OBSERVATIONS ON THE BEHAVIOR

OF BUILDINGS IN THE ROMANIA

EARTHOUAKE OF MARCH 4, 1977

A111D3 DflflTbfl

NATL INST OF STANDARDS & TECH R.I.C.

A1 11 03088968

Fattal, S. George/Observations on the be QC100 .U57 NO.490, 1977 C.I NBS-PUB-C 19

NBS SPECIAL PUBLICATION 490

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OCT 5 1977

Observations on the Behavior of Buildings

in the Romania Earthquake

^ of March 4, 1977 %

George Fattal, Emii Simiu, and

Charles Culver

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

Sponsored by:

Agency for International Development

Department of State Washington, D.C. 20523

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

/ ^ NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

Issued September 1977
Library of Congress Catalog Card Number: 77-600035

National Bureau of Standards Special Publication 490

Nat. Bur. Stand. (U.S.), Spec. Publ. 490, 168 pages (Sept. 1977) CODEN; XNBSAV

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PREFACE

Following the destructive earthquake of March 4, 1977, the Government

of Romania requested U.S. technical assistance in connection with determining the safety of damaged buildings, major dam sites and hydroelectric

stations. The Office of Foreign Disaster Assistance, Agency for International Development (AID) dispatched a team of engineers, geologists and

seismologists to Romania on March 12, 1977 in response to this request.

The team included representatives from the National Bureau of Standards

(NBS), U.S. Geological Survey (USGS), Bureau of Reclamation and Corps of

Engineers. They arrived in Romania on March 14, 1977. The NBS and USGS

members spent six days in-country and the Bureau of Reclamation and Corps

members, eleven days.

During their visit, team members worked directly with Romanian

scientists and engineers in assessing the damage caused by the earthquake.

They also developed recommendations for technical assistance related

to repair and strengthening of damaged structures, strong motion instrumentation, and exchange of scientific and technical data relating to earthquakes for inclusion as part of a U.S. government assistance program for

Romania.

This report presents observations on the behavior of buildings by

team members from the National Bureau of Standards. The purpose is to

document the performance of buildings designed to resist earthquakes as
well as those which had not been so designed. This information should

be of interest to practicing professionals and researchers. Since this

is the first time AID has sent a team of this particular type into a disaster area to provide on-site technical assistance, the report can also

serve to illustrate the useful technical data which can be obtained from

similar missions in the future.

iv
TABLE OF CONTENTS

Page

Preface iii

Abstract vi

1. INTRODUCTION 1

1.1 Earthquake Characteristics 3

2. BACKGROUND 6

2.1 Seismic History 6

2.2 Soil Conditions 9

2.3 Building Systems and Construction Practices. ... 10

2.3.1 Building Profile of Bucharest 10

2.3.2 Reinforced Concrete Frame Buildings .... 11 2.3.3 Reinforced Concrete Shear Wall Buildings. . . 14

2.3.4 Precast Reinforced Concrete Panel Structures. . 15

2.3.5 Other Building Systems ....... 17

3. SURVEY AND ANALYSIS OF EARTHQUAKE DAMAGE 35

3.1 General 35

3.2 Pre-1940 Structures 36

3.3 Post-WWII Structures 47

3.4 Structures in Craiova 62

3.5 Summary of Observations 67

4. BUILDING PRACTICES 129

4.1 General 129

4.2 Introduction 129

4.3 Summary of P. 13-70 Seismic Design Requirements. . . 131

4.4 Summary of Differences Between the P. 13-70 and the

P. 13-63 Seismic Design Requirements 136

4.5 Microzoning of Bucharest 139

4.6 Summary of Seismic Provisions of the 1976 Uniform

Building Code 141

5. RECOMMENDATIONS 145

6. ACKNOWLEDGMENTS 148

7. REFERENCES 150

Appendix A Composition of Survey Team and Summary of Activities . 151

Appendix B Team Contacts in Romania 155

Appendix C Summary of Romanian Earthquakes ...... 156

V
ABSTRACT

Observations are presented of the damage to buildings resulting from

the earthquake of March 4, 1977 in Romania. The report was prepared by

engineers from the National Bureau of Standards who participated as members

of the U.S. government team dispatched to Romania under the auspices of the

Office of Foreign Disaster Assistance, Agency for International Development.

A summary of the team's activities is included. Background data on the

seismic history of Romania, the characteristics of the earthquake and descriptions of damage to specific buildings are also included. The types of

building construction and the history of the development of seismic design

requirements for buildings in Romania are discussed. Recommendations are

presented for needed building research based on the observations.

Keywords: Buildings; building codes; earthquakes; natural disasters;

Romania; structural engineering.

vi
1. INTRODUCTION

On Friday, March 4, 1977 at 9:21 P.M. local time a destructive

earthquake of magnitude 7.2 (modified Richter scale) occurred in the

Vrancea region west of Focsani in the southeast corner of the Romanian

Carpathian Mountains approximately 150km northeast of the capital city of

Bucharest (Figure 1.1). The earthquake occurred at a depth of approximately

110km and was felt over a large area. There was considerable damage in

Bucharest (pop. approximately 2 million) and the town of Craiova

(pop. 230,000), Zimnicea and Alexandria. Over 30 buildings, among which

were many five and ten story apartment structures, collapsed in Bucharest.

Statistics on casualties and property damage compiled as of the end of

April [12]^ indicate that the earthquake:

0 killed 1,578 people including 1,424 in Bucharest and 154 in

the rest of the country

0 injured 11,221 including 7,598 in Bucharest and 3,723 in the

rest of the country

0 destroyed or seriously damaged 33,000 housing units in high-rise

apartment flats and conventional type dwellings (35,000 families,

more than 200,000 persons homeless)

0 caused lesser damage to 182,000 other dwellings

0 destroyed 374 kindergartens, nurseries, primary and secondary

schools and badly damaged 1,992 others

0 destroyed six university buildings and damaged 60 others

0 destroyed one orphanage and damaged 15 others

Figures in brackets indicate literature references at the end of the report

1
0 destroyed 11 hospitals and damaged 228 other hospitals and

220 polyclinics (health care centers)

0 destroyed or damaged almost 400 cultural institutions such as

theaters and museums

0 damaged 763 factories

0 directly affected over 200,000 people

This report summarizes the field investigations conducted by the

National Bureau of Standards members of the U.S. technical team dispatched

to Romania by the Agency for International Development. A summary of

activities for the entire team and a list of individuals contacted while

in Romania are included in the appendices.

The NBS investigations were confined to Bucharest and the city of

Craiova. Their purpose was to assess the performance of buildings and the

types of damage which occurred. Background data on the seismic history

of Romania, the types of building construction and comparisons between

j U.S. and Romanian seismic design practice are also included in this report.!
1.1 Earthquake Characteristics

The earthquake occurred on Friday evening March 4, 1977 at 9:21 P.M.

local time (12:21:54.3 GMT). The location of the epicenter was 45.84N,

26.73E about 150km northeast of Bucharest (Figure 1.1). The focal depth was

about 110km. About 250 aftershocks had been recorded in a week to ten

days following the main shock. Most had a magnitude below 4; the largest

was magnitude 4.5. Information from Dr. Karl Fuchs, a German seismologist

from Karlsruhe, indicated the epicenters for these aftershocks were moving

southward and occurring at depths of about 50km based on data obtained from

his instruments installed in the epicentral region.

One strong motion record was obtained from an instrument installed at

the Building Research Institute (INCERC) in Bucharest. The Building Research

Institute is located in the eastern part of the city (Boulevard Pantelimon -

Figure 2.2). The Japanese SMAC-B accel erograph (natural frequency-10 Hz,

damping-100% critical) was located in the basement of a one-story reinforced

concrete building. The instrument and installation were inspected by Chris

Rojahn from the U.S. Geological Survey who indicated it had been properly

installed and maintained. A copy of the record is shown in Figure 1.2. A peak

acceleration of 0.2g in the north-south direction occurred about 18 seconds

into the record. The peak accelerations in the east-west and vertical

directions were 0.16g and 0.12g, respectively. The record, unlike most

obtained from other destructive earthquakes, is characterized by a single

strong pulse with a period of about 1.4 seconds. The pulse was recorded

in the north-south and east-west components but not the vertical component

of motion. In view of the relatively long period of the pulse, one would

expect that this earthquake motion would be more severe for flexible, low

frequency structures than for stiffer, high frequency ones.

3
f\!It 4

2. BACKGROUND

2.1 Seismic History

The earthquake of March 4 occurred in a region characterized by

j a long history of damaging earthquakes dating from Roman times. Among !

the strongest earthquakes mentioned in historical records, Ref. 1 lists I

the 1445 earthquake, the shock of which was felt as far as Moscow; the

1472 earthquake which destroyed the Neamtu (Moldavia) Monastery Church;

i the 1683 earthquake which caused the collapse of the Suceava (Moldavia)

| fortress towers; the 1738 earthquake which damaged the Palace in Bucharest;

| the 1802 earthquake which caused the collapse of the Coltea tower in I

Bucharest (located in the present center of the town). Ref. 3 mentions

'

the occurrence in 1832 of what has been referred to as "the great earth- \

quake". Data obtained from the Environmental Data Service of the National

| Oceanic and Atmospheric Administration indicate that 172 recorded earthquakes occurred in Romania between 1908 and February 1976 (Appendix C). |

Over 70 percent of these occurred in the area between 45-46 degrees North lati-i

I tude and 26-27 degrees East longitude in the Vrancea mountain region where th^

March 4 earthquake occurred. In contrast to most damaging earthquakes in the }

I United States which occur at shallow depths, i.e., less than about 30km

(18 miles), most damaging Romanian earthquakes occur at much greater depths,

j

i.e., 100-150km (60-90 miles). The data in Appendix C [2] illustrate the

latter trend. \

I Observations of the historical record by the U.S. Geological Survey

[ suggested the possibility that large deep Romanian earthquakes may occur f

I'

j in pairs. This tendency was displayed in 1912, 1940 and 1945 when large | earthquakes occurred with few if any aftershocks as indicated in the

^ following table:

6 :
YEAR DATE MAG DEPTH COMMENTS

1908 Oct 6 6.8 150 No significant ]_/ aftershocks

1912

1912

May 25

May 25

6.0

6.3

100

100

One or two ^ianifirant aftpr<;hork<s

One or two significant aftershocks

1934 Mar 29 6.3 150 No significant aftershocks

1940

1940

Oct 22

Nov 10

6.5

7.4

150

150

One sianifirant aftpr^^hnrk ^Nov 8^

Many significant aftershocks

1945

1945

Sept 7 Dec 96.5

6.0

100

100

One sianifirant aftp^"^h(^^k f Spot 14)

No significant aftershocks

1977 Mar 4 7.2 100 No significant aftershocks

V Magnitude greater than 4.5

An earthquake of magnitude 6.5 occurred on October 22, 1940. No significant

aftershocks followed until one of magnitude 5.5 on November 8, followed

by the severe earthquake of magnitude 7.4 on November 10. Similarly in 1945,

the magnitude 6.5 earthquake of September 7 was followed by only one significant aftershock until the magnitude 6.0 earthquake on December 9. Earthquake activity prior to the shock of March 4 included a magnitude 5.5 earthquake on October 1, 1976. No earthquakes were recorded in February 1977.

Based on only three cases, however, it is difficult to conclude there is

a trend for large Romanian earthquakes to occur in pairs.

The November 10, 1940 earthquake occurred at a depth of about 130km in the

same region as the March 4 shock. The felt area for the two shocks was

comparable although in 1940 there was less damage in Bucharest and no damage

in Craiova, a city approximately 175km west of Bucharest. However, in 1940.

there was considerable damage in the epicentral area north of Bucharest. There

were 30 recorded aftershocks with the largest having a magnitude of 5.5.

7
Damage to buildings in the 1940 earthquake is summarized in

a report by Niculescu [3] from which the following information is excerpted.

The earthquake of November 10 was reported as intensity 9 (Mercal 1 i-Cancani-Sieber

scale) in Bucharest and strong ground shaking lasted 42 seconds. No instrumental

readings were obtained. The shock of October 22 was of shorter duration and

of intensity 7 in Bucharest. The primary direction of motion in Bucharest

was east-west.

Many roofs, chimneys and walls of buildings were damaged. Apparently

very few roofs collapsed but many were displaced laterally as much as

20cm. No observations of torsional motions of buildings were reported.

Gable walls supported on columns displaced up to 18cm. Vertical and

horizontal cracks and evidence of torsion were observed in chimneys. More i

chimney damage was observed on buildings with high pitched roofs. This

may have been due to the fact that chimneys on buildings of this type

j were higher and consequently more flexible (with longer natural periods).

! There was some damage to buildings as a result of foundation settlement. Dif- I

I ferences in damage between adjacent buildings was attributed to the vari- |

I ation of soil conditions throughout the city. I

i The most significant building collapse in the 1940 earthquake was '

the Carlton building, a 47m high, 11 story reinforced concrete frame

structure, in which 130 lives were lost. A fire in the building followed

the collapse. A commission of experts which investigated the failure ,

found design and construction errors in that many of the beams required

r for wind bracing were missing and less concrete and steel were used than | required by the design specifications. The commission felt that similar !

design and construction errors were present in almost all apartment '

8
buildings built in the same manner in Bucharest.

