ANGLADESHETWORK OFFICE FOR
RBAN
AFETY
1

BUET, DHAKA, BANGLADESH

2
6

3

7

Prepared By:

17

15
5
8

4
18

14

12

13
16

9 10

19

11
20

41
43

40

45

Mehedi Ahmed Ansary

39

46

48

49

26

55

23

54

51
50

53
57

48

22

37

44

47

21

38

42

35

28
33

56
59

36 32

62
61
60

N

63
64
65

25
27

36

52
58

24
34

69 70

71
67
66 68
72
73

31

29
30

74
77
78
79

75

82

84
86
87
88

83
90

2000

0

2000

4000 Feet

Legend

85

76

80 81

89

Surveyed Zones
Polashi Zone
Tejgaon Zone
Baridhara Zone
Mohammadpur Zone
Siddique Bazar Zone
Mirpur Zone
Postagola Zone
Khilgaon Zone
Rail line
Water body
Ward Boundary

BNUS Annual Report-2010

CONTENTS
PART-I: DIAGNOSIS OF THE SEISMIC VULNERABILITY OF
BUILDINGS AT DHAKA USING NON-DESTRUCTIVETESTING---------------------------------------------------------------------- 1
PART-II: EVALUATION OF FIRE FIGHTING SYSTEM
AT HIGH-RISE BUILDINGS IN DHAKA CITY ---------------------19
PART-III: MICROTREMOR H/V TECHNIQUE FOR SITERESPONSE ANALYSIS---------------------------------------------------35
PART-IV: VULNERABILITY ASSESSMENT OF PUBLICBUILDINGS IN OLD TOWN --------------------------------------------47
PART-V: INSTALLATION OF A DIGITAL EARTHQUAKEMONITORING SYSTEM FOR BANGLADESH--------------------- 97
PART-VI: CHARACTERISTICS OF MICROTREMOR FOR A
110 MW POWER PLANT IN SOUTH WESTERNREGION OF BANGLADESH ----------------------------------------- 109
PART-VII: SEISMIC VULNERABILITY ASSESSMENT OFEDUCATIONAL BUILDINGS IN OLD DHAKA ----------------- 119
PART-VIII: MASON TRAINING PROGRAM ------------------------------ 151
PART-IX: WORKSHOPS, SEMINARS AND TRAINING
COURSES------------------------------------------------------------------ 155

PART-I
DIAGNOSIS OF THE SEISMIC
VULNERABILITY OF BUILDINGS AT DHAKAUSING NON-DESTRUCTIVE TESTINGBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Saidur Rahman
Mehedi Ahmed Ansary

ICUS Report 54

1. INTRODUCTION
The purpose of this study is to analyze the seismic vulnerability of buildings at various
locations in Dhaka city. In order to do this, checking structural elements in light of seismic
design and analysis of resonance phenomena between building and soil on the basis ofnatural frequency has been executed. Therefore, two non-destructive tests have been carriedout in this project. In addition, the seismic evaluation of buildings according to the first levelof screening procedure of the Japanese RC building seismic evaluation provision has also
been performed.
Ferroscanner, the electromagnetic detector to record image of reinforcements in concrete up
to 100 mm depth, is the efficient device for the identification of reinforcement if there is nofound basic design document or having contradiction to design in this building. Column andLift Core are the most important elements in any structural system. This is why the above
two structural elements along with slabs have been surveyed properly using Ferroscanner. In
this survey, detection of reinforcement includes number of reinforcement, spacing of
reinforcement, bar number and cover over the reinforcement. Eighty three buildings havebeen selected at six locations in Dhaka city as shown in Figure 1. These are Old Dhaka,
BUET campus, Lalmatia, Mirpur, Banani and Uttara.

Figure 1: Survey site at Dhaka city (Source: Google map)

1

March 2011

In addition, Microtremor is also used to record the fundamental frequency and period of
those buildings and soil. The dynamic properties are the important factor for seismic design.
Response of building mainly depends on the characteristics of both excitation forces anddynamic properties of buildings.

Figure 2: Seismic Microzonation Map for Dhaka City (After Rahman, 2005)
This is why the natural frequency and period is taken on the top of the roof of those building
to identify the dynamic properties of buildings. Furthermore, the vibration characteristics insoil are different from building. Hard soil gives high frequency and soft soil gives low
frequency. A structure may experience a vibration period at which it oscillates in theearthquake vibration motion and will tend to response to that. Natural frequency of structure
is obtained based on the spectral ratio of horizontal component of the building to that ofground. Meanwhile, practical application of Microtremor in the field of engineering has
advanced tremendously. One of the powerful and simplest applications of Microtremor
observation is in seismic micro zoning (see Figure 2).
From the data analysis of these building, most of the building are vulnerable due to moderate
seismic activity. In Old Dhaka, the majority of buildings are not constructed according toproper seismic design code. Some of these buildings are likely to be damaged because oflower intensity of earthquake. In BUET campus, about twenty nine buildings natural period
are not close to that of soil. So, they are out of danger of resonance and natural period of the2

BNUS Annual Report-2010

ICUS Report 54

remaining twenty one buildings are close to that of soil, so their seismic response can beconsiderably amplified. Results obtained from Ferroscan are not satisfactory. Variation ofcover and spacing of lateral ties in columns and stirrups in beam from design are above
acceptable limit. The buildings of three places like Lalmatia, Mirpur and Uttara arevulnerable due to medium seismic force. There is a significant variation in reinforcement inthose buildings. Some of them are vulnerable due to resonance.
2. CHECKING OF STRUCTURAL ELEMENTS USING FERROSCAN
Ferro-scanner, which detects reinforcements in concrete, is efficient device for the detectionof structural elements in a concrete building. There are many methods for the diagnosis of
the rebar arrangement like Electromagnetic method, X-ray measurement, and High energy
X-ray CT Scan and Radar inspection. In our survey, Electromagnetic method in
Ferroscanner has been utilized in the surveyed building.
When electric current run through a coil of the apparatus, magnetic field is formed. Electric
current is produced in the reinforcement bar because of the magnetic field. The field induces
electric current in the secondary coil to be measured. When electric current runs through acoil of the electro-magnetic sensor, magnetic flux is measured. Electromotive force of coilchanges due to magnetic flux. Thickness of clear cover or diameter of the reinforcement bar
can be estimated from magnetic flux change. Induced magnetic field depends on the distance
between sensor and reinforcement. When bars are too close, it becomes difficult to identify
the numbers of bar. The rebar detection ranges usually 120-150mm depending on bar size
and maximum depth is 180mm. Depth measurement ranges 100-140 mm depending in bar
size. However, depth accuracy is ±2.5 mm for most bars at common depth.
The Hilti PS 200 is a system used for high-end reinforcement detection. The importantelements of the system are the scanner, the monitor and the software. Scanner (PS 200 S) is
used to scan the reinforced concrete element whereas Monitor (PS 200 M) is used to show
the bar and to analyze on site (see figure 3(a)).

Figure 3(a): PS 200 Ferroscan system
3

March 2011

Figure 3(b): Column and slab checking using Ferroscan
For Ferroscan observation the team identified the column and marked them in drawing aswell as in the structural part of the building. Then they scan it carefully with the scanner andstore the data. The collected raw data were analyzed with help of the Ferroscan software.
Sometimes hardboard has been used to execute the scan efficiently. Figure 3(b) shows theprocess of Ferroscan and the reinforcement data in Villa Vatia.
3. MICROTREMOR OBSERVATIONFor Microtremor observation, sensors have been fixed on the floor of building at the
beginning. The sensor has been placed on the basis of long side and short side of building.
Three sensors have been located at different places to find out structural stiffness and natural
period.
SensorBatterCable
LaptopFigure 4: Microtremor data recording at Ameralo, Banani
One sensor has been fixed at the top of the building, one at the free field near the building
and other at any floor level of building. In this survey, approximately 60,000 data points
with sampling frequency 100 have been recorded. Sometimes observation of the twobuilding has been taken to save time. After taking the observation with the help of a program
the time domain velocity data is converted to frequency domain data and find out the natural
period of the buildings. Microtremor measurement instrument is shown below in Figure 4.
Soil characteristics can be assessed by Microtremor measurement. Hard soil gives highfrequency and soft soil gives long period. A structure may experience a vibration period at
4

BNUS Annual Report-2010

ICUS Report 54

which it oscillates in the earthquake vibration motion and will tend to response to that.
Natural frequency of structure is obtained based on the spectral ration of horizontal
component of the building to that of ground. The velocity spectrums along three directions
and response spectrums at different time interval in KING SHOPTAK RAJONIGANDA (MIRPUR)
are shown in Figure 4.

Figure 5: Velocity time history at X, Y and Z direction

Figure 6: Fourier spectrums of two time intervals of 20 seconds each (from 90 to 110
seconds and from 400 to 420 seconds, according to data recording)
Wave propagation mechanism of Microtremor and its relation with ground vibration
characteristics were studied from the beginning of Microtremor studies (Aki, 1957; Kanai
and Tanaka, 1961). There are two types of Microtremor observations. These are point andarray observations of microtremors (Ansary et al., 1996). From the array observation of
Microtremor of period greater than 1 sec, Rayleigh-wave and Love-wave originating fromnatural sources, such as sea wave, variation of air and wind pressure can be recognized. On
the other hand, short-period Microtremor of period less than 1 sec is thought to be generated
by artificial noises such as traffic vehicles, industrial plants, household appliances, etc. Some
researches (Sato et al., 1991; Tokimatsu and Miyadera, 1992; Tokimatsu et al., 1994) haveshowed that microtremors are mainly composed of Rayleight-wave and some (Nakamura,
1989; Wakamatsu and Yasui, 1995) have showed that short-period Microtremor bears
resemblance to shear-wave characteristics. Nevertheless, Microtremor can also be dominatedby Love–wave (Tamura et al., 1993). Recently, Suzuki et al. (1995) have applied
Microtremor measurements to the estimation of earthquake ground motions based on ahypothesis that the amplitude ratio defined by Nakamura can be regarded identical with halfof the amplification factor from bedrock to the ground surface. However, the real generationand nature of microtremors have not yet been established.
5March 2011

4. DATA ANALYSIS
In this study, about eighty three buildings have been checked on various points of view, suchas structural element checking using Ferroscan, resonance and stiffness criteria using
Microtremor, and the first level of screening procedure of Japanese RC building seismic
evaluation provisions (2001).
Table 1 shows the probability of resonance in surveyed places. On the other hand, Table 2
gives the structural vulnerability of building on the basis of Ferroscan. In addition to these,
Table 3 and Table 4 represent Seismic index of structure IS and of non-structural elements IN.
The most of the building in BUET campus are vulnerable in consideration of resonancebecause the predominant period of these buildings is close to that of the soil. However, someof them are unlikely to cause resonance phenomena. But there is structural disparity fromvarious points of view in according to our National Building Code (BNBC, 1993). The
building has major structural irregularities such as soft story, re-entrant corner, torsional
irregularity, soft story and story mass irregularity. Moreover, variation of clear cover is high.
Spacing of lateral ties in column is not as per code.
The buildings in Old Dhaka are likely to be occurred severe seismic hazard. Most of thebuilding, residential as well as religious purposes, is not built according to BNBC (1993). In
those areas, resonance phenomena are not analyzed, but, structural vulnerability has been
investigated properly. Variation of clear cover is high in most of the building. Spacing oflateral ties in column is not as per code. But, there are a few buildings in those areas which
are quite good in consideration of seismic activities. However, majority of the buildings arevulnerable not only for the seismic activity, but also fire or any other hazard.
The building in others areas, like Banani, Mirpur, Lalmatia and Uttara, are vulnerable due
structural irregularity as well as resonance. But, there are a few buildings in those areas
which are quite good in consideration of two important seismic activities. Furthermore, theconstruction quality of those buildings is not very well. Some buildings are not constructedaccording to our National Building Code.
Table 1: Microtremor data
Building Name andLocation
AMARELOStoreyof
Building
6

