wind damage caused by the

latest "direct hit" hurricane of 1951,

The Daily Gleaner , a Jamaican newspaper,

noted damage at $56 million (1951 prices);

- 20,000 buildings were destroyed and the

death toll was 150. In St. Thomas Parish,

90 - 100% of homes were demolished.

Most of the recorded wind damage occurred

to poorly built wooden low-income houses

with corrugated iron roofs over wood

^ rafters

.

29
Bangladesh

6, CoM^hed

• Socio-economic aspects

Bangladesh has one of the largest densities

of population in the world. Measured by

gross domestic product, it is also one of

the world's poorest countries. 90 percent

of the population is rural, and industrial

output accounts for only 9 percent of the

gross domestic product (mostly jute

processing). (Ref . 9)

The last housing census was done in 1960;

results from a new housing census are to

be ready sometime in 1974. As Table 1 shows,

the average number of rooms in 1960 per household was 1.77. 53 percent of householders

lived in single room dwellings, and the

average density of occupancy was 3.2 persons

per room. In the case of 31 percent of the

population, five persons or more share a room. Clearly, any damage from intense

windstorms risks major casualties to a population as densely crowded as this.

The rural population lives in the patriarchal

family compound. When sons marry, a new room is erected for the new household on the same field as the parents, next to the

parents' house. Thus, houses occupied by

families that are paternally related are grouped together. These clusters provide

shelter to families numbering as many as 40

members; even higher figures are common. Houses are usually surrounded by dense trees

and other tropical vegetation. • Housing characteristics

O Rural

;

The rural population is divided

into land owners and landless laborers.

One out of five villagers is landless. ; The average land owning villager has 1.5 acres and usually rents another acre from

well-to-do villagers. Houses tend to

be scattered throughout the village.

30
Typical rural kiM^

corruACiCerti f rav\ root •

Rural houses are known as "kutcha" or raw

structure, with a plinth made of mud, and

walls and roofs of bamboo, straw and

leaves. These houses need to be maintained

constantly and seldom provide safe shelter

against rain and wind. 90% of rural houses

are built this way. Only about one in a hundred has walls of concrete, baked brick

or stone. About one house in three has

roofing made of corrugated galvanized iron

or asbestos cement.

O Urban; As 72 percent of the urban population can't afford to pay rent for even the

cheapest housing, they live largely in

flimsy shacks, mostly in so-called "bustees'

and squatter settlements. This housing is

made of bamboo, often consisting of a piece

of woven split bamboo fencing bent in the

shape of a semi-circle. Headroom is low

and occupants spend most of their time

outdoors. Even moderate winds blow these

houses away despite efforts to hold them

down by putting counterweights on roofs.

To rehabilitate these squatters the

government has built some 4,500 semipermanent one-room houses on the outskirts

of Dacca, the capital.

The stronger urban houses are mostly made

of burnt clay brick walls, with flat

reinforced concrete roofs. As the walls

are usually 10 inches thick, gravity

usually precludes failure through wind

stresses. Failures occur largely due to

substandard mortar or poor workmanship.

No damage to the flat roofs has been

reported, except in cases of projecting

sunshades

.

• Other types of housing

O So-called CARE types (named after the

U.S. relief organization) use soil cement

blocks and corrugated iron sheets for roofs.

Units roughly the size of an American concrete

block are made in a simple-to-use machine

which compresses a mixture of 90 percent

non-saline soil and 10 percent cement to

make about 300 blocks a day. A typical

house requires some 1200 blocks. The

essence is selfhelp, as a minimum of skilled

labor is needed to put up this kind of house.

The key to wind safety is to properly anchor

the roof to the block walls. This type of

structure is very popular in the country.

31
CARE has also developed a new composite

building material, made of pulp from the core of the jute plant, jute cloth and a plastic resin for binder and facing. This

seeks to combine a locally plentiful

material (jute) with synthetic binders which

can be manufacturered into panels by domestic

industry

.