2.2 Soil Conditions

Bucharest is located on a plane inclined slightly in a north-south

direction as shown in Figure 2.1b. Two small rivers, the Dimbovita in the

southern portion and the Colentina in the northern, traverse the city

from northwest to southeast, the latter interconnecting a series of lakes

within the city as shown in Figure 2.1a. The Dimbovita river bed consists

of alluvial deposits of fine sands with pockets of organic matter. Soil

immediately adjacent to the river is loess and soft clay with an average

depth of 5m with local deposits as deep as 9m. The soil profile in Figure 2.1b

shows the general area is underlain by layers of gravel, clay, and sand. The

average thickness of the sand layer underlying the whole area in Figure 2.1b

is about 15m and the silty clayey sand layer about 60m. Allowable bearing

2 pressures for design vary from 100 - 150 kN/m in the vicinity of the

2 Dimbovita River to 200 - 300 kN/m in higher regions of the plane. The

level of the ground water table varies from about 2m in the vicinity of the

Dimbovita River to 10 - 15m (Figure 2.1a).

9
2.3 Building Systems and Construction Practices

2.3.1 Building Profile of Bucharest

Both in population and area, Bucharest is the largest city in

Romania, with a metropolitan area of about 400km . The Dimbovita and

Colentina rivers which run through the city on parallel courses are shown

in Figure 2.2. The principal thoroughfares converge toward the center of

the city, where they frequently merge and intersect other streets in oblique

patterns, creating a gridwork of polygonal blocks having the irregular configurations illustrated in Figures 2.2 and 2.3.

Most of the structures within a 3km radius of the center of Bucharest

were built before 1940. Among these are a number of historic monuments and

churches (Figures 2.4 and 2.5), massive educational, administrative and

cultural facilities with ornate features reminiscent of earlier architectural

styles (Figures 2.6 and 2.7), and small residential buildings (5 stories or

less) consisting of unreinforced masonry load-bearing walls with, in most

cases, concrete or wood floors. In general, however, the building profile

of central Bucharest is dominated by multistory concrete frame structures

built before 1940 (Figures 2.8 and 2.9), none of which were designed for

earthquake loads. In the aftermath of the destructive earthquake in

November 10, 1940, rudimentary earthquake design provisions, patterned after

the Italian code, were introduced for use on a voluntary basis. Mandatory

seismic design regulations went into effect in 1957, followed by later

versions in 1963 and 1970.

10
It has been noted that during World War II (1939-1945), there was virtually no construction activity in Bucharest. When the city resumed

its outward growth after the war, fundamental transformations began to occur

in building construction. In multistory residential buildings, most notable

was the trend towards greater utilization of precast structural and nonstructural elements, and increased use of framing plans having rectangular,

symmetric configurations (Figures 2.10 and 2.11). Currently, precast panel

systems together with cast- in-pl ace reinforced concrete shear wall systems

constitute about 80 percent of new building construction in Bucharest. The

other systems are mainly buildings of load-bearing masonry construction,

complete moment-resisting concrete frames and buildings that fall under the

category of special structures.

2.3.2 Reinforced Concrete Frame Buildings

Within a 30-year span prior to 1940, a large number of concrete frame

structures were erected in Bucharest*. They are typically 8 to 12 stories

high. The first story is generally higher than the rest and is almost void

of walls to accommodate stores and other non-residential facilities. In the

upper stories, masonry infill walls and partitions are used liberally to

provide enclosure for apartment or office space, and to function as lateral

bracing against wind action. As a result, the structure is characterized by

laterally stiff upper stories resting on relatively flexible columns at the

*According to Beles and Ifrim [11, reinforced concrete as a load-resistant

material for tall buildings was introduced in Bucharest after 1910.

11
ground level. Because they are commonly built adjacent to each other and

more or less conform to the irregular patterns of the city blocks, the end

and corner units tend to be particularly non-uniform in layout. A good

illustration is provided by the framing plan of the eight-story building

shown in Figure 2.12, which is reproduced from the paper by Niculescu [31.

The paper presents the author's observations of building damage caused

by the earthquake in November 1940. It cites major shortcomings in building

design and construction practices in the years prior to 1940 among factors tha

contributed to the inadequate seismic performance of the reinforced concrete

frames in general. In view of the similarities in the response of these

buildings in both the November 1940 and March 1977 earthquakes, it is of

interest to cite the following observations made in that article with regard

to building practices prior to 1940:

Theve existed no huitding inspeotion at the time. Each owner was responsible for his building and could be prosecuted only in case of catastrophe or damage. Only certain prescriptions specified

by the authorities had to be satisfied. The plans had to be drawn

by an architect with a degree. Even though,^ in general, reinforced

concrete design was based on German prescriptions^ they could be

altered according to the wishes of the architect or the user or even

the contractor eager to build as inexpensively as possible.

According to German prescriptions, sufficiently stiff buildings

did not need to be analyzed for wind loads. Some stiffening guidelines were provided together with recommendations to the effect that

in cases of doubt^ the extent of stiffening should be agreed upon with

the inspection authorities. In Bucharest^, a reinforced concrete frame

I

12
was assumed to he suffioiently stiff even in the absence of

stiffening walls so that the stvuctva?es weve not analyzed for

horizontal loads. In addition, the German speoifiaations did

not require analysis of conarete frames in aoaordance with

established frame theory, even when the building was seven stories

or higher. Consequently, not even the bending moment formulas given

therein were used, nor was it considered necessary to vertically

align the columns in different floors. Columns of height-to-thickness

ratio greater than 15 were designed for axial compression only.

Because it was common practice to divide the residences of di^fferent

floors in various ways, the columns had to be so arranged that they

could not be connected directly to the beams. In fact, there were columns that were aligned through all upper floors and rested only

on a girder at the lower floor. On the other hand, the width of

the beams was kept within 14cm so that they would be concealed in

the rooms. It is easy to visualize what the stiffness of such a building will be with respect to horizontal loads.

The earthquake revealed many erroneous practices. For examtple, a oolvmm

in one building had been destroyed at the base. It was found that

ties were missing over a height of 60cm. Furthermore, the vertical bars were connected by simply overlapping the hooks with no additional overlap

It was noted here that structural drawings provided no information on the

ties so that their relative positioning was left to the whim of the con- struction worker.

It also appeared that in certain cases vibrations had caused a pulverizing (grinding) effect on the concrete. In the case of a column that

had been perforated by a layman in order to accommodate a heating pipe,

the concrete was found to have only the resistance of lime mortar. The

destruction of the concrete was probably caused by repetitive stress.

In one case, concrete strength was found to be 65 kg/cm2 (6.4 MN/m2).

In the case of the Carlton building, a court-appointed commission cited

design and construction errors of the type found in almost all Bucharest

apartment buildings, notably, inadequate wind bracing and deficiencies

in the quality of materials used. As to the causes that may have con- tributed to the collapse, the commission noted the unfavorable position

of the 47m high comer tower with respect to the direction of the earthquake motion, possible amplification of earthquake effects due to the

proximity of the foundation to the water table, the location of the

building at the end of a row of tall buildings, and the cantelevering

of the first floor theater seats from the columns. According to the

author, resonance may also have occurred.

* In a 1965 paper [l] Beles and Ifrim attributed the collapse to the

failure of a first floor concrete wall column and the imperfect transmission of the loads to the foundation because of a lack of continuity

of columns.

13
2.3.3 Reinforced Concrete Shear Wall Buildings

Cast-in-place concrete shear wall systems commonly used in Bucharest

conform to two basic configurations. The cellular layout shown in Figure 2.10

is normally used for buildings of up to 12 stories high (although occasionally

it has been used for buildings of up to 18 stories high). It is, in fact, a

mixed system combining cast-in-place transverse and longitudinal shear walls

with cast-in-place transverse concrete frames in the intermediate bays at the

ground floor level to provide relatively large uninterrupted spaces needed for

store use. In the upper stories, the transverse beams, exterior walls and

floor slabs are frequently precast. Symmetry is maintained in both transverse

and longitudinal directions.

The box layout shown in Figure 2.11 also has double symmetry. It consists of an orthogonal array of intersecting shear walls dividing the space

into square and rectangular modules for apartment use. The system has been

used for buildings up to five stories high. The nonstructural fascia walls

(not shown) and the floor slabs are precast. This is a total shear wall

system in the sense that no use is made of either cast-in-place or precast

concrete framing elements (beams, columns, frames) in the construction.

Slip forming as well as conventional formwork are utilized in the erection

of both systems.

Design specifications for concrete strength are based on Romanian

standard 7cm cube tests. The concrete strength comm,only used in shear wall I

buildings is about 20 MN/m (grade B200) for- cast-in-place concrete and

2 25 MN/m for the precast slabs which are usually 130mm thick. The steel

used for main reinforcement is usually grade PC52 having an ultimate strength

of 510 MH/r/.
2.3.4 Precast Reinforced Concrete Panel Structures

Since they were first introduced in 1962, industrialized building

systems have outpaced all other forms of construction in Bucharest. Two

well-refined principal schemes (with 3 or 4 variations each) have emerged

for use in high-rise (9 stories or more) and mid-rise (5 stories) building

construction. Buildings above 5 stories are required to have elevators.

Consequently, construction of 6 to 8 story buildings is uncommon because

of the economic factor.

The plan of a high-rise panel building with a doubly symmetric configuration is shown in Figure 2.13. Selected details of vertical and

horizontal joints are displayed in Figures 2.14 and 2.15, respectively.

Structurally, the system appears to be fairly substantial as evidenced by

the following. The use of panels with castellated edges provides for

longitudinal and transverse interlock between joint concrete and prefabricate.

Mechanical coupling at the joints is effected by means of lapped reinforcement

in the form of loops, and two longitudinal steel bars within the loops provide

added bearing area against the concrete core. Additional longitudinal bars

outside the core are used in vertical joints to supplement flexural tension

reinforcement needed for flange action under lateral loads. The longitudinal

bars in the vertical joints are lapped and welded together at horizontal

junctions to achieve vertical continuity as indicated by the section details

in Figure 2.14. It appears that these are the only tension ties in the

"flanges" of the system since, according to the available details, the

vertical panels are not mechanically coupled to the horizontal joints at

their base. Note that all exterior panels are double walls with insulation

15
in between. Materials specifications for the system call for B300 grade

joint concrete (30 MN/m^ standard cube strength) and PC52 grade steel for

main reinforcement.

Figures 2.16 to 2.18 show specific details of a panel system used in

the construction of midrise buildings. In this case, mechanical union in

the joints is achieved by means of splice bars welded to the transverse

reinforcement of adjacent panels. Longitudinal bars, used singly in vertical

joints and in pairs in horizontal joints, provide added bearing area for the

transfer of tension across the connections. The coupling of the floor panels

is somewhat different (Figure 2.17a). The top bars are splice welded while

the bottom bars are bent up 90 degrees and lapped. This particular scheme

gives greater continuity to the floors at the supports than the lapped loop

arrangement used in the high-rise building system. Another basic difference

between the two systems is that the wall panels in the mid-rise building are

mechanically coupled at their base (Figure 2.17b), so that all vertical bars

are rendered continuous across the horizontal joints, as opposed to the case

of the high-rise building in which only the longitudinal bars of vertical

joints are coupled. On the basis of these differences alone, it appears

that the lateral response of the low-rise building should be closer to that

of a monolithic shear wall structure. The materials specifications for

this system are the same as before (PC52 grade steel and B300 concrete).

2 Concrete strength in the panels is about 25 MN/m . In Figure 2.16, alphanumeric notation is used to designate special reinforcement. Prefix P stands

for 3-mm wire mesh. The special lintel reinforcement designated by prefix C

consists of two longitudinal bars (the size of which depends on the seismic

zone) connected by 4-mm cross bars.

16
Prefix C is also used to designate the 4-mm peripheral bars (shown dotted).

The amount of the main reinforcement, designated by numbers, are specified

according to the seismic zone. For instance, the total weight of the steel

used in the double-wall exterior panel shown in Figure 2.16a is 47.2kg and

57.4kg for seismic zones 6 and 7, respectively.

2.3.5 Other Building Systems

Brick or concrete block masonry bearing wall construction is used for

buildings 5 stories or less in height. The lower stories have reinforced

concrete columns (essentially serving the function of pilasters) at corners

and intermediate locations along the walls, and are cast after the walls are

laid. Reinforcement within the walls and positive connections between the

walls and the columns provide the capacity for integral action in out-of-plane

flexure (normal loads) and under lateral loads (membrane forces). This

practice is also followed in the upper stories where reinforcement and ties

become less substantial.

Moment-resistant reinforced concrete multi-story frames with non-structural

masonry walls laid after the frame is cast are rarely used at present. This

type of construction had been used mostly in the mid-to-late fifties for

isolated instances (i.e., one of a kind) in downtown Bucharest, e.g., the

structure on the site of the Carlton building destroyed by the 1940 earthquake.

These buildings are usually 8 to 10 stories high.

A well known example of special buildings is the 25-story Intercontinental Hotel in downtown Bucharest (Figure 2.19). It is a modern reinforced

concrete frame structure. In plan it looks like an equilateral triangle

with truncated vertices and concave circular sides. Another example
is the computer center for the Ministry of Transportations and Telecommunications which collapsed in the March 4, 1977 earthquake (Figure 3.46).

This was a 3-story reinforced concrete building of flat slab construction

in which the floors were supported by 9 columns arranged in a square pattern

(this building is described in greater detail in Section 3.3).

18
I

I (a) Phreatic contour map of Bucharest

(b) Soil profile of Bucharest (Sect. I-I)

Figure 2.1. Hydrogeological map of Bucharest

19
0.5 0 1 0 2 0 KM 1 I I 1 1
21
22
Figure 2.6. Romanian Atheneum on Victoriei Avenue

r r

1

rr F 1

. ii

A o

1

Figure 2.7. Central House of the Army on Victoriei Avenue,

23
24
I
26
Plan of 8-story concrete frame

structure in Bucharest built

before 1940.