Observed period
T=
N/10
0.6

(sec)

Site period (sec)

X-

Y-

X-

Y-

direction

direction

direction

direction

0.44

0.35

0.2

0.2

ProbabilityofResonance
No

H#77/B, R#3, BLOCK#F, BANANNI

6

BNUS Annual Report-2010

ICUS Report 54

Building Name andLocation
King Shoptak

Storeyof
Building

Observed period
T=
N/10

(sec)

Site period (sec)

X-

Y-

X-

Y-

direction

direction

direction

direction

ProbabilityofResonance

7

0.7

0.34

0.45

0.25

0.25

No

9

0.9

0.32

0.39

0.30

0.30

YES

6

0.6

0.41

0.43

0.30

0.30

No

10

1

0.51

0.30

0.25

0.25

No

7

0.7

0.35

0.37

0.20

0.20

No

8

0.8

0.31

0.43

0.20

0.20

No

6

0.6

0.5

0.3

0.26

0.26

YES

4

0.4

0.5

0.5

0.7

0.65

No

11

1.1

0.4

0.4

0.3

0.3

No

7

0.7

0.26

0.39

0.5

0.33

No

7

0.7

0.37

0.37

0.25

0.25

YES

Rajoniganda, 2
2/C, AVENUE-3, PLOT3, HAZI ROAD,
MIRPUR-2
MI-NIBASH
H# 1/3, R#19,BLOCK#B,
SECTION #10,
MIRPUR, DHAKA-1216
NHB
15/3, Ibrahimpur,Mipur14
RIDGE VALLEY
H#29, R#7, BLOCK#F,
BANANI MODELTOWNVILLA VATIA
H#3/8,BLOCK#E,LALMATIA,DHAKA-1207
SUVASTU SARINA
H#1/4,BLOCK#F,LALMATIA, DHAKA-1207
TOTAL GODHULI
PLOT-16, SECTOR-10,
ROAD-11, UTTARA
R/A, DHAKAIFCDR Building
BUET CAMPUS
Eleven Storey Tower
Building
BUET CAMPUS
Civil Engineering
Building
BUET CAMPUS
EME Building

7

March 2011

Building Name andLocation

Storeyof
Building

Observed period
T=
N/10

(sec)

Site period (sec)

X-

Y-

X-

Y-

direction

direction

direction

direction

ProbabilityofResonance

BUET CAMPUS
Library Building

5

0.5

0.33

0.36

0.25

0.26

No

5

0.5

0.26

0.38

0.4

0.4

YES

5

0.5

0.27

0.3

0.4

0.4

YES

5

0.5

0.18

0.3

0.5

0.26

No

12

1.2

0.27

0.18

0.32

0.35

No

5

0.5

NA

NA

0.3

0.35

YES

4

0.4

NA

NA

NA

0.52

YES

4

0.4

0.24

0.27

0.38

0.52

NO

4

0.4

0.32

0.27

0.38

0.31

YES

4

0.4

0.32

0.32

0.32

0.38

YES

6

0.6

0.39

0.34

0.38

0.32

YES

6

0.6

0.32

0.28

0.3

0.3

YES

6

0.6

0.4

0.38

0.3

0.3

YES

5

0.5

0.3

0.3

0.3

0.23

YES

4

0.4

0.27

0.25

0.07

0.06

YES

BUET CAMPUS
Architecture Building
BUET CAMPUS
URP Building
BUET CAMPUS
ARC Building
BUET CAMPUS
New Academic Building
BUET CAMPUS
Controller of
Examination building
BUET CAMPUS
Engg. University School
Building
BUET CAMPUS
Titumir Hall
BUET CAMPUS
Sher-e-Bangla Hall
BUET CAMPUS
Dr. M.A. Rashid Hall
BUET CAMPUS
Building Number 47
BUET CAMPUS
Building Number 62
BUET CAMPUS
Fire Service Station(Head Office, Dhaka)
BUET CAMPUS
Ban Bhaban Main
Building
BUET CAMPUS
Fire Service Station,
LalbagBUET CAMPUS

8

BNUS Annual Report-2010

ICUS Report 54

Building Name andLocation
Shahid Smirity HallStoreyof
Building

Observed period
T=

(sec)

N/10

Site period (sec)

X-

Y-

X-

Y-

direction

direction

direction

direction

ProbabilityofResonance

4

0.4

0.3

0.28

0.18

0.07

YES

5

0.5

0.2

0.2

0.32

0.3

No

middle Building
BUET CAMPUS
Shahid Smrity Hall north
Building
BUET CAMPUS

Note: X = Long direction and Y = Short direction
Table 2: Data analysis (Ferroscan)
Building Name andAdequacy of Reinforcement

Location

Structural
Vulnerability

ColumnSlabBeam/shear
wall

TEACHERS' QUARTER

not okok

not tested

moderateokok

not tested

moderate

not okok

not tested

moderate

not oknot oknot tested

high

not oknot oknot tested

high

ok

ok

not okmoderate

not okok

not tested

moderateokok

not tested

moderate

47/1-6, BUET campus
AMARELO
H#77/B, R#3, BLOCK #F,
BANANNIKing Shoptak Rajoniganda,
2
2/C, AVENUE-3, PLOT-3,
HAZI ROAD, MIRPUR-2
MI-NIBASH
H# 1/3, R#19,BLOCK#B,
SECTION #10, MIRPUR,DHAKA-1216
NHB 15_3
15/3, Ibrahimpur,Mipur-14
RIDGE VALLEY
H#29, R#7, BLOCK#F,
BANANI MODEL TOWNVILLA VATIA
H#3/8, BLOCK#E,
LALMATIA, DHAKA1207
SUVASTU SARINA
H#1/4,BLOCK#F,

9

BUET CAMPUS

Note: X = Long direction and Y = Short direction

March 2011

Table 2: Data analysis (Ferroscan)
Building Name andAdequacy of Reinforcement

Vulnerability

Location
LALMATIA, DHAKA-

ColumnSlab1207
TOTAL GODHULITEACHERS'QUARTER

Structural

Beam/shearwall

not okokok
not tested

highmoderateokok

not tested

moderate

Islampur Jame Mosque
BANANNInot oknot tested

not tested

high57, 58;Islampurroad
King
ShoptakRajoniganda,

not okok

not tested

moderate

2Jhubbu Khanam Jame

not oknot tested

not testedHigh

not oknot okok
not tested

high

not oknot tested

not tested

highChakrobarti
NHB
15_3 Road

not oknot oknot tested

high

15/3,
Ibrahimpur,Mipur-14
Malibagh(Bangshal)
Peyalaok

not oknot tested

moderate

Mosque VALLEY
RIDGE

ok

ok

not okmoderate

BANANI
MODEL
Kosaituli Old
Jame TOWN
Mosqueokok

not tested

moderate

26/27, K.P.
Ghosh Street
VILLA
VATIA

not okok

not tested

moderate

H#3/8,BLOCK#E,
Bangshal
RokonUddin

not okok

not tested

moderateokok
not oknot tested

moderate

not okok

not tested

moderate

Not oknot oknot tested

moderate

Mokimbaza schoolok

not tested

not tested

quite good

Mahuttuli primary School

not okok

not tested

moderate

PLOT-16,
SECTOR-10,
47/1-6,
BUET
campusROAD-11, UTTARA R/A,
AMARELODHAKA R#3, BLOCK #F,
H#77/B,

Mosque2/C,
AVENUE-3, PLOT-3,
24, Islampur
HAZI
ROAD,road
MIRPUR-2
Kamranga Jame Mosque
MI-NIBASH
Zindabahar
1st LaneH#
1/3, R#19,BLOCK#B,
SECTION#10, MIRPUR,
Mahuttuli Jame
MosqueDHAKA-1216
55,Sharat Chandra

Bongshal
Road
H#29,
R#7,
BLOCK#F,LALMATIA,
Jame Mosque DHAKA1207
Bongshal RoadSUVASTU
SARINA
Anondomoyee
Girls's HighH#1/4,BLOCK#F,
School17,18 ,Kazi Muddin
Siddque Street
Haybotnagar Primary
School13,'Haibat Nagar Dewan
Jummon Community Centre
19-1,19-2(I),'Hazi Abdur
Rashid Lane

27, Sharat Chandra
Chakrobarti Road

10

BNUS Annual Report-2010

BUET CAMPUS

Note: X = Long direction and Y = Short direction

ICUS Report 54

Table 2: Data analysis (Ferroscan)
Building Name andAdequacy of Reinforcement

Vulnerability

Location
Nobab Yousuf Market

Structural

not okColumnnot okSlabMosquenot okBeam/shear

high

wall

Nobab Eusuf RoadTEACHERS'QUARTERnot okok

not tested

moderate

ShahjadaMia
Mosque47/1-6,BUETJame
campusnot okok

not tested

moderate

24, Shahjada Mia Lane
AMARELOokok

not tested

moderate

Jindabahar
Jame
MosqueH#77/B,
R#3,
BLOCK
#F,

not oknot oknot okhigh

not okok

not tested

moderateok

not oknot tested

moderate

45, Bagdasha Lane
MI-NIBASH

not oknot oknot tested

high

H#
1/3, R#19,BLOCK#B,
Samsabad
Boro Mosqueok

not oknot tested

moderate

DHAKA-1216
Kosaituli panchayetokok

not tested

moderate

NHB
15_3 and School
Committee

not oknot oknot tested

highStreet VALLEY
RIDGE

ok

ok

not okmoderate

H#29,
R#7,Ghat
BLOCK#F,
Babubazar
Jame

ok

ok

not tested

moderate

Ray Eshar
Chandra Ghosh
VILLA
VATIA

not okok

not tested

moderate

H#3/8,
Ahmed BLOCK#E,
Bawani School andnot okok

not tested

moderateok
not okok

notnottestedokmoderate

not oknot oknot okhigh

not okokok

not oknot tested

moderateokok

not okmoderate

not okok

not okmoderate

54, Zindabahar 1st Lane
BANANNI
Maulana
MosqueKing
ShoptakRajoniganda,
297/98, K.P. Ghosh Street
2/C,
AVENUE-3,
PLOT-3,
Shahjadi
Begum Jame
HAZI
ROAD, MIRPUR-2
MosqueSECTION
MIRPUR,
K.P. Ghosh#10,
Street15/3,
Ibrahimpur,Mipur-14
9, Kazi
Muddin Siddque

BANANI
Mosque MODEL TOWNLALMATIA,
DHAKACollege
1207
3/4, K.P. Ghosh Street
SUVASTU
SARINA
Samsabad Primary
SchoolH#1/4,BLOCK#F,
79, K.P. Ghosh Street
Kona Party Centre
11-12,S.C.C Road
Ahmedabad schoolmoderate

3/4, K.P. Ghosh Street
Mosjid-e-Baitul-Mamur
69 French Road, Mosjid-eBaitul-Mamur
IFCDR Building
BUET CAMPUS
Eleven Storey Tower
Building
BUET CAMPUS

11

BUET CAMPUS

Note: X = Long direction and Y = Short direction

March 2011

Table 2: Data analysis (Ferroscan)
Building Name andAdequacy of Reinforcement

Vulnerability

Location
Civil Engineering Building

not okColumnok
Slab

BUET CAMPUS
EME BuildingQUARTERTEACHERS'

Structural

not okBeam/shear

moderatewall
not okokok
not tested

moderate

not okokok

not tested

moderate

BANANNI
Architecture Building

not okok

not okmoderate

BUETShoptak
CAMPUSKing
Rajoniganda,

not okok

not tested

moderate

2URP Building

not okok

not okmoderate

HAZI
ROAD, MIRPUR-2
ARC Building

not okok

not okmoderate

MI-NIBASH
BUET CAMPUS

not oknot oknot tested

high

H#
R#19,BLOCK#B,
New1/3,
Academic
Building

not okok

not okmoderate

DHAKA-1216
Controller of Examination

not okok

not ok

high

NHB
15_3
building

not oknot oknot tested

high

ok
not okok
not tested

not okmoderate

not okok
not oknot testedokmoderate

not oknot oknot okmoderateok
not okok
not oknot testedokmoderateok

not testedokmoderate

ok

ok

ok

moderate

not oknot oknot okmoderateok

not tested

not okmoderateok

not tested

not okhigh

BUET CAMPUS
47/1-6,
BUET campus
Library Building
AMARELO
BUET CAMPUS
H#77/B,R#3, BLOCK #F,