Several variations of material and configuration have been formulated for laboratory

testing, prototype construction and wind

testing of full-scale units.

Four prototypes have been developed so far.

These are:

1. A pie-shaped, domed structure made of

a 3/4 in. compressed jute-waste board faced

with polyester resin and glass. Public

reaction was good until the facing was identified as plastic, for plastic was identified

in the public mind with a brand of cheap and

brittle crockery. Those who acknowledged

the strength of the plastic nevertheless

faulted the house for its roundish dome-like

shape. This made partitioning difficult and

made it unsuitable for low-income families —

especially the 80 percent Muslim families

with their tradition of isolating women in one part of the house.

2. A self-supporting house, rectangular in

plan and with an elliptical roof profile,

with curved panels made of the same combination of synthetic resin and jute. No

component was to weigh more than 100 lbs.,

so it could be easily managed by two men.

It was designed to resemble traditional house shape

3. A structure using the above materials

but geared for use in larger, non-residential buildings.

4. A structure designed to substitute the

jute/plastic material for the traditional

thatch or corrugated metal roof and its

customary wood or bamboo support rafters.

The new roof of this prototype was designed

to fit over either traditional or new walls.

fj I A .4 ' A

These four prototypes can be anchored

I H> fB'tepC. 4 C4 oC^t^KAA- directly to the soil or to standard

& fce^ TtiC^C Cci'fiA Iu-*>C- Or—) perimeter footing foundations.

32
Many of these prototypes have been used for

other than residential purposes, and as such

have been very popular. These uses have

included a medical operating theater,

dispensary and office. From a socio-economic

view, this is seen as a useful lesson, in

that citizens of Bangladesh can get to know

the structures in a service role without

having to accept them suddenly into their

personal lives as homes.

Two additional CARE prototypes of more

traditional appearance were developed in the

United States using a panel made of a jute

reinforced polyester core and a fiber glass

reinforced polyester facing. The 10 ft. x

20 ft, two room units successfully passed severe simulated wind and water tests. (Ref . 14).

O Reinforced concrete shell roofs of

hyperbolic paraboloid shape have been used

for industrial and suburban housing. The

roof is anchored to the supporting brick

walls by means of half inch mild steel bars

at the corners. •Housing programs

The 1971 war of independence left about 2 million families homeless. Sizeable housing

rehabilitation and reconstruction efforts

are now under way in rural areas. Some

175,000 houses were to be put up in coastal

areas in 1972 and 1973.

A far-reaching decision was for the government

to decide to put up two-story cyclone

shelters in coastal areas. These would also

serve as schools, health clinics, post offices

and community centers. Some 18 national and

international relief agencies have undertaken

to put up housing, with a target figure of

just under 400,000 units. 225,000 of these were completed by August 1972. •Wind patterns

The most common sources of wind in Bangladesh

are the cyclonic typhoons, tornadoes and

norwesters. Damage is not only from wind

pressures but from heavy rain and storm surges

or high walls of water. Thus, the cyclone of

November 12, 1970 caused storm surges some 25

fee-!; high; nearly 100 percent of the kutchas

to brick, buffC

33
and semi-permanent houses were demolished in

the area of the storm. The coastal areas of

the country are the most vulnerable to

cyclonic storms.

Tornadoes are the most destructive storms.

They usually happen on land during the warm

season in flat areas, with few natural

barriers to hinder them. 200 mph winds are

common, but maximum wind speeds up to 500

mph have been estimated by some experts.

34
Conclusions

A clearcut picture of problems, needs and

solutions emerges from the diverse research

reports, surveys and statistics that served

as a basis for this report:

•As to the socio-economic aspects of designing

wind-resistant low-rise low-cost housing, the

cultural characteristics and financial

capacity of low-income groups must be taken

into account along with the technical

criteria if sound solutions are to stand

the test of widespread acceptance.