27
28
29
30
Cb) Interior Wall Panel

Figure 2.16. Typical panel details for mid-rise precast building.

31
Zx7 cm. p^- 4>1't

PC 5Z L'^8cm

fx 7cm. of. ^/fy

4-x Jem. pt 4> /d

(a) connection of floor panels (b) connection of wall panels

HORIZONTAL JOINT CONNECTION DETAILS

FLOOR PANEL

Figure 2.17. Floor panel and horizontal joint details of mid-rise precast

building system.

32
Figure 2.18. Vertical joint details of mid-rie panel building system.

33
Figure 2.19. The Intercontinental

Hotel in downtown

Bucharest.

34
3. SURVEY AND ANALYSIS OF EARTHQUAKE DAMAGE

3.1 General

This section presents a survey of earthquake damage in the cities of

Bucharest and Craiova, based on field observations by the NBS members

of the U.S. team, supplemented by information acquired from the Romanian

engineers and scientists who worked with the team. The survey focuses on

damage to buildings since there was no evidence of significant overall

damage to the country's infrastructure. Power, water, rail and air service

were restored very quickly after the earthquake. Ports were unaffected.

Out of an estimated total of 33 buildings destroyed in Bucharest, all

but three were reinforced concrete masonry infilled frames that were built

before 1940 and were of the type described in Section 2.3.2. Two post-WW II

structures that collapsed were sections of multi -story apartments built after

1960. The third building was a modern concrete structure which housed the

computer facilities of the Ministry of Transportation.

In the city of Craiova, although many structures sustained moderate to

heavy damage, it was reported that no collapses had occurred. Among heavily

damaged structures examined were the art museum and the city administration

35
headquarters, both of which had historic significance, and load-bearing

masonry apartment buildings. A number of multi -story apartment buildings

examined exhibited minor facade damage mostly confined to the lower stories.

3.2 Pre-1940 Structures

It was learned from INCERC that most of the destroyed or heavily

damaged buildings in Bucharest were located within a three-pronged downtown area roughly identified by the broken lines shown in Figure 3.1. The

left branch of this area extends towards the west along the Dimbovita River,

the central portion runs along Magheru Boulevard north, and the right branch

extends towards the northeast more or less parallel to the Boulevard of the

Republic. The large solid circles within that area designate the approximate locations of 26 damaged building sites, half of which are numbered for

referencing purposes in the text. The rest of the circles designate sites

about whicji no specific information was acquired.

Unless otherwise noted, all of the buildings discussed below are

multistory concrete frames reinforced with plain steel bars and infilled

with unreinforced masonry walls. Buildings examined but not identified

on the map are not assigned numbers in the text. When used, the names of

the buildings are for identifying purposes only and sometimes refer to

nearby landmarks.

36
Buildings 1 through 4 - Group of Devastated Buildings

Figures 3.2 to 3.6 exhibit the remains of four apartment buildings that

were totally destroyed during the earthquake. These photographs were taken

by an INCERC survey team before removal of the debris. It should be noted

that by March 14, the day the U.S. technical team arrived in Bucharest, all

of the rubble from these and most other destroyed building sites had been

completely cleared.

Figure 3.5 exhibits a rare instance of a collapsed building which was an

interior unit. In general, the collapsed structures were either isolated

buildings or were the end or corner units of a block of adjacent buildings.

A plausible explanation of this trend is provided by the fact that the corner

and end units tend to be less symmetric and more irregular in plan and structural configuration than those at the interior. Consequently, torsional

effects, including the likelihood of coupling of the torsional and translational modes, and unfavorable stress distribution under lateral loads, would

tend to be relatively greater in the end and corner units.

There may be still another factor involved. Numerous instances of

pounding damage were witnessed along the joints of adjacent buildings. It is

possible that under certain conditions the two joints flanking an interior

i building unit could constrain and damp the response of the system in such a

manner as to create less unfavorable stress conditions at the lower levels.

The single joint next to an end unit is less effective in providing

\ such confinement nor will it necessarily help restore symmetry or reduce

I

!
torsional effects. This difference provides a possible explanation of

collapses of end units that were triggered by failures at the lower story

levels (Figures 3.7 and 3.8). In addition, the pounding could have been

aggravated by the fact that the end building was higher in certain cases,

than the adjacent building.

A peculiar phenomenon associated with the collapse of the older structures is evidenced by the extensive pulverization of the concrete as

indicated in Figures 3.2 and 3,4. A member of the INCERC team that examined

wrecked structures immediately after the earthquake noted that in many instance

the concrete had disintegrated completely and a haze of dust particles hung

in the air surrounding the sites. This pulverization effect, also noted during

the November 1940 earthquake (see Ref. 3 and Section P.3.2), may possibly

be attributed to the cumulative degradation of concrete through exposure to

cyclic loading during past earthquakes. Well-rounded ends of story-high

concrete columns that had pried loose and fallen to the ground (see, for

instance. Figures 3.3 and 3.6), as opposed to jagged ends normally found

in concrete failures, may be evidence of internal pulverization of concrete in the joints attributable to past extreme events. It should also be

noted that the use of relatively low-strength concrete (as low as grade BlOO

with approximately 10 MN/m cube strength) was prevalent in the construction

of pre-1940 buildings.

Building 5 - Wilson Apartments

A typical example of partial building collapse precipitated by failure in

the lower stories is provided by the photographs in Figures 3.7 and 3.8 taken

38
soon after the earthquake. Referred to as the Wilson Building, this was

a 12-story apartment structure in which failure of the first story columns

caused the corner bays to shear off from adjacent bays and vertically impact

the ground. The collapse of the top story roofs shown in Figure 3.7 was

possibly a follow-up action triggered by this impact.

The framing configuration of this building is not apparent from the

photograph. In Figure 3.8, the two large pillars in the foreground appear

to be reinforced concrete columns, judging from a joint failure at the

(present) fifth floor level. Otherwise, there appears to be no reinforced

concrete exterior columns in the collapsed portion of the building. The

use of two wythes of clay tile units in the construction of exterior walls

was common practice for this type of structure.

Building 6 - Snagov Building

Figures 3.9 and 3.10 show the partial collapse of a three-story

residential building located on Snagov Street. The building appears to be

a massive, stiff structure with thick exterior walls, partitions, and floor

slabs. This is one of the rare instances where a stiff low-rise structure

had collapsed. The large story height, large perforations in the exterior

walls and slender piers between openings were features that may nave

contributed to its demise.

39
Building 7 - Continental Building

Figures 3.11 to 3.13 show different views of a collapsed multi -story

apartment building named after the Continental Bar in the first story. The

building was located on Ghica Street, west of the Boulevard of the Year 1848.

By reference to Figure 3.11, which was taken before removal of the debris,

it appears that the structure was U-shaped in plan, with the end wings

joining other buildings to form a ring around a central courtyard.

Except for a portion of the left wing, this structure was leveled by the

earthquake. It was learned that a 19-year old boy trapped within that section

was saved 11 days after the earthquake. Figure 3.12, taken the same day,

shows the structural configuration of the left wing which was three bays

deep. Note the common use of double and single wythe brick infill walls at

the exterior and interior of the building, respectively. Although not

designed to function structurally, these walls invariably took the brunt

of the earthquake-induced lateral forces before failure.

The neighboring structures of this site, including the church with the

pear-shaped domes (Figure 3.13), showed no indication of visible damage. In .

Figure 3.11, the tall structure in the foreground and to the right, is an !

11 -story building with its center bay braced over the full height by concrete

j diagonals. It also showed no damage other than the loss of lower story filler

| walls that may have been caused by earthquake action or by the force of falling!

I,' debris; in the figure, the first story is concealed behind the rubble.

I

I

\

I 40 I
Building 8 - Dunres Building

Figures 3.14 to 3.17 are different views of the partially collapsed

Dunres building located on Boulevard Balcescu across from the Intercontinental

Hotel. The name refers to the restaurant on the first floor. Figure

3.14, taken before removal of the debris, shows daylight coming through

the upper story windows that might indicate an open yard in the rear. It is

therefore presumed that the building has a V-shaped configuration.

Structurally, the building is characterized by flexible first and

second stories, where stores and offices are located (Figures 3.14 and

3.15) and stiff upper stories with masonry infill walls and partitions

to provide for apartment space. The upper three stories are progressively

setback and therefore, do not conform to the typical floor plan layout

of the stories below (Figures 3.15-3.17). None of these features are

particularly desirable from the standpoint of earthquake-resistant construction.

Building 9 - Lido Building

Figure 3.18 shows an 8-story apartment building with stores in the

ground floor, located at the end of a block behind the Lido gas station. From

Figure 3.19, the building appears to be U-shaped in plan, overlooking an

interior court, and ajoining shorter structures on both sides. Approximately

the left half of the building collapsed to the ground. The rest of the

building was severely damaged, probably beyond repair. In the standing

portion, the first story exterior columns had failed at the top (Figure 3.18),

while those at the interior exhibited shear failure at the base (Figures 3.20

and 3.21).

41
This building and the one on the left may have caused mutual damage.

In Figure 3.19, it appears that the top story corbel of the building on

the left had pounded against the 7th story column of the Lido building,

causing it to fail at the base. In way of retribution, the collapsing

roof of the Lido building had taken along portions of the roof and masonry

wall of the adjacent building (see Figure 3.18 which was taken before

clearing of the wreckage).

The failure of an interior column (Figure 3.20) exposed four vertical

bars, approximately 20mm in diameter, and a single tie, approximately

6mm in diameter, spaced from the base a distance equal to the depth of

the column. Four hooked footing dowels projected into the base of the

column. The column that failed in shear (Figure 3.21), did not appear to

have any ties within the height of the spalled concrete which was twice

the depth of the column. All bars were plain.

Building 10 - Casata Building

Figures 3.22 to 3.26 show the partial collapse of a 10-story building

which is the end unit of a block of buildings along the east side of

Boulevard Magheru. General views of the building before and after removal

of the debris are shown in Figures 3.22 and 3.23, respectively. The wreckage

in Figure 3.22 indicates extensive pulverization of the concrete, which was

observed at other sites as well.

42
In Figure 3.23 it is noted that the 9th and 10th stories of this

building, both of which are set back, have much longer transverse spans

than the stories below. It appears that the setback wall of the 10th

story is supported only by the 9th story roof slab. Figure 3.24 shows

pounding damage observed between this and the next buildings. Note the

slight tilt of this building to the right. Pounding damage had also

occurred between other buildings in this row (Figure 3.25).

Figure 3.26 shows shear failure observed in an interior first story

column. A total of six vertical bars were used in the column, three in

each face, and approximately 16mm in diameter. The single ties were

approximately 6mm in diameter and were bent only around the corner bars.

In general, concrete cover was insufficient and at certain locations nonexistent. Note, for instance, that on the unspalled top surface of the

column, ties as well as vertical bars are visible with one of the ties

inclined 15 degrees with respect to the horizontal.

Building 11 - Jurist Building

Figure 3.27 is a scene of downtown Bucharest viewed from Piata

Romana towards Boulevard Magheru south. Taken in April 1974, this

photograph shows on the right the 9-story Turist building which was

heavily damaged during the March 4, 1977 earthquake. The Casata building,

which can also be seen, is the last unit of the left block in the

background. This photograph shows a restaurant on the first floor of

the Turist building which also uses the sidewalk as part of its dining

area.

43
A partial view of this building taken after the earthquake

(Figure 3.28) exhibits substantial structural and non-structural damage

in the lower stories. Fallen plaster on the sidewalk, the detached

soffit of the canopy above it (Figure 3.29), and the ruptured facing

of the second story wall on the east side, which had to be propped

to prevent collapse, are instances of potential hazards to pedestrians

(sidewalk users, shoppers, cafe patrons, etc.) associated with the

collapse of non-structural exterior elements that can occur even

when the building itself survives the earthquake. Falling masonry

units resulting from premature failures of inadequately bonded exterior

walls and piers are another potential source of hazard to the pedestrians.

A case in point is the type of masonry construction illustrated

in Figure 3.31 which shows a damaged pier between the second story

balconies. The exposed masonry beneath the fallen plaster is characterized

by poorly bonded units (no head joint mortar used) having different

sizes and shapes.

The worst apparent structural damage occurred at the relatively

flexible first story level within the end bay area as evidenced

by the extensive amount of timber shoring and bracing placed around

the periphery of the building both inside and outside (Figure 3.30).

Loss of vertical support within this area had occured as a result

of column failures such as shown in Figure 3.32. Although the
spacing of the ties (approximately 6mm in diameter) appeared adequate,

they did not prevent buckling of the face bars, probably because

they were bent around the corner bars only. The proximity of the

ties to the column surface was noted here as in other places.

Several heavy timber logs were placed next to the column to shore

up the floor above this location. Metal bars attached to the logs,

timber cross-braces and horizontal back- to-back steel channels are

probably used to brace the auxiliary support system against forces

of possible aftershocks. Elsewhere (Figure 3.33), timber posts were

used to shore the damaged floor slab in the story above. The brick

filler wall at this location appeared to have stopped short of the

ceil ing.

Metal import Building

Figures 3.34 and 3.35 show another partially collapsed concrete

structure characterized by setback stories at the top. Approximately a

2-bay by 3-bay corner section was completely demolished while

the rest of the structure was probably damaged beyond repair.

Daylight showing through the back windows of the upper stories

suggests the possiblity of an open courtyard in the rear. If this

were the case, the building would have an L-shaped configuration

which is not particularly conducive to earthquake-resistant

construction.