2/C,
AVENUE-3,
BUET
CAMPUS PLOT-3,

SECTION#10, MIRPUR,
BUET CAMPUS

15/3,
BUETIbrahimpur,Mipur-14
CAMPUSRIDGE
VALLEYSchool
Engg. University
H#29,
R#7, BLOCK#F,
Building
BANANI
MODEL TOWNBUET CAMPUS
VILLA
Titumir VATIA
Hall
H#3/8,BLOCK#E,
BUET CAMPUS
LALMATIA,
Sher-e-BanglaDHAKAHall
1207
BUET CAMPUS
SUVASTU
SARINA
Dr. M.A. RashidHall
H#1/4,BLOCK#F,BUET CAMPUS
Building Number 47
BUET CAMPUS
Building Number 62
BUET CAMPUS
Fire Service Station (Head
Office, Dhaka)
BUET CAMPUS
Ban Bhaban Main Building
BUET CAMPUS
Ban Bhaban Extended
PortionBUET CAMPUS

12

BNUS Annual Report-2010

BUET CAMPUS

Note: X = Long direction and Y = Short direction

ICUS Report 54

Table 2: Data analysis (Ferroscan)
Building Name andAdequacy of Reinforcement

Vulnerability

LocationFire Service Station, Lalbag

okColumnnot okSlabBUET CAMPUS
ahsan-Ullah hall
TEACHERS'QUARTER

Structural

not tested
Beam/shear

moderatewall
not oknot okokok
not tested

highmoderate

not okokokok tested
notmoderate

not okokok tested
notmoderate

BUET CAMPUS
47/1-6,
BUET campus
Shahid Smirity Hall middle
AMARELO
Building R#3, BLOCK #F,
H#77/B,
BUET CAMPUS
BANANNI
ShahidSmrityRajoniganda,
Hall northKing
Shoptak
2Building
BUET
CAMPUS PLOT-3,
2/C,
AVENUE-3,
HAZI ROAD, MIRPUR-2
MI-NIBASH

not oknot oknot tested
high
5. SEISMIC EVALUATIONFOLLOWING
THE FIRSTLEVEL OF SCREENING

H# 1/3, R#19,BLOCK#B,

PROCEDURE

SECTION #10, MIRPUR,

The provisions of the Standard of Japanese RC building evaluation (2001) is applied to

DHAKA-1216

seismic
reinforced
concreteof Dhaka. The seismic
NHB
15_3 evaluation of existing
not oknot oknot tested buildings
high
15/3,
Ibrahimpur,Mipur-14
evaluation
is done based on both site inspection and structural calculation to represent the
RIDGE
okokterms of seismic
not ok indexmoderate
seismicVALLEY
performance of a building
inof structure IS and seismic index
H#29, R#7, BLOCK#F,

of non-structural elements IN. The seismic safety of the building shall be judged based on

BANANI MODEL TOWN

standard for judgment on seismic safety wherein seismic performance demands are

VILLA VATIA

prescribed.
H#3/8,BLOCK#E,

not okok

not tested

moderate

LALMATIA,
DHAKAThe standard
is applied to the seismic evaluation and the verification of seismic retrofitting
1207
of existing low-rise and medium-rise reinforced concrete buildings. Three levels of
SUVASTU SARINAokok
not tested
moderate

screening procedures, namely the first, the second, and the third

H#1/4,BLOCK#F,

level screening procedures, are available for the seismic evaluation according to thisstandard. In the present study first level of screening procedure is used.
The seismic index of structure IS can be calculated at each story and in each principal

horizontal direction of a building. Here the index has been calculated for a typical story inweak direction. The seismic index of structure includes basic seismic index of structure EO,
irregularity index SD and time index T. The basic seismic index of structure EO evaluates thebasic seismic performance of the building. It is calculated at each story and each direction
based on the ultimate strength, failure mode and ductility of the building. These effects are
considered by applying the strength index C, the ductility index F and the effective strength
factor α. The vertical structural members are classified into three categories as column,
extremely short columns and wall, according to the provision. The strength index in the first13March 2011

level of screening procedure is calculated approximately using the cross sectional area ofwalls and columns. The irregularity index SD and time index T are used commonly for all
stories and directions in the first level of screening procedure. The irregularity index SD is tomodify the basic seismic index of structure EO by quantifying the effects of the shapecomplexity and the stiffness unbalance distribution, and the seismic performance of astructure with engineering judgment. The time index T evaluates the effects of the structuraldefects such as cracking, deflection, aging and like on the seismic performance of a structure.
Seismic index of non-structural elements IN is to judge the safety of human lives or the
security of evacuation routes against the fall-down or the spall-off of non-structural elements,
especially external walls. IN shall be calculated by following the procedures provided for the
first level screening procedure for each wall in each story. In current seismic evaluation IN iscalculated for the walls based on the representative condition present in a specific story of abuilding. The seismic index of non-structural elements includes construction index andhuman risk index which shall be adopted for the external walls considering the mostvulnerable construction method, that is, which gives the maximum value of the construction
index, among the walls concerned. The construction index is calculated from conformability
index and deterioration index. The conformability index is determined in combination ofductility grade of the primary structure and ductility grade of non-structural elements. The
deterioration index is based on aging and past damages. The human risk index is based on
the condition of usage below the external wall and the existence of guard such as the eaves,set back and the like.
Seismic safety of a building shall be judged by comprehensive assessment based on theseismic evaluations separately conducted on the structure and non-structural elements.
Seismic safety of structure is judged by comparing the seismic index of structure and theseismic demand index of structure ISO. The building may be assessed to be safe if thebuilding possesses the seismic capacity required against the expected earthquake motions.
Otherwise the building should be assessed to be uncertain in seismic safety. The seismic
demand index of structure ISO is calculated for first level of screening, based on the basic
seismic demand index of structure ES taken as 0.8, zone index Z as 1.2 (Rahman G.F., 2004),
ground index as 1.0 and usage index as 1.0, regardless of the story in the building.
The index calculated for the seismic evaluation of a few selected buildings is enumerated inTable 3 and comment on their safety judgment is shown in Table 4.

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ICUS Report 54

Table 3: Seismic index of structure IS and of non-structural elements IN
No. of Stories,

Buildingn

No of Storyfor Evaluation,

EO

SD

T

IS

B

H

IN

i

IFCDR Building

4

2

0.602

1.2

0.9

0.65

0.8

0.5

0.6

Titumir Hall

4

2

0.458

1.14

0.8

0.42

0.8

0.5

0.6

New Academic Building

12

2

1.494

1.14

1

1.70

0.8

0.5

0.6

M A Rashid Hall

5

2

0.702

1.14

0.8

0.64

0.8

0.5

0.6

Library Building

4

2

1.148

1.14

0.8

1.05

0.8

0.5

0.6

ARC Building

4

2

0.761

1.2

1

0.91

0.8

0.5

0.6

7

2

0.902

1.14

0.8

0.82

0.8

0.5

0.6

Civil Engineering
Building

Table 4: Comment on safety judgment

Building

No ofStories, n

Seismic Indexof Structure,
IS

Seismic Index of

Seismic Demand

Non-Structural

Index of

SafetyElements,

Structure,

Judgment

IN

ISO

IFCDR Building

4

0.65

0.6

0.96

Uncertain

Titumir Hall

4

0.42

0.6

0.96

Uncertain

12

1.70

0.6

0.96

Safe

M A Rashid Hall

5

0.64

0.6

0.96

Uncertain

Library Building

4

1.05

0.6

0.96

Safe

ARC Building

4

0.91

0.6

0.96

Uncertain

7

0.82

0.6

0.96

Uncertain

New Academic
Building

Civil
Engineering
Building

6. CONCLUSIONSIn this study, the seismic vulnerability of low and medium-rise reinforced concrete buildings
within six major locations of Dhaka city was investigated. The seismic evaluation has beenaccomplished by performing two non-destructive tests, Ferroscan and Microtremor
measurements and also following the Japanese RC building seismic evaluation provision.
The inspection was done by observing the structural elements and building configuration
along with the resonance phenomena of the building.
Total 84 buildings have been selected for the study. Most of the buildings in BUET campus
are vulnerable in consideration of resonance. Those buildings have major structural
15

March 2011

irregularities such as soft story, re-entrant corner, torsional irregularity, and mass irregularity.
The poor structural quality has been identified in most of the building in Old Dhaka. Thesebuildings have the most probability to face seismic hazard. Consequently, it could be greater
threat for the people of these areas. The buildings in other areas, like Banani, Mirpur,
Lalmatia and Uttara, are vulnerable due to structural irregularity as well as resonance.
On the other hand, the vulnerability assessment of the seven arbitrary buildings has been
performed according to the first level of screening procedure of the Japanese provision.
Among these buildings, two buildings may be declared as safe on the basis of seismic safetyof structural elements since they own the required seismic capacity against the expectedearthquake motions. While other five buildings may be evaluated as uncertain in seismic
safety and detail analysis is required to confirm this situation.
Therefore, in light of study, it may be recommended that proper planning and better
construction quality are required in future building to combat the seismic activity as well as
fire hazard. Moreover, retrofitting technique for the risky buildings in these places.
REFERENCES
Aki, K. (1957). Space and time spectra of stationary stochastic waves, with special reference
to microtremors, Bull. Of earthquake research institute, 35, 415-456.
Ansary, M.A., Yamazaki, F. and Katayama, T. (1996). Application of Microtremor
Measurements to the estimation of site amplification characteristics, Bulletin of ERS,Vol 29, PP: 96-113.
Bangladesh National Building Code (1993). Housing and Building Research Institute, 1st ed.,Dhaka.
Kanai, K. and Tanaka T. (1961). On Microtremor VIII, Bull. Earthq. Res.Inst. Tokyo
University, Vol.39, PP. 97-114.
Nakamura, Y. (1989). A method for dynamic characteristics estimation of subsurface using
microtremor on the ground surface, QR of RTRI, 30, PP. 25-33
Rahman, G. F. (2004), Seismic Damage Scenario for Dhaka City, M. Sc. Thesis, Department
of Civil Engineering, Bangladesh University of Engineering and Technology.
Standard for Seismic Evaluation of Existing Reinforced Concrete Buildings (2001).
Tamura, T., Nagai, O., Kikubo, H. and Sumita, H. (1993). Charactesistics of wave group
microtremors obtained by array measurement, J. Struct. Consr. Eng. AIJ 449, PP. 8391 (in Japanese).

16

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ICUS Report 54

Toshinawa, T., Inoue, M., Yoneyama, N., Hoshino, Y., Mimura, K. and Yokoi, Y. (2003).
Geologic-profile estimates of Kofu Basin, Japan, by making use of microtremor
observations, Geophysical Research Abstracts, Vol. 5, 02079.
Sato, T., Kawase, H., Matsui, M. and Kataoka, S. (1991). Array measurement of highfrequency microtremors for underground structure estimation, proc. 4th int. conf. onseismic zonation, 11, PP. 409-416.

17

PART-II

EVALUATION OF FIRE FIGHTING SYSTEM
AT HIGH-RISE BUILDINGS IN DHAKA CITYBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Tanjina Afrin, Sharmin Ara
Mehedi Ahmed Ansary

ICUS Report 54

1. BACKGROUND
A fire hazard is any situation in which there is a greater than normal risk of harm to people
or property due to fire. Urban fires have devastating impact on communities. Unplanned
urbanization and rapid industrialization are the major causes of huge number of fire related
accidents in Dhaka city and increase the vulnerability of the country’s major population andeconomic centers. Dense building concentrations, narrow roads, flammable building materials
and electrical system as well as the lack of resources to raise awareness and response skills
have resulted in a growing risk of large scale, multiple structure fires.
Fire incidents are very common in Dhaka city, especially in relatively densely populated areas.
The damage of property and loss of human life are intensified by different factors. The extent
of loss due to fire incidents has an increasing trend and it is shown in Figure 1.