This does not mean that new, stronger and

less costly materials and construction

techniques must blindly imitate traditional

forms and processes. Nor, on the other

hand, should these ignore the long traditions

of indigenous building in the three

countries of this report.

#One emerging result of new low-cost housing

tests in Bangladesh bears watching. The

interim use of new prototypes for other than

residential use , in a highly visible way as clinics and community offices, points up a viable way of exposing new forms and

materials to prospective users before they

must take the big cultural step and live

in them as families.

•Similarly, the so-called "sites and services"

approach, if tailored closely to the

characteristics and outlooks of the

communities involved, can capitalize on the

proven initiative, ingenuity and hardiness

of squatter and similar families. This will

help overcome the chronic barriers of

insufficient financial and material resources

in developing countries

.

35
•Closely allied with the thinking behind "site

and services" is the wisdom of gearing

innovations in materials or method to the

relatively plentiful labor supply in most

developing countries.

•This does not preclude prefabrication, but

places new focus on the need to identify,

produce, adapt or combine cheap local

substances made from natural earth, trees

and plants. Bamboo, various kinds of soil,

as well as jute, hemp, cane, split trees,

straw, peanut shells and coconut husks

are among materials that have been combined

with manufactured substances such as cement,

plastics and metals to produce inexpensive,

sturdy building materials.

#How the building blocks are assembled is one

of the major touchstones for stably wind

and water damage resistant houses. The

chief caveats are adequate anchorage of

roofing materials and trusses (if any) to

walls. Structural design of roof members,

splices and joints must accommodate high

wind velocities. Anchorage of houses to the

ground must be designed to prevent overturning; and wall openings must be placed to

avoid weakening the structure at vital

points and to prevent wind from entering and

exerting interior upward pressure on the

roof

.

Similarly, design features such as roof

pitch and overhangs must observe latest

findings on positive and negative wind

pressure distribution.

•Proper placement of houses in groups as well

as to accommodate prevailing wind direction

and land features will always raise the wind

damage resistance of houses. This should be

one of the first criteria to observe when

planning houses in areas subject to extreme

wind

.

This information, when supplemented by the

results of NBS' wind research project, will

provide the realistic criteria needed to

improve wind-resistance of low-cost, lowrise housing.

36
References

Many of the following studies and reports contain additional references,

varying from two or three to as many as seventy five.

(1) "Design, Siting and Construction of Low-Cost Housing and Community

Buildings to Better Withstand Earthquakes and Windstorms, " William F. Reps

and Emil Simiu, editors. National Bureau of Standards, US Department of

Commerce, 1974. 133 pp., ill.

(2) "Socio-Economic and Architectural Considerations in Housing, " by Geronimo

V. Manahan and Josef ina M. Ramos, Building Research Service, University

of the Philippines. 1973. 11 pp. Report prepared for International

Workshop on Development of Design Criteria and Methodology for Low-Rise

Low-Cost Buildings to better Resist Extreme Winds, held in Manila 14-17

November 1973.

(3) "Research Study of the Socio-Economic Aspects of Low-Cost Housing in the

Philippines

.

" Progress report prepared for National Bureau of Standards,

US Department of Commerce. 1972.

(4) "Low-Cost Housing and Extreme Wind-Related Problems in Jamaica" , by A. D.

Adams, consulting engineer. 1973. 25 pp. , ill. A two-part report

prepared for the National Bureau of Standards.

(5) "Economic Survey"

,

by National Planning Agency, Jamaica. 1972.

(6) "The Geography of Jamaica, " by Jamaica Information Service. 1972. Unpaged.

(7) "The People of Jamaica," by Jamaica Information Service. 1972.

(8) "Survey of Housing Conditions in Delacree Pen." Continuous Social and

Demographic Survey Unit, Jamaica. 1969.