45
It appears that some of the masonry walls in this building

served a load-bearing function. For instace, Figure 3.35

indicates that the collapsed stairs and landing were entirely

supported by multiple wythe masonry walls outside and inside the

building since concrete framing elements are conspicuously absent

in this region. Elsewhere, the interior masonry walls in the

upper stories (the plastered walls in the plane of Figure 3.34) are

at least partially supporting the bearing loads transmitted by

the setback walls above. Also note that in the first interior

bay successive stories are partitioned differently.

Mercerie Building

The heavily damaged exterior of this building (Figures 3.36 and 3.37)

made it appear as though it was on the verge of collapse. The

characteristic diagonal X cracks in the lower story piers indicated

the structure had experienced cyclic load reversals. As was usually the

case in other buildings, the most severe structural damage had occured

within the relatively flexible first story where substantial shoring

had to be installed to prevent further distress.

A6
Building 12 - The Ambassador Hotel

The rear view of the Ambassador Hotel shown in Figure 3.38 provides

a typical demonstration of the type of relatively moderate but widespread

damage found in pre-1940 infilled structures in downtown Bucharest. The

stiff masonry walls, initially attracting most of the lateral forces, were

among the first victims of the shock. Particularly susceptible were the

lower story walls. This stems from the fact that masonry filler walls were

not specifically designed to provide either gravity or lateral load resistance and therefore had the same thickness throughout the building.

Building 13 - The Post Office Building

The Post Office Building shown in Figure 3.39 is one of the very rare

instances where steel frame structures are used in building construction

(reportedly only two or three steel structures are found in Bucharest).

The architecture of this building is reminiscent of steel structures built

in the U.S. in the 1930' s. It was indicated that there was no visible

damage to the main structure. Non-structural damage was relatively minor

and was mostly confined to cracking and spalling of brittle facade elements

adjacent to lower story openings.

3.3 Post WWII Structures

As noted earlier, only three post-WVllI structures collapsed in

Bucharest. One of these structures was a multistory residential building

located in the western part of the city. It was reported that a section

of this building had collapsed to the ground and that wreckage had already

47
been removed. The two remaining structures that were surveyed are

buildings 14 and 15 indicated on the map shown in Figure 3.1.

Building 14 - Lizeanu Building

This row of buildings stretches along the north side of Stefan Cel Mare

Avenue directly east of Lizeanu Street. Approximately the three end bays

nearest Lizeanu Street fell to the ground and assumed a slightly tilted

posture after the collapse of the first story columns. Reportedly, the

building was further tilted in an initial attempt by the demolition crew

to overturn it. Subsequently, wrecking operations were carried out from

the top down so that at the time it was inspected, all the stories above

the fourth (counting the collapsed first story) had been already removed

(see Figure 3.40).

It was learned that before the earthquake, this section of the building

was in the process of being underpinned to rectify a foundation problem

encountered earlier. Therefore, it is conceivable that one of the main

reasons, if not the only reason, for the collapse may be attributed to the

presence of this temporary remedial condition at the time the earthquake

struck.

Figures 3.40 through 3.45 present several photographs of the

building taken from different angles at the time of the visit, except for

the rear corner view shown in Figure 3.41, which was taken by an INCERC crew

48
soon after the earthquake, before demolition work had begun. It was

reported that the building is a concrete frame structure with shear walls

in the upper stories. The presence of a concrete frame may be ascertained

from Figures 3.42 and 3.43 and also from the detached reinforced concrete

column on the ground shown in Figure 3.41. Because of the finish, it is

not possible to establish the composition of the transverse walls shown

in Figure 3.40. However, Figures 3.41 to 3.43 indicate that the exterior

longitudinal walls in the back of the building are unreinforced masonry

filler walls.

Figure 3.44 shows structural damage in the first story columns in

the back of the standing portion of the building and the timber shoring

used to prop other damaged sections. There was no other major visible

damage to the exterior of the rest of the building. Figure 3.45 shows

the front view of the building facing Stefan Cel Mare Avenue. Note the extent

of del ami nation of concrete cover underneath the upper story floor slabs

and the concrete stairs shown in Figures 3.43 and 3.45.

Building 15 - Computer Center

The collapse of the building that housed the computer facilities of

the Ministry of Transportation and Telecommunications was the most severe

single incident in terms of its impact on the Romanian economy. As a result,

400 people were put out of work and millions of dollars worth of materials

were destroyed, including computer hardware and software which are not

readily replaceable.

49
A northeast view of the center before the earthquake is shown in

Figure 3.46. The three-story building in the foreground and the access

tower in the background (better seen in Figure 3.49) were structurally

disjoint from the computer building in the center which collapsed.

Figure 3.47 shows the plan of the building together with a sectional

elevation of an end bay and the configuration of first story columns. The

building was a three-story concrete flat slab structure in which 30m square

floor and roof slabs were supported by nine columns spaced 12m on centers in

both directions, and were canti levered 3m beyond the exterior columns. All

second and third story columns were square and prismatic. The first story

columns varied from a square cross-section at the top to the flared configuration shown in Figure 3.47. The columns were approximately 0.5m x

0.5m in cross section, except the flared sections of the first story

columns were larger. All columns were capped with shallow wide capitals

at the top.

The exterior walls consisted of precast concrete sections hung from

the peripheral edges of, and anchored to, the slabs at each story level.

They stopped short of the floor below, as indicated in the same Figure.

The floor slabs were approximately 0.5m thick and had square cellular

hollow cores so that a longitudinal repetitive strip in either orthogonal

direction had the sectional configuration of a wide flange beam with equally

spaced web stiffeners on both sides. The ruptured slab shown in Figure 3.52

| further illustrates the type of construction used. The specified material

2 2 i' strengths were 30 MN/m (grade B300) for the concrete and 510 MN/m for

j the reinforcement bars. There were no shear walls in this structure.

50
Figures 3.48 to 3.55 provide a description of the situation

after the earthquake. Figures 3.48 and 3.49 are views of the north side

of the computer building after the collapse. Note the tilted and detached

walkway slabs between this building and the access tower. The latter

did not exhibit any visible signs of damage. Except for broken window

panes and some damaged interior partitions, the 3-story structure west

of the computer building was likewise undamaged. Figure 3.50 is a partial

view of the south side of the building after the collapse. The hung

exterior walls which did not originally extend to the floor below, now

do. These walls may have been instrumental in keeping the structure

from being totally levelled to the ground.

To the extent that could be established, nearly all the columns in

the building had failed. In most cases the failures had occurred at the

tops of the column just below the capital. Figures 3.55 and 3.51 exhibit

the failures of first and second story columns, respectively, in this manner.

Within the main computer room at the second story level, one column had

ruptured at midheight, as indicated in Figure 3.54. The exterior second

story column shown in Figure 3.53 appears to have failed in flexure after

loss of support elsewhere (note the rotation at the top of this column

conforming to the tilt of the sagging floor slab above).

At the time of the visit to the site, it was learned that investigations

into the collapse of the computer building were underway but that as yet

no definite conclusions had been reached. With regard to the failure

sequence, it was mentioned that according to one lay person who happened

51
to witness the incident, the building collapsed progressively from the

roof downwards. The reliability of such secondary sources of information,

is, of course, unknown.

Based on field inspection and supplementary information acquired at

the site, certain conditions that may have been factors contributing to

the collapse are cited as suggestions for further verification by the

Romanian investigators. It is noted, for instance, that the computer

equipment was installed on raised floors, as is commonly done to simplify

wiring. This brings out the possibility that a premature failure of the

raised floor may introduce a live load dynamic amplification factor

(as a result of the impact of the computer equipment falling on the concrete

floor) not normally considered in design. Figure 3.53 provides evidence

that the raised floor had failed (although not necessarily prematurely).

In Figure 3.52, it appears that the central processor had punctured the

second and first story floor slabs and ended up on the basement floor.

Another deficiency noted by reference to the failures shown in Figures

3.54 and 3.55 is the absence of substantial column ties needed to resist

the shear forces due to transverse loads and torsional effects. The

fact that most columns in the building failed at the top is significant

in that respect. It may be that the building was simply not designed for

the seismic intensity it actually experienced or that the design provisions

for ties were inadequate. In either case, the problem is probably related

to deficiencies in the existing codes.

52
A third possibility is that the fate of the entire building appeared

to be dependent upon the structural integrity of a single column. Stated

differently, there seemed to be no alternate paths of load transfer to

the foundation, if, for some reason, one of the columns were to be removed.

Mechanisms for the containment of localized failures, or built-in redundances

to provide for alternate means of load transfer, if duly recognized by the

codes, are design concepts that would reduce the likelihood of progressive

collapse under the action of extreme events.

Building 16 - Concrete Shear Wall Building

Among relatively recent structures examined were a number of buildings

located close to INCERC (Figure 2.2) on Boulevard Pantelimon in the eastern

section of the city. The three structures that were surveyed in greater detail

than others were built well after 1970 and therefore were designed according to

the latest seismic provisions issued in 1970 (see condensed version presented in section 4.3). These buildings are identified by numbers 16 to 18

on the general map of Bucharest shown in Figure 2.2.

The first building inspected was an 11 -story concrete shear wall

structure having the cellular layout described in section 2.3.3. It was

located at the end of a row of multistory apartment houses and had a layout

almost identical to that shown in Figure 2.13 (the plans were examined prior

to the visit). The front of the building, a partial view of which is shown

in Figure 3.56, gave no visible indication of damage. The end view of the

building likewise revealed no damage except for some minor cracking in the

lower story shear wall couplers (Figure 3.58). It should be noted that in

53
buildings which were not seriously affected by the earthquake, and this was

one of them, a visual assessment of external structural damage was often

rendered difficult by the presence of facing walls used for insulation

purposes. A case in point is the delamination of the first story facing wall

shown in Figure 3.59 which, without close inspection, could be mistakenly

associated with structural damage.

At the first story level, the structural system in the transverse

direction consisted of three shear walls and six intermediate frames as

indicated in Figure 2.13. Within the first story restaurant, the only

structural damage noted was the cracking of one of the frame columns shown

in Figure 3.60. Within the second story apartments inspected, considerable

damage was noted in the concrete shear wall lintels above door openings,

particularly those in the transverse direction. Elsewhere, a good deal of

cross-cracking in the plaster of transverse walls (Figure 3.61) had occurred,

an indication of reversed cyclic response. The direction of the transverse

walls approximately coincided with the N-S component of the ground motion

which attained a maximum acceleration of 0.2g according to the strong motion

records obtained from the accelerograph located on INCERC grounds nearby

(see Figure 2.2).

On the whole, the extent of structural damage was moderate and was

mostly confined to the first three stories. Apparently, the building

occupants were not evacuated. One of the proposed repair schemes discussed

with INCERC engineers involved casting of additional concrete shear walls

within the transverse frames of the first three stories.

54
Figure 3.57 shows a 12-story building under construction located on

Boulevard Pantelimon right across from the shear wall structure. This

photograph was taken mainly to illustrate the generally poor quality

masonry construction frequently observed, even in the most recent

structures. The reason for using brick in the lower stories and concrete

block in the upper stories was not established although it might have been

influenced by availability of materials at the time of construction. Note

the lintel frames over the eighth story window openings. Subsequently,

these are filled with concrete as in the lower stories.

Building 17 - Concrete Frame Structure

One of the buildings examined was an 11 -story concrete frame structure

that was under construction and had not yet been fully occupied. Figure 3.62

shows the building viewed from the side. It was noted that during the earthquake, the frame had pounded against the box- type shear wall structure next

to it and had broken one of its diaphragms.

This was another instance where low quality workmanship and

materials were found in the construction of masonry filler walls, as well

as walls built exterior to the frame (Figures 3.62 and 3.68). Appearance

is not a factor here because the walls are plastered before the structure is

put in service. However, it seems that the structural integrity of the walls

55
IS not a principal concern either. It almost appears as if the only

purpose is to create enclosure by using whatever materials happen to be

at hand and to cut down on the consumption of mortar to the bare

minimum needed to keep the units from falling off during construction.

The ground floor of this building was actually two stories in one,

with a built-in mezzanine accessed from within (Figures 3.63 and 3.69). The

longitudinal bay nearest the street was two stories (about 8m) high as

seen in Figure 3.63 and, therefore, the unsupported length of front exterior

columns in the transverse (approximately N-S) direction was twice that of

columns at other locations. Without shear walls in this area, the lateral

resistance of the first two stories was entirely dependent on continuous

frame action.

Structural damage within this area was generally moderate but quite

widespread. Several of the transverse beams below the third story floor

slab exhibited failures near the supports and had to be shored by metal

pipes at intermediate locations as indicated in Figures 3.69 and 3.70.

The latter shows the single stirrup noted below a section of spalled

concrete approximately equal in length to the height of the beam. The

most extensive damage occurred in one of the long exterior columns. Figures

3.64 and 3.65 show the elaborate steel system used to keep it under lateral

confinement. The concrete had spalled at about 1.5m above the floor

and extended another meter beyond. The column was about 850mm square.

The main reinforcement was about 25mm in diameter. The ties were spaced

56
about 300mm and were approximately 6mm in diameter. The ends of some of

the ties that had opened up appeared to have been bent 90 degress around

the corner bars. Figures 3.66 and 3.67 show two additional columns that

were not damaged as severely. The ties at both locations were about 6mm

in diameter spaced at 100mm on centers. The upper stories of this

building were not examined.