Figure 1: Extent of losses due to fire hazards in different years
A developing country like Bangladesh cannot afford the huge amount of loss caused by fire
accidents every year. Moreover, fire incidents in shops, industrial and commercial buildings
cause heavy toll of life and property. The fire incidents are on an increase due to lack ofawareness, almost no feeling for following safety measures and practicing fire fighting drills,
violation of building codes and non- compliance with the Fire fighting and ExtinguishingLaw 2003.
Some recent flagitious fire incidents in Dhaka city have stimulated a detailed study on highrise buildings about fire safety and awareness. This study depicts an overview on overall
condition of existing fire fighting system and on awareness level among the occupants ofhigh rise buildings in Dhaka city.
19March 2011

2.

MAJOR CAUSES OF FIRE INCIDENT IN BANGLADESH

Common Causes of fire are smoking, welding or cutting operation and use of blow lamps,
sparks from power unit, short circuit and over loading of electrical current, children playing
with crackers, ignition by chemical action/spontaneous combustion, gross carelessness,
malicious, deliberate during riot or strike, lightening, earthquake etc (see Figure 2). Fire at
garments is very common in Bangladesh, major fire incidents take place due to unplanned
construction of buildings being used by garment factory owners. Most of the buildings did
not follow the building code and lacked arrangements for alternative staircases andemergency exits and fire fighting equipment. Keeping collapsible gates under lock and key
in the name of security is the main cause of increases casualties in the incidents. According
to the statistics, the major accidents occurred due to electric shot circuits. The highest 3334
accidents took place in 2006, 2787 in 2005 and 2522 in 2004,( The New Age, February 10,2007) (see Figure 3).
High-rise buildings now being constructed in different parts of the city is in lack of theminimum safety features and endangers both adjoining structures and public thoroughfares.
Many of the high-rises have been constructed without proper planning, ensuring adequate
structural strength, without taking the proper safety measures and considering environmental
factors.

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Figure 2: Causes of fire incident in Bangladesh

Figure 3: Trends of fire incident in Bangladesh (The New Age, 2009

3. RECENT SEVERE FIRE INCIDENTS IN BANGLADESH
In Bangladesh, especially in Dhaka and Chittagong city, fire is becoming an unmanageable
threat particularly in high rise buildings mostly constructed violating the national building
code. Various incidences of major occurrence of fires in different type buildings are given
below.

21

March 2011

I.

Fire in BSEC Bhaban
A devastating fire broke out at the Bangladesh Steel and Engineering Corporation (BSEC)
Bhaban in the capital on 26 February 2007. Several witnesses said the fire originated fromelectric oven; while some others said it was sourced from electric short-circuit. There were
fire extinguishers on almost all the floors but none dared to use them. This building’s neither
has any emergency exits nor a sufficient number of fire-fighting equipment and operators to
use them during fire. There was also no fire lift but a switched off lift. Acute shortage ofwater and inadequate equipment hampered the rescue operation. Three persons were killed
and more than 100 injured in this incidence. NTV, RTV offices totally burnt and went off air.
(www.thedaily star.net)

Photograph 1: Smoke billows out of the BSEC building and victims trapped in
the fire that caught the building come down a ladderII.

Bashundhara FireOn 13 march 2009, Friday at about 1-45pm, a hell fire engulfed the upper levels of 20 storey
office cum shopping centre known as Bashundhara City Complex at Panthopath, Dhaka
killing 7 and injured 20 people. Though the building was equipped with sufficient fire
detecting, suppressing, and evacuating systems but they were useless during the fire. From
the fire Brigade sources it was known that complex's water reservoir remained empty, thehydrants were useless as there was no water in the tank. Due to faulty fire fighting system,
the fighters of the building didn't care about those warnings though the fire alarm on the 18th
floor, where the fire broke out first, gave false alarm 18 times during the same period.

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Photograph 2: Fire engulfing the Bashundhara City market
III. Terrible fire incident in Nimtoli at Old Dhaka
An overwhelming fire broke out in the densely-populated part of Old Dhaka city at Nimtoli.
Fire devoured at least 117 people and causing injury about hundreds of people at 3rd June,
2010. Most of the affected peoples were women and children. Initially it was thought that
explosion of two transformers at Nimtoli started the fire but later it has been known the fire
originated from an oil stove and spread to the chemical warehouses nearby and resulted highcasualty figures and damages. It is common scenario in Old Dhaka that most of the buildings
have small factories i.e. chemical, plastic, rubber etc., and ware house and food shops up tosecond floor of the residential building. In Old Dhaka no house is equipped with fire fighting
equipments like extinguisher, hose pipe etc. They don’t have sufficient width of staircase letalone the emergency exit. (www.thedaily star.net)

Photograph 3: Fire engulfing the Bashundhara City market
IV.

Fire in KTS textile mills
91 killed in a fire in KTS textile mill, Chittagong, February 23, 2006. At least 500 workers
were inside the mill when the fire broke out. Most of the survivors had to jump from
windows as the only exit from the factory was reportedly locked when the fire broke out late23

March 2011

on a Thursday night. Most of the victims were women, trapped by the flames or suffocatedfrom smoke inhalation. The fire might have been caused by an electrical short circuit. The
explosion of a boiler escalated the blaze. (www.thedaily star.net)
After analyzing the past incidents and accidents, some terrible facts are revealed. In mostcases imperfect arrangements and training of the safety equipments such as fire alarm,smoke alarm, fire extinguishers, water supply system etc., lack of proper exit route to reachthe place of safety ,routes are blocked by different materials ,lack of signage for escape routeand emergency lighting, adequate doors as well as adequate staircases are not provided to aid
quick exit , fire exit or emergency staircase lacks proper maintenance , lack of proper exit
route to reach the place of safety and most importantly lack of awareness among theresidents, workers and the owners are the main causes of heavy toll of life and property.
4. EXISTING CONDITION OF FIRE FIGHTING SYSTEM IN DHAKA CITY
For the evaluation of fire fighting system in Dhaka city a questionnaire survey was
conducted to assess the existing condition of total fire fighting system, awareness level of the
respondent and their evacuation plan during fire catch up. To have overall scenario regarding
fire safety, 2.5% buildings (includes residential, commercial, garments and institutional etc.)
of 2150 (according to Dhaka City Corporation, total no. of high rise building) has beensurveyed from 9 zones (Department of Fire Service and Civil Defense divided Dhaka City
into 12 zones) and most of them are above 8 storied (see Map1). Figure 4 and Figure 5 show
number of study buildings and existing use of the buildings in percentage respectively.
Another objective of this study was to determine the awareness level of occupants of thesurveyed buildings. 64% and 80% of total respondents know about earthquake and fire
respectively but only a little number of respondents has any evacuation plan about fireincidents.

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Figure 4: Number of study buildings by storey (in %)Figure 5: Use type of high rise building

25

March 2011

1

2
6

17

15
5
8

3

7

4
18

14

12

13
16

9

10

19

11
20

41
43

42
40

45

22

37

44

39

46
47

21

38

48

49

23

54

51
50

35

53

28
33

56
59

36

62
61
60

N

63
64
65

25
27

36

52
58

24
34

57

48

26

55

67
66

69 70
71

68 72
73

31

32

29
30

74

77

78
79

75

84

80 81
82

86
87
88

83
90

2000

0

2000

4000 Feet

Legend85

7689

Surveyed Zones
Polashi Zone
Tejgaon Zone
Baridhara Zone
Mohammadpur Zone
Siddique Bazar Zone
Mirpur Zone
Postagola Zone
Khilgaon Zone
Rail line
Water body
Ward Boundary

Map 1: Study Area in Dhaka city

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ICUS Report 54

For covering the all details, fire fighting equipments are divided into four parts i.e. firefighting and fire protection system which includes water-based system and dry system,
precautionary arrangement, detection and alarm system , and evacuation, rescue andsalvation system. All of these four parts comprise of several components.
4.1 Evaluation of fire fighting and protection system
Fire fighting and fire protection system consists two sub-system i.e. water –based systemand dry system. Water-based system of fire fighting and fire protection include availability ofstandpipe and hose system, sprinkler system, water supply sources to standpipe, capacity ofunderground and roof gravity tank, details of fire pump and jockey pump, and availability ofSiamese connection. Buildings should have underground reservoir of 50000 gallons andoverhead reservoir of 25000 gallons (BNBC, 2003). But from the survey has shown that74% and 96 % of total buildings are undersized for underground and overhead reservoir
respectively. From questionnaire survey it has been found that out of 53 buildings, 24 havestandpipe connection but not all of them were in work. After a detail investigation aboutstandpipe which includes number, diameters of standpipe, class of standpipe (class I, class II,class III), only 7 buildings reflected a good condition whereas 15 buildings showed very bad
condition. Among 24 buildings having standpipe, only 10 buildings have fire pumps andonly 5 of these are in good condition i.e. number and pressure of pump are adequate. Only 2commercial buildings have water sprinkler system. But in BNBC (2003), sprinklers, hosereel and hose pipe are strongly recommended to install in high-rise buildings as safetymeasure. Photograph 4, 5 and 6 show fire pump, jockey pump and hose reel with standpipe
in a commercial building respectively.

Photograph 4: Fire pumpin commercial building

Photograph 5: Jockey
pump in commercial
building

Photograph 6: Hose reel withstand pipe in commercial
building
27

March 2011

Dry system includes fire lift and portable fire extinguisher in floor and basement. Fire
extinguisher system with combination of carbon-dioxide extinguisher, dry chemical
extinguisher is available in 53% buildings. However, it has been observed that most of thebuildings’ fire extinguishers are not in required quantity and they are out of date. As thesurveyed buildings are high rise structures, it is mandatory to set up fire extinguisher system
to control the fire incidents initially. Most of the buildings have no hose pipe or hose reelsystem.

Extinguisher

Hose reel

Photograph 7: Blocked hose pipe

Photograph 8: Perfect position ofhose reel with fire extinguisher

4.2 Evaluation of precautionary arrangements
Precautionary arrangement is very important for minimizing the loss of lives and properties.
It comprises heat and smoke vent, four hours rated door of substation and 2 hours rated wallof substation. From the questionnaire survey it has found that only 10 buildings have 4 hours
rated door and 2 hours rated wall of substation. Number of building having smoke and heatvent is only one.
4.3 Evaluation of fire detection and alarm system
Detection and alarm system includes availability of fire alarm (automatic or manual), smokeand heat detector, Public Address (P.A.) system and existence of emergency light in staircase and corridor. Among the studied buildings none of them have flame detector. On theother hand, it has been observed that 25% buildings and only 4% buildings have smoke
detector and heat detector respectively. In addition, 36% buildings have alarm system andamong them 30% have public address (PA) system (see Figure 6).
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Figure 6: Overall scenario of fire fighting system in Dhaka City
From observation, it is evident that fire fighting detectors and equipments are seldom tested
and checked as routine work.

Photograph 9: Fire alarm and firebell

Photograph 10: Smoke detector

4.4 Evaluation of evacuation, rescue and salvation system
Evacuation, rescue and salvation system consists of total number of stair and emergency
staircase, width of normal and emergency stair, availability of fire refuge area, trained
personnel, width of front road, evacuation plan of the inmates of the buildings and practiceof fire drill. According to Bangladesh Fire Service and Civil Defense (BFSCD), Minimum
width of frontal road should be 30 ft for free moving of fire vehicle. Survey shows that a
considerably large number of buildings i.e. 27.5% of surveyed building have inadequate
width of approach road (less than 30ft) for fire engines to reach the building (see Figure 7).
29

March 2011

Figure 7: Width of approach road
More than 49% buildings don’t have any emergency exit stair. In addition, exit signals forescape route are provided improperly and inadequately which poses a threat to theevacuation. In most of the cases escape routes remain blocked (see Photograph- 11 and 12).