(9) "First Report on Low-Rise, Low-Cost Housing and Extreme Wind-Related

Problems in Bangladesh, " by Dr. Jamilur R. Chowdhury, Department of

Engineering, Bangladesh University of Engineering and Technology. November

1973. 31 pp. ill. Prepared for National Bureau of Standards, US Department

of Commerce.

(10) "Housing in the Philippines." Preparatory materials for the Conference

on Housing. National Economic and Development Authority, Philippines. 1973.

(11) "Design of Low-Cost Housing and Community Facilities, Vol. 1: Climate

and House Design ," by Otto Koenigsberger , Carl Mahoney and Martin Evans.

United Nations. 1971. 93pp., ill.

37
"Report of the International Seminar on Low-Cost Construction Resistant

to Earthquakes and Hurricanes. " United Nations. 1971. 59pp.

"Special Report on Techniques of Aided Self-help Housing —> some examples of U.S. and overseas experience," by Ervan Bueneman. Office

of International Affairs, HUD, 1973. 24pp.

"Major Breakthrough in Low-Cost Plastic Housing using Jute-reinforced

Polyesters: the CARE/Winfield/Bangladesh House, " by Armand and Barbara

Winfield. Proceedings, 29th Annual Technical Conference, Reinforced

Plastics/Composites Institute, Society of Plastics Industry, Inc., 1974.

38
Prepared by

Stephen A. Kliment AIA

663 Fifth Avenue

New York, New York 10022

August 16, 1974

NiS-lUA (NEV. 7.73)

U.S. DEPT. OF COMM. ]. PUHl.K .A TION OK RIMH^iIM' NO 2. Gov't Accession

BIBLIOGRAPHIC DATA tmcTn ia cc-i f^"- SHEiET NBSIR 74-567

3« Recipient's Accession No.

4. TITLH AND SI IH IT1.1-: FY 74 Progress Report on Design Criteria and Methodology for

Construction of Low-Rise Buildings to Better Resist Typhoons

and Hurricanes

S. Puhl if at inn Dfifp

Jxily 1974

6. Performing Organization Code

7. AUTHOR(S)

Raufaste, Noel J.; Marshall, Richard D.

8. Performini^ Organ. Report No. NBSIR 74-567

9. PERFOR.MING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Proiect/Task/«'ork Unit No. Center for Bldg. Tech.

11. Contract/Grant No. PASA No. TA(CE) 04-73

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

United States Agency for International Development

Department of State

Washington, D. C. 20523

13. Type of Report & Period

Covered

Final FY74

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

This report gives the major accomplishments of the second phase of a three year

project to provide engineering and technical assistance to the Agency for International Development (AID), Department of State in developing improved design

criteria for low-rise buildings to better resist extreme winds. During FY 74,

the Center for Building Technology project staff members commenced several tasks,

These tasks will serve as major inputs to the development of improved design

criteria. The principal tasks include: 1) selecting a second and third field

test site in the Philippines, 2) instrumenting four full scale houses, at the

sites, 3) instrumenting the University of Philippines wind tunnel facility,

4) participating in an International Workshop at Manila during November 1973,

and 5) developing, in conjunction with short-term consultants in Bangladesh

and Jamaica, a methodology for the transfer of technology.

17. KEY WORDS (six to twelve entries; alp/iabejical order; capitalize pnly the first letter of the fjrst key word unless a proper name; separated by semicolons ) Buildings; Construction; Data acquisition equipment.

Design criteria; Extreme winds; Information transfer; Instrumentation; Wind loads;

Wind tunnel modeling

18. AVAILABILITY Unlimited

I

' For Offi cial Distribution. Do Not Release to NTIS

CI_ Order From Sup. of Doc, U.S. Government Printing Office Washington, D.C. 20102, SD Cat. No. CH

9'^'''^'' '^'o'n N.itional Technical Information Service (NTIS)

Springfield, Vir>;inia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

267

22. Price

USCOMM.DC 29042-P74