Building 18 - Concrete Frame Structure

The next building examined was similarly a reinforced concrete frame

structure in which the first story elements exhibited a similar but

somewhat less extensive damage pattern. Figures 3.71 and 3.72 show two

transverse beam failures characterized by diagonal cracking at the

column supports. A close-up view of the beam shown in Figure 3.72

revealed two positive bars of unequal size and a single stirrup in the

region of the spalled concrete. The smaller bar (in the background)

appeared to have buckled. At another location, the spalled concrete at

the top of a column (Figure 3.73) exposed a bent corner bar but no ties.

Within the second story, considerable cracking and spall ing of

plaster had occurred, but this was generally not extensive enough to permit

assessment of structural damage, if any. One exception was the cracking

of the stairway at the second story landing shown in Figure 3.76. In

connection with the partition wall within a second story apartment unit

(Figures 3.74 and 3.75), two peculiarities were noted. First, the cracked

plaster was exceedingly thick (about 100mm). Second, the partitions did

not conform with the framing arrangement. The wall in this case was

57
located behind a transverse structural beam and the space in between had

been filled with masonry units overlain with plaster (note its thickness

in Figure 3.75). At the time of inspection, most of the brick units had

pried loose and fallen to the floor.

Figure 3.77 provides a further illustration of the general lack of

emphasis placed on the quality of masonry construction when used in filler

walls, parapets and other non-load bearing applications. Exposed concrete

columns at several locations suggests that there may have been considerable

shedding of masonry units from the walls of this building during the

earthquake. Figure 3.78, which is the rear view of the same building,

shows substantial pounding damage to this structure and the one adjacent

to it, including the partial collapse of several masonry filler walls and

possibly structural damage to a fifth story corner column in the adjacent

building. In the building further to the left (Figure 3.79), many of the

piers that had been already repaired but not plastered over, showed

classical X cracking patterns.

In this general area, several other instances of pounding damage were

witnessed, such as shown in Figures 3.80 and 3.82 to 3.84. The former was

a frame building located next to a shear wall structure which showed no

visible signs of exterior damage (Figure 3.81). The most severe pounding

damage observed had occurred as a result of the collision between a

taller frame building and a shorter structure having adjacent corners.

58
Figures 3.83 and 3.84 are two opposite views of the damage which seemed

to have occurred mostly in the frame structure including the rupture

of a corner column in the story opposite the top of the next building.

Other Recent Structures

A number of apartment buildings of relatively recent construction

were examined in the southern part of the city near Boulevard Magurele.

These buildings are collectively identified by the number 19 on the map

shown in Figure 2.2. The first building was a 5-story precast panel

structure shown in Figures 3.85 and 3.86. No evidence of damage, not

even signs of hairline cracks, was found inside or outside the building.

The second building, shown in Figure 3.87, was a 10-year old cast-inplace concrete shear wall structure in which breakage of window glass

and appearance of hairline cracks near the first story stairway landing

were the only visible signs of damage. This observation was also

corroborated by the superintendent of the building. Because the first story

was used for residential purposes, its stiffness was more compatible with

the rest of the structure than would have been the case had that area

been designed for store usage. Note the superior quality of the exposed

masonry used in the construction of the end wall of the building.

The third building, shown in Figure 3.89, was a 4-year old slip-formed

shear wall structure which was likewise used exclusively for residential

59
purposes. There was no visible damage on the outside of the building.

Inside, there were minor cracks in the lintels above some of the doorways

to the first story apartments. According to one of the tenants, there

was no other damage elsewhere in the building.

The fourth building, shown in Figure 3.90, consisted of two 11-story

rectangular structures interconnected at their corners. It was an 11-year

old slip-formed shear wall building in which the only visible damage was

confined to the first story hallway area where insignificant superficial

cracks were observed in the walls and at the stairway junctions. Inspection

of exposed structural elements within the basement showed them to be free

of cracks.

Figure 3.88 is a view showing some of the other typical layouts used

in multistory apartment construction in this section of the town. Insofar

as could be discerned by cursory visual examination, there were no conspicuous signs of major exterior damage to these structures.

There was also some evidence of physical damage to buildings in

the suburban town of Magurele, 12km due south of the center of Bucharest

(see Figure 2,2). The modern looking 5-story hotel where the members of

the U.S. technical team were stationed was located on the campus of the

National Center for Physics (Figure 3.92). Although this building suffered no

exterior damage, several interior walls at the first-story level exhibited

substantial damage, through-cracks and detachment along horizontal and

60
vertical joints. The upper stories were relatively free of major damage.

Next to the hotel, the 11-story institutional building shown in Figure 3.93

had suffered substantial superficial damage including stripping of plaster

from stiff precast masonry facade panels in the fourth story and from

masonry coupler walls (on the right), and through-cracks in the first story

slab and masonry side wall (not shown). The interior of this building

was not examined.

Among modern buildings in Bucharest, observed mostly in passing, the

National Theater next to the Intercontinental Hotel (Figure 3.91) exhibited

cracking in one of the exterior columns supporting the overhanging roof and

minor spall ing in the tower facade. The Intercontinental Hotel in the same

block (see Figures 2.3 and 2.19) did not appear to have suffered significant

structural damage. However, substantial and costly damage of a non-structural

nature, such as detachment, cracking and relative displacement of interior

partitions, had occurred within the building. In general, flexible buildings

or flexible parts of buildings (i.e., soft first stories) appeared to have

been subjected to motions large enough to cause the type of nonstructural

damage associated with partial loss of functionality or serviceability.

Relatively speaking, such losses were considerably less severe in the case

of stiffer structures.

I

61
3.4 Structures in Craiova

The city of Craiova is located 185km west of Bucharest on the

bank of the river Jiu, a tributary to the Danube 60km to the south.

According to a 1972 estimate, Craiova is the seventh largest city

in Romania. It is located in seismic zone 6 as indicated in Figure 4.1.

Consequently, its buildings were not designed for seismic loads, except

those post-1970 structures which were of exceptional importance (class I

category in Table 4.1) and for which the P. 13-70 provisions were applicable

(section 4.2), were designed using a seismic acceleration coefficient of

k^ = 0.03 (or 3 percent of gravitational acceleration) as indicated in

Table 4.1.

During the brief visit to Craiova, only a few buildings could be

examined. Upon arrival at the city government headquarters (Figure 3.94),

the members of the visiting team were met by the vice mayor of Craiova who

supplied general information about the city. It is 17 centuries old, has

a current population of 230,000, a university with 7 departments and 7,000

students, and manufacturing facilities for chemicals, electrical equipment

and machinery. Total casualty figures were not supplied but it was indicated

that a substantial number of the human casual ities had occurred in the

streets as a result of falling debris.

The city is built on four terraces, rising successively from the

river in the southwest. The second terrace from the river had felt the

worst shock, except in the Craiovitsa section, where the structure of the

soil is different, there was less damage. In general, the buildings in

the rest of the city including industrial plants suffered only minor damage.

62
No major building collapses had occurred in the city. A number of

brick houses and a block of new brick apartment buildings had been damaged.

The most serious damage had occurred in old and historic buildings such as

the city administration headquarters building (Figure 3.95) and the art

museum (Figure 3.99). The former had been damaged in the November 10, 1940

earthquake, but the effect of that earthquake had been much less severe.

In the present earthquake, some of the 1940 cracks that were repaired had

reappeared.

The city government office building (Figure 3.94) where the meeting

was held showed no damage. After the meeting, the first building toured

was the city administration headquarters (Figures 3.95-3.98). Major vertical

cracks had occurred at the top of the brick wall of the central tower as

seen in Figure 3.95. The cracking had developed just below the pyramidal

high pitched roof and had propagated downward on both sides, putting the

structural integrity of the steeple in jeopardy (Figure 3.96). To maintain

stability, two Vierendeel type steel joists were installed horizontally on

the near face and were anchored by cables to the rear portion of the tower

as indicated in Figures 3.95 and 3.96. There was also evidence of roof

damage due to collapse of the cupolas, as shown in Figure 3.95.

Within the building, the structure of the ceiling consisted of a series

of spherical and cylindrical brick vaults supported by massive brick

columns and bearing walls. At one location a portion of the ceiling had

63
collapsed (Figure 3.97). At other locations the ceiling and the archways

were severely cracked and displaced relative to the supports (Figures

3.97 and 3.98). The repair of this building will require the expertise

of professionals specialized in the restoration and preservation of

historical monuments.

The second historical structure examined was the art museum (Figures

3.99-3.103). It was a massive masonry bearing wall building with a

heavy timber floor system. Most of the damage was attributed to the

collapse of the chimneys that had fallen inside and outside of the

building. Figure 3.99 shows the damage caused to the exterior facade

and balcony by a fallen chimney. In one instance, a cupola had fallen

into the building and had damaged the flooring below. Figure 3.100

exhibits the exposed timbers of a floor damaged by falling debris. The

floor joists were approximately 0.3m square, spaced at about 0.6m on

centers. Falling debris had also caused breakage of a decorative skylight

above one of the first story rooms (Figure 3.101). The brick walls in the

first story, which were about o.5m to 0.7m thick, were not seriously

cracked, although a good deal of decorative plaster had spalled off

both walls and the ceiling.

The attic of the building was accessed by narrow stairs that had

been seriously damaged. Within the attic, the high-pitched timber roof

was supported by a timber framing system laterally stiffened by knee

braces as shown in Figure 3.102. At a few locations splitting of knee

64
braces and frame members were noted. Figure 3.103 shows the splitting

of one of the laterally unbraced brick chimneys projecting beyond the

roof. In general, the extent of damage was such that the building will

be relatively easy to repair without compromising its historical

appearance. On the other hand, retrofitting it for resistance against

future earthquakes will not be as simple. One possibility discussed

with the Romanian engineers involved stiffening of the attic floor to

give it increased diaphragm capability to improve the distribution of

lateral forces to the shear walls below.

The third building examined was a 5-story unreinforced masonry

load-bearing wall system. Tv;o of the wings of the building shown in

Figures 3.104 and 3.105 exhibited cracking of first story piers.

The latter also shows the development of a major vertical crack between

two first story abutting walls at one corner of the building. It appeared

that most of the damage had occurred in the first story where many of the

exterior piers exhibited severe diagonal cross cracking as shown in

Figure 3.106. By reference to this figure, two distinct modes of failure

can be identified. In each of the four different instances shown, the

wide pier had attained its collapse limit state, characterized by through

tension cracking along the diagonal (s), while the slender pier located

next to it had developed horizontal flexure cracks at the ends (a first

limit state), without appreciably losing its vertical load-bearing capacity.

65
Inside the first story, the solid interior walls were not

as severely damaged (Figure 3.107) but most lintels above openings

had received a good pounding (Figure 3.108). One of the repair

schemes that was being considered for this building was the application of gunite over wire mesh on both sides of the first and second

story walls. The Romanian engineers also expressed interest in

learning more about the structural rehabilitation methods used in

the United States, particularly tuckpointing of masonry and use of

epoxy resins in the repair of concrete and masonry cracks.

Elsewhere in the city, two or three instances of pounding

damage between buildings were noted during the survey such as shown

in Figure 3.109. There were also a number of buildings with partly

missing roofs and fallen chimneys. Inspection of 10-story reinforced

concrete shear wall buildings, some of which were reportedly erected

quite recently using the slip-form method, revealed minor non-structural

damage, mainly in the first story exterior insulation walls as seen in

Figure 3.110.

66
3.5 Summary of Observations

The devastating effect of the March 4 Romanian earthquake is

evidenced by the casualty figures and property losses that have been

reported in Section 1. The full impact of the earthquake in terms of

human suffering, disruption of productive activities and expenditures in

relief and rehabilitation is not readily quantifiable but probably will

magnify the cited disaster statistics manyfold.

The fact that most of the casualties occurred in Bucharest and

as a result of the collapse of pre-1940 apartment buildings underscores the

immediate necessity to address the problem existing in similar structures

which, even though survived this earthquake, may well have been rendered structurally inadequate to resist forces of future earthquakes of

even lesser intensity than experienced on March 4. Considered collectively,

these buildings shared many of the deficiencies noted below:

2

1. Low concrete strength, viz., lOMN/m or less.

2. Cumulative damage resulting from past extreme events such as

the 1940 and 1977 earthquakes and World War II.

3. Inadequacies in ties and stirrups including excessive spacing

and improper anchorage.

4. Insufficient reinforcement cover.

5. Flexible first story supporting stiff upper stories.

I 6. No lateral bracing other than non-structural masonry walls

having low membrane capacity and not specifically designed to

resist lateral forces.

\

I 67
7. Irregular layout and structural discontinuities.

8. Progressive setbacks of upper stories often without auxiliary

supports or bracing below.

9. Structural and non-structural modifications during service often

carried out without particular attention being given to their

effect on the overall integrity of the system.

10. Low bond between concrete and steel reinforcement attributable

to use of plain bars and insufficient splices and anchorages.

11. Proximity of buildings giving rise to distinct possibility of

pounding damage in an earthquake.

12. Improperly bonded exterior masonry walls and the potential

hazard to pedestrians arising from their premature failure.

Particularly disturbing was the extensive disintegration of concrete

that had occurred at the destroyed pre-1940 building sites as noted by

independent observations following both the present and November 10, 1940

earthquakes. This phenomenon may be associated with low specified concrete

strength or possibly with cumulative damage attributable to past extreme

events as noted in the first two items above. A third possibility is that

less cement may have been used in the concrete than called for by design.

In this respect, it is interesting to note that the commission investigating

the collapse of the Carlton building after the 1940 earthquake had found the

concrete and steel used in its construction were less than required by the

design specifications (see Section 2.1 and Ref. 3).