1.5 feet

Photograph 11: Narrow
emergency stair case in a
residential building

30

Photograph 12: Blocked emergency stair case in acommercial building

BNUS Annual Report-2010

ICUS Report 54

Among all the surveyed buildings, only 11 buildings have trained personnel and only 16
buildings which include garments and commercial building perform fire drill regularly. Most
surveyed garments workers were trained by Bangladesh Garment Manufacturers andExporters Association (BGMEA). Usually they provide lectures, taken exam and lastly done
evacuation drill in the premises of garments. In the surveyed commercial buildings whichhave trained personnel got training related to operation of hose reel and fire extinguisher andevacuation drill from Bangladesh Fire Service and Civil Defense (BFSCD). Mainly security
guard and few care takers of the building have this training. The respondents were asked
about their evacuation plan during the fire incidence but only few people have theirevacuation plan. Evacuation plan consists use of fire fighting equipment what they have,escape from the building through emergency exit and taking shelter in ground floor or any
available open space adjacent to the building.
5. SCORING OF THE SURVEYED BUILDINGSOne of the main purposes of this study was to provide score to the surveyed building basedon their existing fire fighting equipments. For providing score, data collected from fieldsurvey were compared to the provision of Bangladesh National Building Code (BNBC) andthat of Bangladesh Fire Service and Civil Defense (BFSCD). 0-10 scale was selected toprovide an initial rank to the different components of fire fighting equipments. Then fromcase studies and experts opinion, weights were assigned to each of the four parts offirefighting equipment. The process of obtaining the score is given below:
Total Score (TS) = weight for water-based system *(acquired number in scale of 0-10) +weight for dry system *(acquired number in scale of 0-10) + weight for precautionary
arrangement *(acquired number in scale of 0-10) + weight for detection and alarm system*(acquired number in scale of 0-10) + weight for evacuation, rescue and salvation system*(acquired number in scale of 0-10).
Experts have assigned 12 for water-based system, 8 for dry system, 25 for precautionary
arrangement, 30 for detection and alarm system and 25 for evacuation, rescue and alarmsystem.
For evaluating the condition of Buildings, all buildings are divided into 5 category based on
their in-built fire fighting system. These categories are given below,

31March 2011

Table1: Building Condition Based on Total Score
Building Condition

Total Score(TS)Low

Below 20

Moderately Low

21-40

Moderate

41-60

Moderately High

61-75

High

75-100Figure 8: Quantitative diagram of present condition of building at Dhaka city
The pie chart portrays that most of the buildings (62%) are in lack of in-built fire fighting
equipments whereas the number of buildings which are highly equipped with in-built firefighting system are significantly low.
6. CONCLUSION
After analyzing a considerable amount of data in Dhaka city, it can be said that the overall
condition of buildings very vulnerable to fire fighting. Only little number of buildings showsmoderate to good condition. Though this study has not been conducted with a wide range ofdata, it represents the miserable condition of Dhaka city to fire hazards. For improving thecondition, all buildings should follow the provision provided by Bangladesh National
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BNUS Annual Report-2010

ICUS Report 54

Building Code and Bangladesh Fire Service and Civil Defense during construction ofbuilding. To ensure that, authority should be very strict and should take action against thoseviolating the concerned laws. The related building codes of different countries need to bestudied thoroughly and adopted according to Bangladesh’s context. In addition to law
enforcement, to create public awareness, different workshop can be arranged. Electronic andprinting media can play an important role for increasing awareness. A pragmatic fire safety
plan can be made for all the buildings with the help of the fire department.
REFERENCES
1. Bangladesh National Building Code (BNBC), 2003
2. Bangladesh Fire Service and Civil Defense (BFSCD)
3. The Daily Star (www.thedaily star.net) accessed on June 2, 2010.
4. The New Age (2004) accessed on June 2, 2010.

33

PART-III

MICROTREMOR H/V TECHNIQUE FOR SITERESPONSE ANALYSISBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Saidur Rahman
Mehedi Ahmed Ansary

ICUS Report 54

1.1 INTRODUCTION
In the recent past, Bangladesh has not suffered any damaging large earthquakes, but in thepast few hundred years, several large catastrophic earthquakes struck this area. So far, all the
major recent earthquakes have occurred away from major cities, and have affected relatively
sparsely populated areas. In 1897, an earthquake of magnitude 8.7 caused serious damages
to buildings in the northeastern part of India (including Bangladesh) and 1542 people were
killed. Recently, Bilham et al. [1] pointed out that there is high possibility that a huge
earthquake will occur around the Himalayan region based on the difference between energy
accumulation in this region and historical earthquake occurrence. The population increasearound this region is at least 50 times than the population of 1897 and city like Dhaka has
population exceeding several millions. It is a cause for great concern that the next greatearthquake may occur in this region at any time.
The infrequent occurrence of destructive earthquakes does not permit the compilation ofenough data to support the estimation of the distribution of damages in the future. To
overcome this lacking, different authors proposed the use of alternative sources of excitation,such as, distant earthquakes, small near earthquakes, explosions, aftershocks andmicrotremors. The use of microtremor, an idea pioneered by Kanai et al. [2] turns into one of
the most appealing approaches in the site effects studies, due to its relatively low economic
cost, and the possibility of recordings without strict spatial or time restrictions (Rodriguez
and Midorikawa [3]). The H/V spectral ratio technique of microtremors gained popularity inthe early nineties, after the publication of several papers (Nakamura [4]; Field and Jacob [5];Lermo and Chávez-García [6]) claiming the ability of this technique to estimate the site
response of soft sedimentary deposits satisfactorily. This method is rather attractive indeveloping countries characterized by a moderate seismicity, where only very limited
resources are available for seismic hazard studies. The H/V spectral ratio determined frommicrotremors has shown a clear peak that is well correlated with the fundamental resonancefrequency at “soft” soil sites (Bard [7]; Horike et al. [8]; Field et al. [10]; Lachet and Bard[9]: Lermo and Chávez-García [11]). Comparison of microtremor and earthquake spectral
ratios at strong-motion instrument sites across SW British Columbia showed similar
fundamental periods and in greater Victoria remarkably similar amplitudes, validating theuse of the method for linear earthquake site response Molnar et al. [12].
Ohmachi et al. [13] and Lermo and Chávez-García [6] applied the H/V ratio method toanalyze microtremor measurements. Lermo and Chávez-García [11] used it to assess theempirical function of the S-wave, part of an earthquake record, obtained from three cities in35

March 2011

Mexico. Their results clearly indicated that the H/V ratio could provide a robust estimate of
frequency and amplitude of the first resonant mode, albeit not of the higher modes. In themeantime, Field and Jacob [5] and Field et al. [10] considered the response of sedimentarylayers to ambient seismic noise and claimed that the H/V ratio method was an effective andreliable tool to identify the fundamental resonance frequencies of all layered sedimentarybasin. Further evidence was given by Suzuki et al. [14] who used both microtremor andstrong-motion data in Hokkaido, Japan, and ascertained that the peak frequency determinedby the H/V ratio seemed to correspond with the predominant frequency estimated from thethickness of an alluvial layer. Based on numerical calculations, many other researchers(Lermo and Chávez-García [11], 1994; Lachet and Bard [9]; Dravinski et al. [15] haveshown that the H/V ratio method is obviously able to predict fundamental resonant
frequency well. Huang et al. [16] found that the ground vulnerability index (Kg) values in
the liquefied areas were higher than those in the neighboring areas without liquefaction at 42
points in central Taiwan. This study shows supporting evidence for the first time that the
H/V ratios of microtremor can be a good alternative indicator for an area’s potential forliquefaction. Site amplification characteristics can be evaluated by one-point two-component
surface recordings of earthquake ground motion, in a similar manner as proposed byNakamura for microtremor Ansary et al [17].
Although it is not possible to prevent such calamities, it is however, possible to mitigate theimpacts of this disaster. Specific roles and responsibilities relating to earthquake hazard
should be emphasized in our disaster mitigation plan. Bangladesh is a country characterized
by a moderate seismicity with almost no resources is available for large scale seismic hazard
studies. The objective of this study is to evaluate the site response using H/V spectral ratio of
microtremors in terms of predominant frequency and corresponding amplification within
Dhaka city area.
1.2 STUDY AREA:
Microtremor measurement has been carried out in 132 locations in the Dhaka city (SeeFigure 1). Figure 2 shows the Google map of the study area.

36

BNUS Annual Report-2010

ICUS Report 54

Figure 1: GIS map of 132 Microtremor observation points of the study area

New Academic
Building atwest Polashi

Civil
Engineering
Building

Figure 2: Google Map of study area
1.3 MICROTREMOR OBSERVATION
There are several small amplitude vibrations that appear in a nearby surface ground. The
frequency range of such vibrations is from 0.1 to 10 s. Vibrations that do not last long, lessthan 1 s, are currently called microtremors or Kanai’s microtremors Seo [18] and those thatlast longer are called microseisms Taga [19]. Microtremors are probably caused by vehiculartraffic, heavy machinery, household appliances and other sources that are not related toearthquakes; however, there are small waves propagated from artificial sources associated to37

March 2011

daily life. Kanai et al. [2] originally introduced a theoretical interpretation and practicalengineering application of microtremors that is especially convenient, easy and cheap forevaluating surface ground frequency properties.

Group photo of team work

Microtremor Data Recording

Microtremor Data Recording

at Residential Hall of BUET

at West Polasi of BUET

(3:00 AM)

(4:00 PM)

Figure 3: Microtremor data recording for site response analysis
This has many engineering applications, for example, soil type classification of soil layers,
prediction of ground shear wave velocity and the evaluation of the predominant periods ofsoil layers during earthquake tremors. Microtremor measurements within the Dhaka city
have been performed in the winter of 2011. After being integrated and amplified, the signal
proportional to displacement have been recorded directly on a lap-top computer (See Figure3). Microtremors have been recorded at 132 sites with a 40m x 40m dimension grid. Eachobservation time was 120 s and the signal was sampled every 0.01 seconds. In addition,
Most of the measurements were carried out from 12:00 PM to 5:30 AM in order to minimize
artificial noises due to traffic and human activities. Several windows were selected fromthese records, for the analysis. The criterion for selecting time histories was visual (SeeFigure 4). Time histories that consisted noise were excluded from calculation. As
microtremors spectra could be more or less influenced by close sources, Fourier spectra havebeen calculated at each point for one or several parts of the vertical and the horizontal
components records where there was no artificial disturbance. Consequently, special care has
been taken to avoid disturbances caused by machinery, traffic or by pedestrians passing near
the instrument during microtremor measurements, because such kinds of noise are transientand do not show the stationary characteristics of ground vibrations Yamanaka et al [20].
Therefore this part of the record has been removed from the analysis or in the worst cases the
38

BNUS Annual Report-2010

ICUS Report 54

measurement has repeated at the same point in more favorable conditions. In order to checkthe stationarity of microtremor measurements, continuous measurements have been made for24 hours at thirteen sites with different soil conditions (See Figure 6). These sites are locatedin the West Polasi of BUET campus.