68
It is hoped that investigations will be undertaken to determine the

extent of degradation of in-situ concrete in the pre-1940 buildings, and

whether or not it will be economically feasible to retrofit (rather than

replace) any of these structures in a manner that would reduce the seismic

risk involved to a level that would be locally acceptable. This would

require sampling and testing of concrete specimens extracted from the

sites to determine their composition and mechanical properties, as well as

definition of a minimum level of acceptable seismic risk as part of the

decision making process.

From the standpoint of structural safety, the performance of postWWII buildings in Bucharest was remarkably good. This is a positive reflection on the seismic design and construction practices introduced in

the 1950's and progressively refined into the comprehensive provisions

currently in force (see Section 4.3). As noted in Section 3.4, of the

three post-WWII building collapses in Bucharest on record, the two that

were examined by the NBS team presented certain unusual circumstances

which may have adversely affected their seismic response.

It appears, however, that the current seismic provisions were somewhat

less effective in mitigating substantial economic losses associated with

structural and non-structural damage of a less serious nature, judging from

the damage statistics compiled in Section 1. Although these figures provide no specifics as to extent and nature of damage in relation to type,

age and location of buildings affected, they include institutional and

public facilities such as hospitals, health care centers, nurseries,

69
kindergartens, university buildings and manufacturing plants, many of

which were probably erected during the post-WWII period when seismic

requirements had gone into effect.

Specifically, the numerous instances of pounding damage of buildings

witnessed both in Bucharest and Craiova suggest the need to reexamine

the rationale behind the building separation requirements currently in

force. In this respect it would be useful to attempt to reconcile the

respective drift and building separation provisions of the P. 13-70

document [6] and the Uniform Building Code [8] which are derived from

fundamentally different principles.

Secondly, potential hazards to pedestrians and dwellers from

falling debris in an earthquake can be reduced by improving the quality

of materials and workmanship used in the construction of masonry walls

for non-structural applications. Examples of exposed masonry construction of superior quality (see Figures 3.90 and 3.93, for instance),

suggest that the skills required to bring about such improvements are

at hand.

A third area deserving attention is the practice with regard to

the use of ties and stirrups in concrete columns and beams, respectively.

There were cases of failures where ties and stirrups appeared to be

I minimal and improperly anchored. In other instances they seemed to be

| quite adequate. The differences could not be altogether explained in !

70
terms of apparent differences in the design loads. The question thus

arises whether there could be discrepancies between the structure as

built and the code recommendations and also whether these recommendations

are adequate, particularly in situations where the lateral resistance

of a building is entirely dependent on continuous frame action.

Fourth, the prospects of survival of buildings in an earthquake

could be improved by incorporating, at the design stage, alternative

mechanisms of load transfer aimed at the containment of local failures,

should a relatively small portion of a building become structurally

impaired. This is particularly important in the design of buildings in

situations where a collapse would be most catastrophic in terms of

human casualties, economic loss, and disruption of services deemed

essential to the post-disaster recovery effort.

It is finally noted that the damage resulting from this earthquake

could provide a basis for assessing the relative merits of various

building systems in resisting earthquake loads. An important question

to be resolved is to determine the engineering implications of the fact

that stiff structures, both precast and cast in place, generally performed better than more flexible types of buildings. It is possible

that resonance may have adversely influenced the response of flexible

structures with fundamental periods in the order of 1 to 1.5s, as

suggested by the characteristics of the only strong motion record

available (Figure 1.2). On the other hand, the magnitude and frequency

« 71
content of this earthquake may have been such that stiffer structures

were not put to test in a manner that would provide sufficient indication about whether they are capable of post-cracking ductile behavior.

It is felt that the opportunity exists for these and other critical

questions to be resolved through a coordinated research effort involving

field investigations and selective testing of scaled buildings and prototype components, coupled with analytical studies of seismic response

using mathematical models of buildings and digitized time-histories of

the available earthquake records.

72
73
Figure 3.2. Cafe Scala apartment

building totally destroyed

by the earthquake.

Figure 3.3. Opposite view of the Cafe

Scala building ruins.

74

Figure 3.6. View of wreckage of the

multistory apartment

building at Boulevard

Hristo Botev No. 10.

Figure 3.7. General view of failure of

Wilson apartment building.

76
Figure 3.8. Close-up of damaged Wilson

bui Iding.

K r 1 I .

Figure 3.9. Partial collapse of threestory residential building

on Snagov Street.

77
Figure 3.10. Close-up view of the collapsed bay of the building

on Snagov Street.

Figure 3.11. General view of the collapse

of the multistory Continental building before

removal of the wreckage.

78
Figure 3.12. View of Continental

building after partial

removal of debris.

Figure 3.13. Standing left wing portion

of Continental building with

Russian church in the

background.

79
Figure 3.15. Southeast view of Dunres building after clearing of debris

80

Figure 3.18. Partial collapse of Lido building.

3.19. Close-up view of Lido building after removal

wreckage.

82
Figure 3.20. Failure of interior first

story column at the base

indicating lateral displacement.

Figure 3.21. Shear failure at the base

of first story interior column.

83
Fiqure 3.22. General view of the collaps

of the end bays of Casata

building

Figure 3.23. Casata building after removal

of debris.

84
Figure 3.24. Damage due to pounding of

the Casata building with

the next structure.

q

Pmnnn %, mm mt^iimm %mmm m^mm

Figure 3.25. Pounding damage to other

structures in the Casata

building block.

85

Figure 3.28. General view of the Turist

building after the earthquake.

Figure 3.29. Close-up view of detached

soffit of the canopy over

the sidewalk.

87
i
Interior view showing

failure of first story

column at the base.

Figure 3.33. Timber logs shoring partially

damaged floor slab of

second story.

89

Figure 3.36. Damage of eight-story

Mercerie building.

Figure 3.37. Another view of Mercerie

building showing configuration of upper story setbacks

91
Figure 3.38. Damage of multistory Ambassador Hotel , rear view.

92
Figure 3.40. End view of partially collapsed Lizeanu building taken

from Lizeanu Street looking

towards east.

Figure 3.41. Rear view of collapsed portion

of Lizeanu building before

removal of debris.

93
94
95
Figure 3.46. Computer center of the Ministry of Transportat-^on and

Telecommunications before the earthquake.

3_

12

12

3~

I I

A

3

3' 12

B

L

12 3

I I

.1 I

B-B

A - A

(plan dimensions in meters)

Figure 3.47. Structural details of the computer building.

96
cn

cu -a • ,— CL) -M -r- ^

=3 n3 M- -Q 3 O CT 2 O) -M

CD +-> ^-

•r- £Z n3 > O) CD U

+-> O)

S- -C

O) O) -M

-M Cl <D

S- E -t-> O O Hcn

Sx: 1— O) -M -1- ^ o cr

s- ^

CU +-> •I- c fo > CL) CD

CJ -M QJ

c/1 S- ^ fO CD +-> CD 4J -C Z3 S- +J CL (D

S- E -M O O 4- S O (T3

CO

97
Figure 3.51. Interior view of second story wreckage.

98
99
Figure 3.54. Failure of second story column located in the air conditioning room.
Figure 3.56. Partial front view of

11-story apartment building

on Boulevard Pantelimon

(Building No. 16).

Figure 3.57. Multistory apartment

building under construction

across from Building 16.

101
102
Figure 3.60. Interior view of first

story restaurant in

Building 16.

Figure 3 . 61

.

Cracking of wall plaster

inside second story apartment Building 16.

103
104 i


Figure 3,68. Exterior masonry walls at the

first story 1 evel

.

Figure 3.69. Metal pipes used in shoring

damaged transverse beams.

107
Figure 3.70. Failure of transverse beam

at the support.

' 1

//

Figure 3.71. Shoring of damaged first

story beam in multistory

concrete frame building.

(Building No. 18)

108
109
Figure 3.75. Detached masonry units

between ceiling and wall.

110
Figure 3.76. Damage within second story

ha1 Iway

.

Figure 3.77. Exterior view of multistory

apartment building.

Ill
I

112
Figure 3.80. General view of superficial

damage in concrete frame

building next to shear wall

building on the left.

/

Figure 3.81. Front view of 10-story shear wall building,

113
114
11

Figure 3.84. Same pounding damage viewed

from the opposite side.

Figure 3.85. Front view of 5-story

large panel building.

115
116
117
4

Figure 3.90. Another ll-story slip-forme

shear wall building.

4

Figure 3.91. National Theater next to

Intercontinental Hotel.

118
Figure 3.92. Five-story hotel on campus

of National Center for Physics

in Magurele.

igure 3.93. Superficial damage of

multistory building on campus of National Center

for Physics.

119
3.95. View of city administration

headquarters building in

Craiova showing damaged

tower and roof.

120
Figure 3.97. Partial collapse of vaulted

ceiling within administration building.

121
122
Figure 3.101. Damage of decorative skylight within the first

story of the museum.

123

125
Figure 3.106. Failure of first-story piers.

126
igure 3.107. Damage of interior

masonry wal 1

.

Figure 3.108. Damage of lintel wall in first story.

127
128
4. BUILDING PRACTICES

4.1 General

Many buildings in Bucharest subjected to the earthquake of March 4

were designed to resist earthquakes. It is therefore of interest to

examine both the behavior of these buildings and the seismic design

requirements with a view to assess the adequacy of the latter.

The material in this chapter is presented for this purpose. A

summary of Romanian seismic design requirements based on an NBS

translation of the original Romanian text, P. 13-70, issued in 1970,

is presented in Section 4.3. The principal differences between these

and the preceding requirements P. 13-63, issued in 1963 [4] are discussed in Section 4.4. Section 4.5 gives a description of the

microzoning of Bucharest which went into effect in 1973. For purposes

of comparison, a brief summary of the main earthquake design provisions

of the 1976 Uniform Building Code is compiled in Section 4.6.

4.2 Introduction

As indicated in Ref. 3, before the November 10, 1940 Romanian earthquake, structures were generally designed for vertical loads only, and

were seldom checked for wind forces. No earthquake loads were considered

in design. The seismic design recommendations introduced in the aftermath

of the 1940 earthquake were based on the provisions of ttie Italian building

code but were not made mandatory.

129
Following a heavy increase in construction activity in the

late 1940' s and especially in the 1950' s, a research effort was undertaken

and used as the basis to develop a draft seismic design standard

in 1957. This is described in some detail in Ref. 5. Building code

requirements representing a modified version of this draft were issued

in 1963 as a legally binding document under the designation P. 13-63 [41.

This document was superseded by the latest edition P. 13-70 issued in

1970 [6]. The fundamental principles of the 1957, 1963 and 1970 documents

are essentially similar, each successive document incorporating a number

of refinements based on the experience gained from practical application

of the provisions, observations reported following major earthquakes, and

research results obtained in Romania and internationally.

130
4.3 Summary of P. 13-70 Seismic Design Requirements [6].

The magnitude of the lateral seismic design loads is given by:

where S|^^ designates the force acting at level k corresponding to the r-th

vibration mode, k^ is a coefficient dependent on the seismic zone and importance of the structure (Table 4.1), 3^ is a coefficient dependent on

foundation soil conditions and natural period T^ (in seconds) of the structure

in the r-th vibration mode, i) is a coefficient dependent on the damping and

ductility characteristic of the structure, n|^^ is a coefficient dependent on

the modal participation factor, and is the sum of all gravity (dead and

live) loads above level k. Live loads associated with the weight of residential building occupants in buildings where large concentrations of people

occur infrequently, or with the weight of moveable installations, equipment,

etc., are multiplied by a reduction factor of 0.8.

131
Table 4.1 - Values of coefficient k

s

Class Description Seismic Zone

I Structures of exceptional _6 7 8 9_

importance^ 0.03 0.05 0.08 0.12

II All structures, except those

of classes I, III & IV - 0.03 0.05 0.08

III One-story structures and other

structures for which losses in case of failure would be moderate - 0.02 0.03 0.05

IV Structures of secondary importance

for which losses in case of failure

would be small - - - 0.03

^More precise definitions of classes I, III, IV are given in Reference 6.

'^Seismic Zone Map for Romania is shown in Figure 4.1.

For certain types of structures (e.g., nuclear installations) special

criteria may be used as required by the appropriate regulatory agencies.

"The coefficient is specified as 0.6 1 3^ = 0.8/T^ ^ 2.0 except that

(a) for structures other than masonry or reinforced concrete, if the foundatio

soil consists of rock or consolidated gravel, 0.48 1 3^, 0.64/T^ <_ 1.6, and

(b) if the soil conditions are unfavorable*, 0.9 1 " 1-2/T^ ± 2.5. These

exceptions are not applicable if the local soil conditions are taken into

account in microzoning maps. In calculating the period T^, the elasticity

of foundation soil is taken into account. As a result, T^ will be greater

and 6^ will be smaller (subject to the lower limitation specified above)

than if T were calculated assuming fixity at the foundation level.

Detailed descriptions of soils for which the specified relationship

applies are given in Reference 6.

132
The specified values of ip are 1.0 for frame structures, 1.2 for

structures with shear walls, 1.3 for structures with bearing walls, 1.8 for

tall, very flexible structures (e.g., antennas, etc.), 2.0 for water tanks

and 1.2 for all other structures.

The coefficient is determined as follows

2 "Jr

'kr =

u, i = l kr —

2 Q . u .

j = l (4.2)

where u^^ is the coordinate at level k of the r-th modal shape.

In addition, it is required that the following relation be satisfied:

n n 2 S.

T > 0.02 2

k=l k=l

(4.3)

In designing structures for which T-j < Is and the height H < 40m,

only the fundamental vibration mode need to be taken into account. If

T"! > Is or H >40m, the first three vibration modes must be taken into

account. In this latter case r3 , N

= r=l (4.4)

where is the force in any given member induced by the loads S|^^ (k=l,

2, ...n), and N is the total force in that member due to seismic loads.

133
Earthquake induced vertical loads equal to the product ck Q. S K are taken into consideration in the design of structural and non-structural

components and connections. Values for c are as follows:

c = + 4 for axial force when predominent in a member, for shear force

in girders and for gravity loads on large-span cantilever beams,

c = + 6 for concentrated vertical force on girders, punching shear force

on large-span flat slabs, and gravity load on heavily-loaded

cantilever beams,

c = + 5 for connections of post-tensioned structural members,

c = + 3 for connections at supports and of elements with heavy load concentrations due to seismic effects and for seismic forces normal

to wall surface of non-load bearing walls,

c = + 10 for seismic forces in any direction acting on balconies, cornices,

water tanks within buildings and industrial installations supported

by braced frames.

c = + 15 for seismic forces in any direction acting on parapets, ornamental

elements, statues, towers and stacks of low height.

Where the vertical resisting elements depend on diaphragm action for

distributing the shear at any level, the structure is designed for

torsional moments equal to the shear force times a distance e. This distance

is defined as follows: e = e + e2 where e-j = distance between mass and stiffness centers and e^ = c B. (c = 0.05 for ordinary structures, c = 0.075 for

2 e e e structures that have an unfavorable distribution in plan of the members resisting the earthquake-induced torsion, and B = maximum building dimension

in plan normal to the seismic force).

134

I

1
Special provisions for the design of foundation and basements specify

that buildings over 25m in height be provided with a rigid box construction

for the floor over the basement, basement walls and foundations. For

seismic zones 8 and 9, it is recommended that the floor over the basement

be cast in place in buildings with several stories.

Special provisions for seismic-resistant elements in cast-in-place reinforced concrete structures require (a) a minimum concrete strength equivalent

to grade B200, having a corresponding Romanian standard cube strength of approximately 20 MN/m^ (3,000 psi), (b) a minimum strength and ductility of steel

reinforcement conforming to grades 0B38 (380 MN/m or 55,000 psi) or PC52

(520 MN/m or 75,000 psi), (c) minimum negative reinforcement in beams at

column supports varying between 0.5% and 2% for 0B38 steel and between 0.4%

and 1.5% for PC52 steels, and corresponding minimum positive reinforcement

of 30% of the negative steel at the same location, (d) use of stirrups at

beam supports over a minimum distance equal to 25% of the span length and

(e) ultimate flexural strength in beams in excess of the ultimate shear

strength. For columns the minimum reinforcement requirements are (a) 1% and

0.8% of 0B38 and PC52 steels, respectively, for corner columns, and 0.8% and

0.6% of 0B38 and PC52 steels, respectively, for all other columns and (b)

use of ties spaced at 100mm or less for a height of 600mm or 1/6 the floor

height, whichever is less, at both column ends and extending over the beam

depth at supports. In addition, a recommendation is made against designs

of rigid (shear wall) structures resting on flexible columns at the ground

floor level. In the event that such structures are designed, the

code requires that the forces corresponding to Eq. 4.1 be increased by

135
25% in calculating the earthquake loads on columns supporting shear walls.

Special provisions for frame and shear wall structures require that

shear walls be designed for shear forces equal to 1.5 times those obtained

from Eq. 4.1. Where possible, it is recommended that frame structures be

so designed as to ensure development of plastic hinges in beams rather than

in columns under the action of earthquake loads. Additional special provisions for prestressed concrete, steel, masonry and wood structures and

non-structural elements are found in the P. 13-70 document.

4.4 Summary of Differences Between the P. 13-70 and the P. 13-63 Seismic

Design Requirements [4].

In P. 13-70, the P. 13-63 requirements have been reformulated to provide a more comprehensive view of the factors that influence the satisfactory

performance of structures subjected to seismic action. General provisions

have been included aimed at achieving structures with high ductility under

repetitive loading. A provision has been included that allows the use, in

special cases, of more advanced calculation procedures than those presented

in the requirements.

The provisions included in the P. 13-63 document pertaining to the

degree of seismicity assumed in calculations have been deleted, and the

notion of degree of seismicity used therein has been discarded. Instead,

the values of the seismic acceleration used in calculations (the coefficient

kg) have been specified as a function of the importance of the structure and

the degree of seismic intensity of the zone in which the structure is located.

136
In the P. 13-70 requirements, the values of have been so chosen that

the level of seismic protection is better balanced between the various

seismic zones and the classes of importance of the structures. For zone 8,

the value of k^ = 0.05 has been maintained. However, k^ has been changed

from 0.025 to 0.03 in zone 7, and from 0.10 to 0.08 in zone 9.

In view of the sensitivity of precast structures to seismic loads,

the P. 13-70 requirements stipulate that, in zones believed not to be seismic,

such structures shall be checked for a seismic load equal to at least the

minimum value specified in the requirements.

The spectrum curve representing the coefficient g has been modified,

the ratio between its maximum and its minimum value being reduced from

5 to 3.3.

On the basis of observations of the Mexico (1957), Niigata (1964)

and Anchorage (1964) earthquakes, B has been increased for structures on

poor foundation soils and decreased for structures on very stiff ground.

Provisions on limiting the effect of foundation rotation upon the

natural periods of vibration have been modified on the basis of recent

research.

Values of ij; have been specified for a larger number of structural

types as functions of damping and ductility in accordance with results of

U.S. research.

137
The limits within which it is necessary to consider higher vibration

modes, and the criteria for the superposition of the latter, have been

modified.

Additional criteria have been introduced pertaining to the vertical

seismic loads. Vertical loads in zone 8 have been reduced by 20% to 60%.

Seismic loads at supports and connections have been specified as functions

of k^. Additional seismic design provisions have been made for special

industrial installations.

Provisions have been introduced for checking lateral displacements

and other phenomena (cracking, accelerations, velocities).

Load combinations have been specified in a separate section (Appendix

I of the P. 13-70 requirements).

Additional provisions have been included in the P. 13-70 requirements

on the design for torsional effects induced by earthquake loads and on

the superposition of horizontal and vertical seismic loads.

Provisions have been added that take into account post-elastic

structural behavior and the favorable effect of ductility on structural

performance under seismic loads. These provisions include the following:

(1) At any given frame joint, the sum of moment capacities of columns

shall exceed the sum of moment capacities of beams; (2) An increase in

138
the horizontal shear force assumed to act on shear walls, to take into

account the absence of ductility; (3) To ensure a ductile behavior of

reinforced concrete members, higher grade concrete than was specified by

the P. 13-63 requirements shall be used in all structures designed tn

withstand seismic loads. Also, reinforcing steel is specified that exhibits

acceptable ductility. The reinforcement ratios are limited to moderate values.

Reinforcement shall be provided in compression zones undergoing earthquakeinduced stresses. It is also noted that the P. 13-70 provisions on spacing

and sizes of ties are more severe than those of the P. 13-63 requirements.

Restrictions on the height of large panel prefabricated structures

have been deleted. Provisions have been added aimed at improving the

construction and detailing of prefabricated structures, of masonry structures,

and on non-structural elements.

Provisions have been added pertaining to the design of tall structures,

viz, (a) the first floor of tall structures in zone 8 shall be cast-in-place;

(b) the design of structures with shear walls and a flexible ground floor

shall be avoided.

4.5 Microzoning of Bucharest

Figure 4.2 shows the microzoning map of Bucharest which was issued

in 1973 by the Romanian Institute of Standardization for use as a supplement

to the existing mandatory seismic design regulations (see Section 4.2). The

microzones in this map have been determined in accordance with the approach

139
established by Medvedev [7], taking into consideration the seismogeological features of the locality.

According to the seismic risk map of Romania shown in Figure 4.1,

Bucharest falls within seismic zone 7. In microzoning the city, seismic

zone increments are calculated on the basis of the depth of the hydrostatic

level below the ground and seismic rigidity Vp of the terrain using the

relation ,,V p C = 1.67 log — + e-^'^'^^ (4.5)

V p n^n

where designates the seismic zone increment, and designate the

speed of propagation of longitudinal waves in standard rock and soil under

consideration, respectively, p^ and are the respective densities of the

corresponding materials, and h is the depth of the hydrostatic level below

the ground surface. The standard material that is used as reference datum

for soils is usually granite.

The microzoning supplement contains a clause permitting correction of

the specifications of the standard, the designer assuming responsibility

for such correction with the advice and consent of the client, in the event

enough data is available that might lead to a different assessment of the

local geological factors involved. In addition, it calls for seismological

studies to be carried out at the site when designing structures of special

importance in accordance with the technical prescriptive documents currently

in force.

140
4.6 Summary of Seismic Provisions of the 1976 Uniform Building Code [8]

The total lateral seismic force assumed to act non-concurrently in

the direction of each of the p.rincipal axes of a structure is:

V = ZIKCSW (4.6)

where Z is equal to 3/16, 3/8, 3/4 and 1 in seismic zones 1, 2, 3 and 4,

respectively; I, the occupancy importance factor is equal to 1.5, 1.25 and

1 for essential facitities, buildings where the primary occupancy is for

assembly use for more than 300 persons in one room, and all other buildings,

respectively, K is a coefficient depending upon type or arrangement of

resisting elements (e.g., K = 1.33 for buildings with a box system; K=0.67

for buildings with a ductile moment resisting space frame with the capacity

to resist the total required lateral force; K=2.5 for elevated tanks on

four or more cross-braced legs and not supported by a building); C is a coefficient determined in accordance with the formula

C = -i- < 0.12 (^-7)

15VT

T being the fundamental period of vibration of the building or structure

in seconds in the direction under consideration; S is a coefficient determined in accordance with the formulas:

12 fnr T <1.0 (4-8)

s

's

- M

T. Lt,

S

= 1.0 + T - 0.5 {if- for T < 1

S

= 1.2 + 0.6 I

- 0.3 [ij^ for I >1

^^ ^^

being the characteristic site period (0.5s <T <2.5s), and W is the

total dead load plus the snow load if it exceeds 30 psf, plus 25 percent

of the floor live load in case of storage and warehouse occupancies. Where

141
is not properly established (see UBC Standard 23-1), S is taken as 1.5

except that if T > 2.5s, S may be determined by assuming = 2.5s. The

product CS need not exceed 0.14. The total lateral force V is distributed

over the height of the structure as follows:

V = F. + 2 F. (4.10)

^ i = l

^ Where F^, the concentrated lateral force acting at the top structure is

taken as 0 where T>0.7s and as F^ = 0.07 TV < 0.25V when T < 0.7s.

The remaining portion of the total base shear V shall be distributed

over the height of the structure including level n according to

n N (4.11)

where w^. is the portion of w located at or is assigned to level i, and h^. is

the height above the base to level i. Parts or portions of structures and

their anchorages are designed for lateral forces in accordance with

F^ = ZIC^SW^ (4.12)

P P P where W is the weight of the part or portion, and C is a coefficient

r r depending upon the part or portion being considered (e.g., C = 0.20 for

walls and partitions, C = 1.0 for cantilever parapet and ornamentation).

If C = 1.0, the values of I and S need not exceed 1.0.

P

142
143
0.5 0

I L

^,0 2 0 KM

-L 1

f I Microzone Limit

Railroad Tracks

Major Thoroughfares

Pigure 4,2, Microzone Map of Bucharest,

144
5. RECOMMENDATIONS

The authors developed a number of recommendations as a result of

their observations of the building performance described in this report.

Recommendations related to reconstruction of earthquake damaged buildings

and the development of improved building practices for future construction

are included.

RECOMMENDATION 1:

A SYSTEMATIC EVALUATION SHOULD BE MADE

OF ALL BUILDINGS IN BUCHAREST ERECTED

PRIOR TO THE ADOPTION OF EARTHQUAKE

DESIGN REQUIREMENTS AND A HAZARD ABATEMENT PLAN SHOULD BE DEVELOPED.

Inspections of damaged buildings are already being carried out by teams

of Romanian engineers. Quite naturally, these are concentrating on buildings

in which the visible damage was sufficient to raise doubts about their safety.

This program should be extended to include buildings which did not suffer

apparent extensive damage. Particular attention should be paid to the possibility of cumulative damage particularly progressive deterioration of

concrete with time. Such a program could mitigate the damages produced by

future earthquakes.

RECOMMENDATION 2:

CONSIDERATION SHOULD BE GIVEN TO THE INCLUSION

IN THE ROMANIAN DESIGN REQUIREMENTS OF MODERN

PROVISIONS FOR THE PREVENTION OF PROGRESSIVE

COLLAPSE.

The design of the computer building discussed in Chapter 3 illustrates

the need for such requirements. The building collapsed as a result of

column failures. However, failure of any one of the columns, particularly

the central column, was probably sufficient to incapacitate the structure

beyond repair. Had the design of the building incorporated, for instance,

concepts for the containment of local failures or for the provision of

alternate load paths to the foundation, it is possible that the extent of

the failure would have been significantly less.

RECOMMENDATION 3:

DESIGN REQUIREMENTS FOR BUILDING SEPARATIONS

SHOULD BE REVIEWED AND POSSIBLY IMPROVED.

The frequency of occurrence and extent of pounding damage resulting

from out-of-phase vibrations of adjacent buildings raise questions about

the adequacy of existing requirements for building separation. The damage

was observed in older buildings as well as those constructed under current

design requirements. Construction practices should also be reviewed to

145
ensure field compliance of building separation requirements specified by

design.

RECOMMENDATION 4:

ANALYTICAL AND EXPERIMENTAL STUDIES SHOULD

BE CARRIED OUT TO ASCERTAIN THE BEHAVIOR OF

THE PRECAST PANEL BUILDINGS SUBJECTED TO THE

EARTHQUAKE OF MARCH 4 IN BUCHAREST.