Figure 4: Field Time History Data recording from 1 to 20.48seconds using microtremor
at MT 01 observation point (During 02:28 AM on the 14th February, 2011)
1.4 OUTLINE OF METHODOLOGY
The amplitude ratio (H/V) of horizontal to vertical spectra has become popular to determine
predominant period and amplification of a site. It is well known that, degree of damage
during earthquakes strongly depends on dynamic characteristics of buildings as well as
amplification of seismic waves. Among the other time consuming and expensive approaches,
microtremor is the easiest and cheapest way to understand the dynamic characteristics of soil
as well as structural element. In a short period of time it provides several information
including natural frequency, amplification and vibration characteristics of soil and structure
at different frequencies.
Following steps have been followed in this study:
A. Microtremor Analysis:
Microtremors data recording have been carried out in a selected location of Dhaka city. Each
record comprises of three components, viz., EW, NS and UD. For spectral analysis threenoise-free portions of 20.48s of the recordings have been taken at 100 Hz instrumental
39

March 2011

sampling (See Figure 5). For the checking of stability of soil response using microtremor ateach point of sensor location microtremor data recording have been executed at different
time of the day (See Figure 6).
Time domain data is not suitable for the clear identification of soil response due to ambient
noise. This is why First Fourier Transformation (FFT) have been applied on the time domain
records. After smoothing the corresponding spectra, spectral ratio (H/V) technique have been
applied to derive transfer functions. The applied sequences are given:
1. FFT Transformation: At first, Fourier spectra of the two horizontal directions (EastWest and North-South) and the vertical component (Up-Down) have been calculated.
2. Smoothing of the Spectra: After Fast Fourier transformation (FFT), the combined
horizontal and vertical spectra have been digitally filtered applying a logarithmic
window) with a suitable bandwidth coefficient. This filtering technique has been applied
to reduce the distortion of peak amplitudes.
3. Calculation of the Soil Response functions: The smoothed combined horizontal
spectrum have been divided with the smoothed vertical component to plot Horizontal tovertical spectral ratio (H/V) which provided the desired predominant frequency andcorresponding amplification factor of the investigated portions (20.48 s) of records.
4. Estimation of Predominant period and Amplification: After calculating three sets ofthe H/V ratios at selected grid, they have been normalized to obtain a relatively nonbiased site specific H/V ratio. Then, Normalized H/V ratios at different time of the day
have been plotted in Logarithmic window. From this normalized H/V ratio thepredominant frequency and corresponding amplification factor of this site have beentaken.
The analysis result of predominant frequency and Horizontal to Vertical spectral ratio (H/V)
along East-West and North – South direction has been shown in Table 1.

40

BNUS Annual Report-2010

Maximum velocity amplitude = 7.5 µm/sec

5

Maximum
5 velocity amplitude
10 = 7.5 µm/sec 15-5Time (Sec)

-10

-15
0

10

10

10

15

Time (Sec)

-1

10

-2

10

-3

EW.1
EW.2
EW.3
AVRAGE

0

10
5

1

10

0

-3

10

15

-15
0

5

10

-5 Velocity amplitude = 8 µm/sec
Maximum

5

NS.1
NS.2
NS.3
AVERAGE

-15
15

20

0

1

10

-2

20

-15

0

-5

5

10

10

15

Time (Sec)

20

1

UD.1
UD.2
UD.3
AVERAGE

-10

10

-15
1

10
5

NS.1 10
NS.2
Time (Sec)NS.3
AVERAGE

15

0

20

10

0

1
105

10

15

UD.1 Time (Sec)
UD.2
UD.3
AVERAGE

20

-1

10

Velocity Time History along three directions (MT_113)
10

-1

15

Time (Sec)

-10

0

20

Time (Sec)1-10

EW.1 10
EW.2Time (Sec)EW.3
AVRAGE

10

0.1

1

-1

10

0

10

NS.1
-2
-1
NS.2 10 10
NS.3
AVERAGE

0

10

-2

-3 10

10

0.1

10

Frequency (Hz)
10

10

10

Velocity Time History along three directions (MT_113)

-1

-2

5

0

1

-10

UP-DOWN (Time0History)

Amplitude spectrum (µm)

10

0

10

0

0

10

-15

20
-5

EW.1
EW.2
EW.3
AVRAGE

Fourier amplitude (µm)

Fourier amplitude (µm)

10

-10

0

-3

Amplitude spectrum (µm)

10

-15

5

1

-10

20

Time (Sec)

Velocity spectrum (µm)

1015Maximum Velocity amplitude = 8 µm/sec-55Velocity Time History along three directions (MT_113)

0-5

Maximum= 7 (µm/sec)
0-5 Velocity amplitude
5
10

5

Velocity (µm/sec)

5

-15

10

20

15

0

1

Frequency (Hz)

-1

10

-3

10

10

1

10

0

Amplitude spectrum (µm)

05NORTH - SOUTH (Time History)

0

Velocity spectrum (µm)

10 -15

Maximum Velocity amplitude = 7 (µm/sec)-5

0 UP-DOWN (Time History)

10

-10

15

EAST - WEST (Time History)

15

NORTH - SOUTH (Time History)

10

Velocity (µm/sec)

Velocity (µm/sec)

-5

15

0

Maximum Velocity amplitude = 8 µm/sec

5

Velocity (µm/sec)

EAST - WEST (Time History)

10

-10

Velocity (µm/sec)

15

0

5

ICUS Report 54

UP-DOWN (Time History)

10

Maximum Velocity amplitude = 7 (µm/sec)

Velocity spectrum (µm)

Velocity (µm/sec)

5

15

Velocity (µm/sec)

10

Maximum velocity amplitude = 7.5 µm/sec

15

NORTH - SOUTH (Time History)

Velocity (µm/sec)

10

Fourier amplitude (µm)

15EAST - WEST (Time History)

Velocity (µm/sec)

15

UD.1
UD.2
UD.3
AVERAGE

10

0

-2

10

-1

10

-2

10

-3

10

10

0.1

1

10

Frequency (Hz)

-1

10

-3

10

Three segments of Fourier amplitude and their average value along three directions (East-West,
0.1

1Frequency (Hz)

0.1

10

1

Frequency (Hz)

-2

10

0.1

10

1

10

Frequency (Hz)-2

10

Three segments of FourierNorth
amplitude
andandtheirUpaveragevalue
along three directions (East-West,- South- Down)(MT_113)-3

10

North - South and Up - Down) (MT_113)

-3

10
0.1
20

1

EW1
EW2
EW3
AVERAGE
20

10

10Frequency (Hz)

0.1

20
10

NS1
NS2
NS3
AVERAGE

20

1

10

0.1

20

Frequency (Hz)1

10Frequency(Hz)
EAST - WESTNORTH - SOUTH

10

20

Three segments of Fourier amplitude and their average value along three directions (East-West,1

0.1

Frequency (Hz)

0.1

0.1
0.1

1

10

Frequency (Hz)20

H/V Ratio

H/V Ratio

0.1

10 1

Frequency (Hz)1

H/V Ratio

10

0.1

0.1

1

NS1
NS2
NS3
AVERAGE

10

0.1
0.1

10

1

0.1

1
Frequency
(Hz)

10

1

0.1

0.1

10 1

Frequency (Hz)1

EAST - WESTNORTH - SOUTH

1

H/V Ratio

0.1

0.1

H/VSpectral
Spectral Ratio
H/V
Ratio(MT_113)(MT_113)

0.1

1

0.1

1

1

10

Frequency (Hz)Frequency (Hz)

10

0.1

10

0.1

Frequency (Hz)1

10Frequency (Hz)Figure5:Processed
Processedgraphsofpoint
Spectralgraphs
Ratio (MT_113)
Figure
5:H/V
of MT
MT113
113observation
observation
point
0

-3

10
-2

0.1

1

Frequency (Hz)

-3

10

-1

10

-2

-1

0

10

-1

10

10

10

-2

10

10

-3

0.1

1

Frequency (Hz)

-3

10

-1

10

-2

00:27 AM (UD)
17:15 PM (UD)00:56 AM (UD)AVERAGE (UD)00:27 AM (UD)00:56 AM (UD)AVERAGE (UD)10

-1

15:12 PM (UD)
17:15 PM (UD)00:27 AM (UD)00:56 AM (UD)AVERAGE (UD)-2

Fourier amplitude (µm)

1010Fourier amplitude (µm)

Fourier amplitude (µm)

-2

10

-2

10

0

15:12 PM10
(NS)
17:15 PM (NS)00:27 AM (NS)00:56 AM (NS)AVERAGE (NS)

17:15 PM (EW)
00:27 AM (EW)
00:56 AM (EW)AVERAGE (EW)

-1

10

0

10

10 15:12 PM (EW)10

15:12 PM (UD)1017:15 PM (UD)15:12 PM (UD)15:12
00:27PMAM (NS)(NS)
17:15
00:56PMAM (NS)(NS)AVERAGE(NS)
00:27
AM (NS)
00:56 AM (NS)AVERAGE (NS)Figure 5: Processed graphs of MT 113 observation point-1

10

Fourier amplitude (µm)

Fourier amplitude (µm)-110

15:12 PM (NS)
17:15 PM (NS)010

15:12 PM (EW)
00:27 AM (EW)
17:15 PM (EW)
00:56 AM (EW)AVERAGE (EW)
00:27 AM (EW)
00:56 AM (EW)AVERAGE (EW)

Fourier amplitude (µm)

Fourier amplitude (µm)
0

10

0

10

15:12 PM (EW)
17:15 PM (EW)0

10Fourier amplitude (µm)

010Fourier amplitude (µm)

1

20

1

H/V Ratio

H/V Ratio

H/V Ratio
10

EW1
EW2
EW3
AVERAGEEAST - WESTNORTH - SOUTH

10

North - South and Up - Down) (MT_113)
120

H/V Ratio

NS1
NS2
NS3
AVERAGE

10

H/V Ratio

EW1
EW2
EW3
AVERAGE

10

10

10

10

10

-1

10

-2

10

-3

-2

-3

0.1

1

10

Frequency (Hz)0.1

1(Hz) andFrequency
Frequency (Hz) at four different times along
Fourier amplitude
three(Hz)directions (East-West, NorthFrequency- South

0.1

1

10

0.1

1

10

10

-3

10

Up - Down)(MT_16)
Fourier amplitude at four different times
along three
directions (East-West, North - South and
-3

10

0.1

1

Frequency (Hz)

10

10

-3

0.1

1

Frequency (Hz)

10

0.1

1

10

Frequency (Hz)Fourier amplitude at four different times along
directions(East-West, North - South andUp -three
Down)(MT_16)Up - Down) (MT_16)

41March 2011

11

1

1

0.1

0.1

0.1 0.1
0.1

11 (Hz)
Frequency

10

Frequency (Hz)

0.1

10

(Hz)
H/V Ratio at Frequency
different
time
0.1

1

10

(MT_16) direction
along East-West(MT_16)20

15:12 PM(NS)AVERAGE(NS)
00:56 AM (NS)
17:15 PM (NS)AVERAGE (NS)00:27 AM (NS)00:56 AM (NS)10
AVERAGE (NS)0.1 0.1

20

EAST - WESTNORTH - SOUTH

10

1

1

1

0.1

EAST - WESTNORTH - SOUTH

EAST - WESTNORTH - SOUTH
10

10

1

0.1

H/V Ratio at different timealongRatio
East-West
direction
H/V
at different
time
along
East-West
direction

20

15:12 PM (NS)
17:15 PM (NS)15:12 PM (NS)00:27 AM (NS)

17:15 PM (NS)00:56 AM (NS)1020 AM (NS)
00:27

H/V Ratio
H/V Ratio

10

H/V Ratio

10

20

H/V Ratio

10

H/V Ratio
H/V Ratio
H/V Ratio20

15:12 PM (EW)
17:15 PM (EW)
15:12AMPM (EW)(EW)
00:27
17:15AMPM (EW)
(EW)
00:56
00:27
AMPM
(EW)
15:12
(EW)
AVERAGE
(EW)
00:56
AMPM
(EW)
17:15
(EW)
AVERAGE (EW)
00:27 AM (EW)
00:56 AM (EW)AVERAGE (EW)

20

1020

H/V Ratio
H/V Ratio

20

1

0.1

10

Frequency (Hz) 1

0.1

10

Frequency (Hz)Frequency (Hz)H/V Ratio at different
time
0.1

1

0.1
0.1

1

Frequency (Hz)