One of the advantages of precast panel building systems is the speed

of erection in the field [9]. Despite the fact that large panel systems

have been extensively utilized in Europe in the construction of apartment

buildings, a recent review indicates a general paucity of experimental

information on the subject [10]. The performance of the panel buildings

in Bucharest should therefore be studied in detail. Although the strong

motion record for the earthquake would seem to indicate that these buildings were not subjected to significant forces, this should be verified by digitizing the record and carrying out analytical time history studies. This is

particularly necessary before any conclusions are drawn regarding the possible

reassessment of the design requirements for panel builings. These buildings

should also be carefully inspected. Vibration tests could be carried out to

determine the natural periods for the buildings and comparisons made with

pre-earthquake measurements or calculations. These comparisons could reveal

the extent of any internal damage not immediately apparent through visual

inspection.

RECOMMENDATION 5:

A COOPERATIVE RESEARCH PROGRAM SHOULD BE

INITIATED BETWEEN THE UNITED STATES AND

ROMANIA IN THE FIELD OF LARGE PANEL

STRUCTURES.

In view of the potential for increased use of precast panel construction,

more data is needed on the performance of these systems under earthquake

loading. The behavior of the joints between the panels, their ductile capacity

and energy dissipative characteristics should be studied. A cooperative research

program could take advantage of the Romanian construction experience with panel

buildings, laboratory data on their dynamic performance available at INCERC and

the analytical and experimental research facilities available in the U.S.

RECOMMENDATION 6:

INCREASED ATTENTION SHOULD BE PAID TO

CONSTRUCTION QUALITY CONTROL IN ROMANIA.

The damage produced by the earthquake clearly indicated the need for

improved construction practices. Inadequacies in the amount of reinforcement and

cover, and in the spacing and anchorage of stirrups and ties providedin concrete

structures, and shortcomings in workmanship and the quality and quantity of

materials used in masonry construction are a few examples.

146
RECOMMENDATION 7:

THE RESPONSE SPECTRUM USED FOR DESIGN

PURPOSES IN ROMANIA SHOULD BE REEXAMINED.

The accelerograph record from the earthquake of March 4 would seem to

indicate a concentration of energy in the frequency range between 1 and

1.5 sec. Romanian engineers indicated that this also appeared to be the case for previous earthquakes. Available strong motion records could be

used to generate response spectra and statistical techniques employed to

select an appropriate design spectrum from the results [11].

RECOMMENDATION 8:

THE STRENGTHENING AND REPAIR PROCEDURES

ADOPTED FOR DAMAGED BUILDINGS SHOULD BE

AIMED AT REDUCING LARGE DIFFERENCES AND

DISCONTINUITIES IN STRENGTH AND STIFFNESS

BETWEEN ADJACENT FLOORS.

In many cases, building damage occurred as a result of large differences

in stiffness between the first and upper floors. The soft story behavior

observed in previous earthquakes was apparent. Repair techniques involving

only strengthening of the damaged elements in the lower stories will not

eliminate potential recurrence of a similar situation in future earthquakes.

The repair procedure should provide for increasing the stiffness of the lower

stories to make it more consistent with that of the stories above.

147
6. ACKNOWLEDGMENTS

The information presented in this report was obtained by the National

Bureau of Standards while participating as part of a technical assistance

team sent to Romania by the Agency for International Development (AID). The

authors appreciated the opportunity to be a part of the team. Special recognition is due AID for the initiative and foresight demonstrated in assembling

this team to provide assistance to Romania and to gather scientific and

technical data on damages caused by the earthquake of March 4, 1977.

Staff from the Office of Foreign Disaster Assistance, AID, including

E.E. Anderson, Christian Holmes, William Dal ton and Weston Emery were very

helpful in making necessary arrangements for the team.

Staff from the Building Research Institute (INCERC) in Bucharest, including R.T. Constantinescu , Scientific Director of the Institute and

G, Serbanescu, Head of the Structural Dynamics and Earthquake Engineering

Laboratory, were especially helpful in making arrangements for visiting

damaged buildings, setting up meetings with design engineers responsible

for reconstruction and providing background material on building design

and construction. Adriana Mihalus provided translation assistance and

served as a guide for the team.

148
Sidney Smith, Science Liaison Attache for the U.S. Embassy in Bucharest

provided assistance in obtaining technical information from the Government

of Romania on the earthquake damage to buildings. The authors appreciate

the assistance and hospitality of the United States Ambassador to Romania,

Harry Barnes.

Many of the photographs and all the structural drawings used in this

report were supplied by Romanian research, design and construction organizations.

Ann Heffernan and Linda Sacchet of the Office of Housing and Building

Technology typed the several manuscripts of the report.

149
7. REFERENCES

1. Beles, Aurel A. and Ifrim, Mihail, "Engineering Aspects of Earthquakes in

Romania in the Light of Modern Investigations," Proceedings of the

Second World Conference on Earthquake Engineering , Volume III,

Gakujutsu Bunken FukyuKai , Tokyo, Japan, Second Edition, 1965.

2. Von Hake, Carl A., Meyers, Herbert, "Earthquake Data File Summary,"

Environmental Data Service , National Oceanic and Atmospheric

Administration, Boulder, Colorado, May 1976.

3. Niculescu, Christea, "Die Gebaudeschaden des Bukarester Erdbebens vom

10 November 1940." Die Bautechnik , Heft 30/31, pp. 321-326, July 18,

1941 , Berlin.

4. Earthquake Resistant Regulations A World List 1973 , International

Association for Earthquake Engineering, c/o International Institute

of Seismology and Earthquake Engineering, Building Research Institute,

Tokyo, Japan, April 1973.

5. Titaru E. , and Cismigiu A., "On the Romanian General Design Specifications

for Civil and Industrial Buildings in Seismic Areas. Examples,"

Proceedings of the Second World Conference on Earthquake Engineering , Volume III, Gakajutsu Bunken Fukyu-Kai, Tokyo, Japan, Second Edition, 1965.

6. Provisions For The Design of Civil and Industrial Constructions in Seismic

Regions , P. 13-70, Colectia de normative si instructiuni , No. 44,

Redactia Publ icatiilor pentru Constructii, Bucharest, 1970 (in Romanian).

7. Medvfedev, S.V., Engineering Seismology , Gosudarstvennoe Izdatel'stvo

Literatury po Stroitel ' stvu, Arckhi tekture i Stroitel'nym Materialam,

Moscow, U.S.S.R., 1962 (in Russian). (English translation published

by Israel Program for Scientific Translations, Jerusalem, 1965, available

through U.S. Department of Commerce Clearinghouse for Federal and

Technical Information, Springfield, Virginia 22151).

8. Uniform Building Code , 1976 Edition, International Conference of Building

Officials, Whittier, California, June 1976.

9. "Ten Story Building Goes Up in 27 Days," Engineering News Record , April 14, 1977, pp. 99.

10. Zeck, Una Irelan, "Joints in Large Panel Precast Concrete Structures," Publ ica

tion No. R76-16 , Order No. 535, Massachusetts Institute of Technology,

Cambridge, Massachusetts, January 1976.

11. Newmark, N.M., Blume, J. A., and Kapur, K.K., "Seismic Design Criteria for

Nuclear Power Plants," Journal of the Power Division , ASCE, Volume 99, 1973,

pp. 287-303.

"12. Romanian Earthquake Disaster and Proposed A.I.D. Rehabilitation Program , A.I.D. Assessment Team Report, May 9, 1977.

150

1
APPENDIX A

COMPOSITION OF SURVEY TEAM AND SUMMARY OF ACTIVITIES

Members of the U.S. technical team which visited Romania following

the earthquake of March 4, 1977 included:

National Bureau of Standards

Charles Culver (Team Leader)

Disaster Research Coordinator

Center for Building Technology

George Fattal

Research Structural Engineer

Center for Building Technology

U.S. Geological Survey

S.T. Algermissen

Branch of Earthquake Hazards

T. Leslie Youd

Research Civil Engineer

Branch of Engineering Geology

Christopher Rojahn (joined team on 3/16/77)

Research Civil Engineer

Seismic Engineering Branch

Karl Steinbrugge

Consultant to U.S. Geological Survey

Bureau of Reclamation

Gerald F. Bowles

Concrete Dams Section

Frederick 0. Ruud

Head, Special Studies and Testing Section

Mechanical Branch, Design Division

Corps of Engineers

Ernest L. Dodson

Chief, Soil Mechanics Branch

Office, Chief of Engineers, U.S. Army

151
The following account summarizes the activities of the U.S. team

during their visit to Romania from March 14, 1977 through March 22, 1977:

March 14, 1977 - Team arrived in Bucharest. Met by Ambassador H.G. Barnes

and Science Attache Sidney Smith. Established residence

at Nuclear Physics Institute at Magurele, 15 km south of

Bucharest. Briefed by Chris Rojahn, USGS, on activities

of other U.S. investigators from National Academy of

Sciences and Earthquake Engineering Research Institute.

March 15, 1977 - Briefed by Romanian seismologists on the details of the

March 4 earthquake. Met with Head of National Council of

Science and Technology and representatives from Building

Research Institute and the Design institute (ICPT).

Visited damaged and collapsed buildings in central portion

of Bucharest.

March 16, 1977 - Team again met with National Council of Science and

Technology to discuss our work plans. NBS team members

later met with representatives from ICPT and discussed

the types of building construction in Bucharest. Also

visited damaged apartment building. USGS team members

(Algermissen, Steinbrugge) began collecting data for an

isoseismal map by surveying damage pattern throughout the

city. Youd visited INCERC and discussed the geotechnical

program underway there. BuRec and Corps of Engineers team

members met with Romanian counterparts concerned with dam

safety and planned site visits to dams and hydroelectric

152

i
plants. (Description of groups itinerary is not

included in this report).

March 17, 1977 - NBS team members and Youd visited Craiova and surveyed

damage to municipal building, museum and apartment complex.

Met with local engineers and discussed potential schemes for

damage repair and rehabilitating structures which had not

been designed for earthquakes. USGS team members continued

damage pattern survey in Bucharest.

March 18, 1977 - NBS team members visited modern buildings in Bucharest near

INCERC which had been damaged by the earthquake. Also visited

several large panel buildings in western portion of city which

had not been damaged. Youd met with representatives from ICPT

and discussed behavior of building foundations during the

earthquake. USGS team members continued damage pattern survey

in Bucharest.

March 19, 1977 - NBS team visited INCERC and discussed earthquake related

building research being carried out in Romania. NBS and

USGS team members met with U.S. Embassy personnel to discuss

the earthquake and answer questions of concern to them.

Youd visited epicentral area and Focsani checking rivers for

evidence of 1 iquefication and observing building damage in

vil 1 ages.

153
March 20, 1977 - NBS and USGS team members departed Romania.

Youd observed building performance and geotechnical effects

of the earthquake in the following cities: Galati, Braila,

Chiscani, Slobozia.

March 21, 1977 - Youd met with representatives from INCERC and discussed

elements for inclusion in a possible Romanian- American

cooperative geotechnical program.

March 22, 1977 - Youd departed Romania.

154
APPENDIX B

TEAM CONTACTS IN ROMANIA

During their visit, the NBS team members made contact with the following

individuals in Romania:

U.S. Embassy

Harry G. Barnes - U.S. Ambassador to Romania

Richard N. Viets - Deputy Chief of Mission

Richard Scissors - Economic Affairs Officer

Sidney G. Smith - Science Liaison Attache

Building Research Institute (INCERC)

Romulus T. Constantinescu

Horea Sandi

G. Serbanescu

T. Zorapapel

A. Mihalus (Interpreter)

Consiliul National pentru Stiinta Technologie

loan Ursu, Head, National Council of Science and

Technology

George Filipas

ICPT

Anatolie Cazacliu

Petru Vernescu

Center for Earth Physics and Seismology

Ion Cornia

United Nations Development Programme

B. R. Devarajan

155
156
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160 V U. S. GOVERNMENT PRINTING OFFICE : 1 977- -2'tO-8l48/3 1 It
NBS-1 14A (REV. 7-73)

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBS SP 490

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Observations on the Behavior of Buildings in the Romania

Earthquake of March 4, 1977

5. Publication Date September 1977

6. Performing Organization Code Center for Build. Tech.

7. AUTHOR(S)

George Fattal, Emil Simiu and Charles Culver

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Worlc Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Office of Foreign Disaster Assistance, AID

Department of State

Washington, DC 20523

13. Type of Report & Period Covered Final

14. Sponsoring Agency Code AID

15. SUPPLEMENTARY NOTES Library of Congress Catalog Card Number: 77-600035

Special report of observations by technical team sent to Romania by the Department of

State at the request of the Government of Romania following the earthquake of March 4, — 19^.

16. ABSTRACT (A 200-word or less factual summary of most sigftifleant information. If document includes a significant

bibliography or literature survey, mention it here.) Observations are presented of the damage to buildings resulting from the earthquake

of March 4, 1977 in Romania. The report was prepared by engineers from the National

Bureau of Standards who participated as members of the U.S. government team dispatched

to Romania under the auspices of the Office of Foreign Disaster Assistance, Agency for

International Development. A summary of the team's activities is included. Background

data on the seismic history of Romania, the characteristics of the earthquake and descriptions of damage to specific buildings are also included. The types of building con- struction and the history of the development of seismic design requirements for buildings in Romania are discussed. Recommendations are presented for needed building

research based on the observations

.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Buildings; building codes; earthquakes; natural disasters; structural engineering.

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