0.1

10

1

Frequency (Hz)Frequency (Hz)H/V Ratio along East-West

1

10

0.1

1

10

10

H/V Ratio at different time
H/V Ratio along East-West
along
North
–
South
and
North
– SouthH/V
Ratio
at different
H/V
Ratio–(MT_16)
along
along
North
– Southtime
and
North
SouthEast-West(MT_16)
direction
along (MT_16)
North – Southand North – South (MT_16)
direction (MT_16)(MT_16)
direction (MT_16)
Figure 6: Stability checkof soil response at different time at MT 16 observation point
Table 1: Microtremor Data Analysis
Figure 6: Stability checkTableof soilat different
time at MT 16 observation point
1:response
Microtremor
Data Analysis
Figure 6: Stability check of soil response at different time at MT 16 observation point
ID

PredominantID
ID

PredominantFrequency
(FF)

1
3

1
5
31
7
53
9
75

11

7
913
119
15

11
13
17
13
19
15
15
21
17
23
17
19
25
19
21
27
21
23
29

23
25
31
25
27

42

NS

1.50
EW

2.25NS22.70 NS

2.25

4

6.50
2.30 2.002.25

6

1.6
NS

0.98
EW

0.97
NS

0.75
1.50

0.80
1.6

1.50

0.98
1.35
0.98
0.75

1.6

2.30
EW

3.00EW

2.30

0.75
1.35
0.70
1.35
1.30
0.70
1.30
0.70
1.02

0.97
3.00
2.70
1.35
2.00
2.00
0.97
3.00
2.70
0.80
6.50
2.00
1.20
1.90
1.80
0.80
6.50
2.00
1.35
2.00
2.00
0.85
2.50
1.90
1.35
2.00
2.00
1.20
1.90
0.50
2.20
1.851.80
1.20
1.90
1.80
0.85
2.50
1.90

1.01
0.35

0.98
0.40

1.30

0.70
0.70
0.35
0.70
0.98
1.02
1.02
0.70
0.35
0.98
1.35
0.98
0.70
2.30
0.70
1.01
1.40

33

31
33
33
35
35

0.30
1.80
1.80
0.50
0.50

1.80

2.30
1.40
0.50
1.40
0.30

1.15

0.85
0.50
0.40
0.50
0.85
1.15
1.15
1.35
0.40

H/V Ratio(FF)
EW Frequency
NS
EW

8
10

1.00 EW0.80

NS2.250.70 EW0.65
2.70
NS
2
1.00
0.80
0.90 1.00
0.90 0.80
3.00
42
0.70
0.65
1.30 0.70
1.25 0.65
3.50
64
0.90
0.90
0.55

0.50

1.70

0.90
0.90
86
1.30
1.25
12
0.80
0.90
2.45
8
1.30
1.25
10
0.55
0.50
14
0.45
0.43
5.00
10
0.55
0.50
3.00
2.05
16 12 0.98 0.801.45 0.902.50
2.50
1.90
12
0.80
0.90
2.20 1.701.85 18 141.80
0.90 0.450.95 0.433.00
2.20
1.85
14
0.45
0.43
2.20
3.00 1.952.05 20 16 0.65 0.980.60 1.452.00
3.00 3.001.70
2.05 22 18
16 0.70 0.90
0.98
1.45
4.00
1.00 0.95
2.50
1.80
2.00
0.90 0.95
3.00
1.80 2.301.95
1.70 24 20
18 0.80 0.65
0.90
2.20
0.60

0.85
0.90
0.85 3.502.20 2.501.95
1.35
4.00
3.00
2.40
1.90
1.90
1.35
4.00
3.00
0.98
2.00
2.30
0.80
4.00
2.50
0.98
2.00
2.30
0.90
3.50
2.50
0.30
1.00
1.20
0.90
3.50
2.50
2.40
1.90
1.90
1.80

PredominantID

PredominantFrequency(FF)
Frequency(FF) EW
EW
NS

1.01
1.35
0.30
1.35
2.30

27
29
35
29
31

H/V Ratio

Table
Microtremor
Analysis
H/V1:Ratio
IDDataPredominantFrequency(FF)
H/V RatioID
PredominantFrequency (FF)

2.30

1.90

26

1.40 0.60
3.50
20 1.45 0.65
22
0.70
1.00
28 22 2.50 0.70
2.50 1.00
2.00
24
0.80
0.90
30
1.50
1.50
2.50
24
0.80
0.90
26
1.45
1.40
32

26

4.00

5.00

1.45

1.90

1.40

34 28 1.30 2.501.25 2.503.00

2.40
1.90
1.90
28
2.50
0.80 2.00
4.00 4.502.50 36 30 0.35 1.500.36
0.40
0.80
4.00
2.50
30
1.50
0.30
1.00
1.20
32
4.00
0.30
1.00
1.20
32
4.00
1.80
2.30
1.90
34
1.30
1.80
2.30
1.90
34
1.30
0.40
2.00
4.50
36
0.35
0.40
2.00
4.50
36
0.35

2.50
1.504.50
1.50
5.00
5.00
1.25
1.25
0.36
0.36

H/V Ratio
H/V Ratio
NS
2.50
EW
2.30
EW
2.25
2.00
2.25
2.70

2.50
2.70
3.00
1.40
3.00
3.50
2.40

3.50
1.70
2.10
1.70
2.45

NS
NS
2.50
2.50
2.30
2.30
2.00
2.00
2.50

1.80

2.50
1.40
1.40
2.40

2.00
3.00
2.00
3.00
2.00
2.50
1.90
2.50
3.00

2.75
1.75
1.75
2.00
2.00
2.00

2.45
5.00
2.75
5.00
1.75
2.50
2.50
2.00
3.00

2.40

3.00
3.50
2.50
3.50
2.00

2.40
2.10
2.10
1.80
1.80
2.75

1.25

2.00
3.00
3.00
1.90

1.90
3.00
3.00
4.50
4.50

2.50
1.25
1.25
3.20
3.20

2.00
2.50
3.20
2.50
1.90

1.90
2.40
2.40
2.50

BNUS Annual Report-2010

ICUS Report 54

ID

Predominant

H/V RatioID

Frequency (FF)

Predominant

H/V Ratio

Frequency (FF)

EW

NS

EW

NS

EW

NS

EW

NS

37

0.35

0.70

3.00

2.00

38

1.35

1.35

2.20

2.20

39

1.35

1.32

6.00

3.00

40

1.25

0.98

3.00

1.50

41

0.65

0.70

1.65

2.20

42

0.35

0.35

2.05

2.50

43

1.35

1.55

2.90

2.80

44

1.40

1.45

2.50

2.03

45

0.98

1.35

2.30

2.25

46

1.30

1.35

2.20

1.95

47

0.75

0.70

1.70

1.12

48

1.30

0.80

3.00

2.80

49

1.30

1.50

2.25

3.00

50

1.40

1.36

1.90

1.85

51

1.35

0.70

2.24

2.20

52

1.20

0.50

2.00

2.50

53

1.30

0.90

3.50

3.00

54

0.80

1.50

2.20

2.10

55

3.00

3.00

2.00

2.05

56

0.50

0.40

2.50

2.20

57

0.50

0.50

1.25

0.90

58

1.70

1.70

1.80

2.00

59

1.35

1.50

3.50

1.50

60

1.35

1.38

4.0

2.5

61

0.98

0.90

1.70

1.60

62

0.45

0.40

8.00

4.50

63

1.35

1.32

4.20

2.00

64

1.40

1.45

2.40

2.38

65

1.30

1.35

1.80

1.75

66

1.55

1.50

2.05

1.90

67

2.50

2.45

1.50

2.00

68

2.05

2.08

1.30

1.25

69

2.00

3.00

1.50

1.30

70

5.00

5.10

1.85

1.95

71

1.50

0.75

1.95

2.70

72

1.35

1.35

2.50

2.45

73

2.90

3.00

1.80

1.75

74

1.35

1.40

1.50

2.00

75

5.00

5.00

1.70

1.60

76

4.50

4.00

1.70

1.50

77

2.40

2.60

1.50

1.60

78

0.45

0.40

1.65

1.60

79

0.90

0.75

2.20

2.50

80

0.40

0.40

1.50

1.45

81

1.03

1.02

2.20

1.75

82

1.30

3.00

1.50

1.10

83

0.50

0.40

3.05

2.10

84

0.35

0.40

5.00

3.50

85

0.90

1.10

2.40

2.05

86

0.35

0.37

1.85

1.15

87

0.80

0.77

2.30

2.25

88

0.70

0.90

3.50

3.05

89

1.40

1.30

2.50

2.00

90

1.35

0.50

1.70

1.90

91

1.80

1.90

1.60

1.55

92

0.70

0.85

2.30

3.05

93

0.70

0.80

2.70

2.10

94

2.50

4.50

1.40

2.00
43

March 2011

ID

Predominant

H/V RatioID

Frequency (FF)

Predominant

H/V Ratio

Frequency (FF)

EW

NS

EW

NS

EW

NS

EW

NS

95

1.75

1.80

2.00

2.50

96

4.50

4.00

2.05

2.40

97

4.10

4.05

1.70

2.50

98

1.40

1.25

2.70

2.05

99

0.70

0.70

2.00

2.10

100

7.00

7.10

1.50

1.70

101

0.85

0.90

3.50

3.40

102

1.40

1.15

2.50

2.45

103

0.50

0.50

5.50

4.50

104

2.50

2.70

1.50

1.70

105

0.50

0.30

2.10

1.03

106

1.40

1.45

2.20

2.30

107

1.35

1.40

2.25

2.30

108

2.50

2.40

1.00

1.05

109

0.40

0.50

6.00

3.50

110

1.40

1.50

2.50

2.45

111

1.30

0.85

4.50

2.75

112

1.35

1.00

3.50

2.50

113

1.10

1.00

2.05

2.15

114

1.25

1.10

2.50

2.00

115

1.40

0.85

3.10

2.40

116

1.20

1.10

2.10

1.50

117

5.50

5.50

1.90

1.70

118

1.40

1.30

2.95

2.10

119

1.30

0.95

2.85

2.10

120

1.50

0.50

3.50

2.50

121

1.25

1.35

4.00

2.05

122

1.30

1.15

2.50

2.00

123

2.50

3.00

2.15

1.55

124

4.00

4.20

1.40

1.50

125

4.50

4.45

2.20

3.00

126

2.50

2.45

1.50

1.45

127

6.00

6.50

2.10

2.05

128

1.05

2.50

1.60

1.50

129

1.10

3.15

1.50

1.95

130

1.40

1.10

2.05

1.75

131

3.00

3.05

1.75

2.00

132

1.25

1.10

2.60

2.15

CONCLUSIONS:
The results show that the ranges of predominant frequency ( ) in Bangladesh University ofEngineering and Technology (BUET) area are between 0.30 and 6.5 Hz. The maximum andthe minimum Predominant frequency have been found in MT 31 (East – West) and MT 127(North - South). In addition to this, Horizontal to Vertical spectral Ratio (H/V) ranges
between 1.0 and 6.5. The Maximum and the minimum H/V Ratio have been found in MT
MT 05 (East - West) and MT 108 (East - West). In some locations of the observation point
the H/V ratio obtained was very flat. In other locations the result was very clear predominantpeaks. For the stability analysis of microtremor thirteen selected points show that H/V ratios
are very stable. In general, the long period or low frequency zone corresponds to the soft soil
44

BNUS Annual Report-2010

ICUS Report 54

zone, with shorter period or high frequency in the hard and middle soil zones. In some places,
long periods or low frequency have been detected in the hard soil zone, this being due tolocal artificial deposits caused by compacting the soil. For details investigation SPT borelogs
and soil model are required to compare microtremor result.
REFERENCES:[1] Bilham, R., Gaur, V. K. and Molnar, P. (2001). Himalayan Seismic Hazard, SCIENCE,
293.
[2] Kanai, K. Tanaka, T. and Osada K. (1954). Measurements of Micro-tremors 1. Bulletin
Earthquake Research Institute, Tokyo University, 32, PP. 199-210.
[3] Rodriguez, V. S. H. and Midorikawa, S. (2002). Applicability of the H/V Spectral Ratioof Microtremors in Assessing Site Effects on Seismic Motion, Earthquake
Engineering and Structural Dynamics, 31, PP. 261-279.
[4] Nakamura, Y. (1989). A method for dynamic characteristics of sub-surface using
microtremor on the ground surface, Quick Report of Railway Technical ResearchInstitute, 30, PP. 25-33.
[5] Field, E. H. and Jacob, K. H. (1993). The Theoretical Response of Sedimentary Layers
to Ambient Seismic Noise, Geophysical Research Letter, 20, PP. 2925-2928.
[6] Lermo, J. and Chávez-García, F. J. (1994). Are Microtremors Useful in Site Response
Evaluation? Bulletin of Seismological Society of America, 84, PP. 1350-1364.
[7] Bard, P.Y. (2004). Effects of surface geology on ground motion: Recent results andremaining issues, Proceedings of the 10th European Conference on Earthquake
Engineering, Vienna, Austria, August 28-September 2, 1994, PP. 305-325.
[8] Horike, M., Zhao, B. and Kawase, H. (2001). Comparision of site response
characteristics inferred from microtremors and earthquakes shear waves. Bull. Seism.
Soc. Am, 81, PP. 1526-1536.
[9] Lachet, C. and Bard, P. Y. (1994). Numerical and theoretical investigations on thepossibilities and Limitations of Nakamura’s technique, J. Phys. Earth, 42, PP. 377-397.
[10] Field, E. H., Clement, A. C., Jacob, K. H., Aharonian, V., Hough, S.E., Friberg, P.A.,
Babaian, T.O., Karapetian, S. S., Hovanessian, M. and Abramian, H.A. (1995).
Earthquake site response study in Giumri (Formerly Leninakan), Armenia using
ambient noise observations. Bull. Seism. Soc. Am., 85, PP. 349-353.
[11] Lermo, J. and Chávez-García, F. J. (1993). Site effect evaluation using spectral ratioswith only one station. Bull. Seism. Soc. Am., 83, PP.1574-1594.
45

March 2011[12] Molnar, S., Cassidy, J. F., Monahan, P. A., Onur, T., Ventura, C. and Rosenberger, A.
(2007). Earthquake site response studies using microtremor measurements insouthwestern British Columbia, 9th Canadian Conference on Earthquake Engineering,
Ottawa, Ontario, Canada, 26-29 June, PP. 410-419.
[13] Ohmachi, T., Nakamura, Y. and Toshinawa, T. (1991). Ground motion Characteristics
in the San Francisco Bay area detected by microtremor measurements, Proc. 2nd. Int.
Conf. on Recent Advances in Geotech. Earth. Eng. & Soil Dyn., Saint Louis, Missouri,
11-15 March, PP. 1643-1648.
[14] Suzuki, T., Adachi, Y. and Tanaka, M. (1995). Application of Microtremor
measurements to the estimation of earthquake ground motions in the Kushiro cityduring the Kushiro-Oki earthquake of 15 January 1993, Earthquake Eng. Struc. Dyn.
24, PP. 595-613.
[15] Dravinski, M., Ding, G. and Wen, K. L. (1996). Analysis of spectral ratios for
estimating ground motion in deep basins, Bull. Seism. Soc. Am., 86, PP. 843-847.
[16] Huang, H. C. and Tseng, Y. S. (2002). Characteristics of soil liquefaction using H/V ofmicrotremors in Yuan-Lin area, Taiwan, TAO,Vol.13, No.3,325-338, September,
2002.
[17] Ansary, M. A., Yamazaki, F., and Katayama, T. (1996). Application of microtremor
measurements to the estimation of site amplification characteristics, Bulletin ofEarthquake Resistant Structure Research Center, IIS, University of Tokyo, No. 29, PP.
95-113.
[18] Seo, K. (1994). On the applicability of microtremors to engineering purpose,
Preliminary report of the Joint ESG Research on Microtremors after the 1993
Kushiro-Oki (Hokkaido, Japan) earthquake. Proc. of 10th European Conf. on Earthq.,
4, PP. 2643- 2648.
[19] Taga, N. (1993). Measurement of microtremors in Earthquake Ground Motion and
Ground Condition, edited by The Architectural Institute of Japan.
[20] Yamanaka, H., Takemura, M., Ishida, H. and Niwa, M. (1994): Characteristics of long
period microtremors and their applicability in exploration of deep sedimentary layers,
Bull. Seism. Soc. Am., 884, PP. 1831-1841.

46

BNUS Annual Report-2010

PART-IV

VULNERABILITY ASSESSMENT OF PUBLICBUILDINGS IN OLD TOWNBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Israt Jahan Sheuly, Sharmin Ara
Mehedi Ahmed Ansary

ICUS Report 54

1.

Introduction

Dhaka City Corporation (DCC) has 90 Wards in its jurisdiction. Old Dhaka is especiallycharacterized by high population density, poor structures and close proximity of buildings,
narrow road strips and earthquake vulnerability. To assess the earthquake vulnerability ofbuildings, Ward no. 68 of Old Dhaka is selected as the study area. It is very difficult andtime consuming task to assess the earthquake vulnerability of the existing buildings in any
study area. In this study the Rapid Visual Screening (RVS) method (FEMA-154, 2002) wasused to assess 1,383 buildings which covered 77 percent of the existing buildings in the
study area. Turkish Level-I and Level-II (Sucuoglu and Yazgan, 2003) a more detail analysisof the building was used to assess the structures proposed to be used as evacuation place.
The religious place like mosques, community center, educational institutes like schools,
colleges and other public places along with the open spaces like park, playground areconsidered as evacuation sites in this study. Four mosques, two schools and one community
center were analyzed in detail using Ferro-scanner which is a reinforcement detection
instrument with the help of Department of Civil Engineering, BUET.

2.

Existing Condition of the Building

The study area is highly vulnerable to earthquake due to its high density of population andpoor structural build up. Photograph 1 to 3 shows the existing condition of the study area.

Photograph 1: Unplanned urbanization- contiguous building character47

March 2011

Photograph 2:
Poor infrastructure - narrow road width in terms of building height, building density and also
population density.

Common wall

Common wall

Photograph 3:
The adjacency of building without any set back, serious pounding may occur during
earthquake48

BNUS Annual Report-2010

ICUS Report 54a) Type of Building Structure
At the first stage of urbanization and city development in our country, the capital city Dhaka
flourished from the older part. In the study area 39% buildings were found URM structure
which was very significant. 60% of the buildings were C3 structures. The number of C2
structure was very few (only eight) in this area because there were some recently constructed
7-8 storied structures with lift facility and shear wall. These three categories of buildings
were found in the site (see Figure 1).

Figure 1: Type of building structure in study area
Source: Field survey, 2009
Table 1: Type of building structures found in the study area
Building
identifier
C3(Moment
resistingframe)

PhotographCharacteristics and performance•

Usually masonry exposed in exterior.

•

Concrete columns and beams may befull wall thickness

49

March 2011•

Concrete shear wall buildings areusually cast in place.

•
C2(Concreteinch.
•

shear wallbuildings)

Shear wall thickness ranges from 6-10
These buildings generally performbetter than concrete frame buildings.

•

Damage commonly observed in tallerbuildings is caused by vertical
discontinuities and irregularconfigurations.

•

These buildings often use weak lime
mortar to bond the masonry unit
together.

URM•(Unreinforced
masonrybuildings)

Unreinforced masonry usually showsheader bricks in the wall surface.

•

The performance of this type of
construction is poor due to lack ofanchorage of walls to floors and roof,
soft mortar and narrow piers between
window openings.

b) Comparison of Buildings With Respect to ShapeThe configuration of building is very important for its performance during earthquake.
Buildings with irregular plans and elevation suffer much more damage compared tobuildings with regular shapes. Figure 2 shows that 72% buildings of the study area haverectangular plan i.e. the shape of the plan are rectangular and 28% buildings haveirregularity in their plan. It has also found from field survey that 25 % buildings arevertically irregular and 75% buildings are regular in their elevation shape (see Figure 3).
Buildings with irregular shape with respect to both plan and elevation shape tend to be more
vulnerable to earthquake (see Map 1 and Map 2).

50

BNUS Annual Report-2010

ICUS Report 54

Figure 2: Plan irregularities in buildings

Figure 3: Vertical irregularities in buildings

Source: Field survey, 2009

Source: Field survey, 2009

Photograph 4: Plan irregularity

Photograph 5: Vertical irregularity

51

March 2011

Map 1: Plan irregularities in building structure
Source: Field survey, 200952

BNUS Annual Report-2010

ICUS Report 54

Map 2: Vertical irregularities in building structure
Source: Field survey, 200953

March 2011c) Staircase Condition of the Residing Building
From household survey most of the respondents were found to consider the staircase
condition of their residing building to be ‘good’ but other part of the questionnaire showsmost of the buildings have very narrow width even less than or equal to 3 feet that is notfavorable in terms of evacuation from the building. Table 2 shows the existing width ofstaircase in the surveyed buildings.
Table 2: Staircase width of the surveyed buildings
Staircase Width (in feet)

Number ofbuildings

Less than or equal to 3

116

3 –5

46

5 –7

20

7 –9

10

9 – 11

3

11 – 13

3

No stair case (Semi-Pucca Building)

12

Total

210
Source- Field survey, 2009

Figure 4 shows a comparative study of the perception of the respondents about the conditionof the staircase in the building. It is seen from the figure that significant number of people
thinks the stair case of their buildings is ‘bad’ due to narrow width.

Figure 4: Staircase condition of residing building
Source: Field survey, 200954

BNUS Annual Report-2010

ICUS Report 54

3.

Vulnerability Assessment of Buildings

To propose an effective earthquake evacuation plan it is needed to assess the vulnerability ofexisting buildings. For the assessment of existing buildings vulnerability, two different
visual screening methods i.e. FEMA-RVS and Turkish Simple Survey (Level-I and Level-II)
procedure were applied. For the field survey of 77% of existing buildings the RVS method
was used while for detail evaluation of proposed evacuation shelter buildings Turkish Level
I and Level II Simple Survey method was used. Besides the building age, height, occupancy
and other relevant parameters were also analyzed to have a clear view of the locality. It isalready mentioned in Chapter 3 that the two storied buildings are more in number (22%)
followed by three storied buildings (19%) in the study area. As Old Dhaka is the ancient partof the Dhaka city, the number of URM structure (39%) is significant here. The construction
year of the buildings were also studied to get an overview about the existing condition ofbuildings in the study area. It helped in vulnerability assessment through focusing on thedeteriorated condition of the structures. In the study area 67% buildings age varied from 10
to 30 years and 11% buildings were more than 30 years old which made the area more
susceptible to earthquake damage. In the following sections the field survey data findings onearthquake vulnerability of the buildings are analyzed.
a) Buildings vulnerability assessment by RVS method
The earthquake vulnerability of the buildings is assessed using the Rapid Visual Screening(RVS) Method. Among 1,383 surveyed buildings, 1,375 buildings have been analyzed using
Rapid Visual Screening (RVS) method and rest structures are tin shed and semi pucca. The
score below which a structure is assumed to require further investigation is termed as “cutoff” score. It is suggested that buildings having a score less than the “cut-off” score should
be investigated by an experienced seismic design professional. If the obtained “final score”
is greater than the “cut-off” score the building should perform well in a seismic event. A
score of 1.5 and 2 are used in this study as two “cut-off” scores. RVS score ‘0’ is given to
the buildings that showed negative results, that means the buildings are in emergency needof detail evaluation by any structural engineer and take further actions like retrofitting, etc.
based on the result found.

55

March 2011

The Figure 5 shows that 54% buildings fall below the cut off value 2 according to FEMA
method and all of them require further detailed analysis on vulnerability to determine thelevel of actual risk (see Map 5).

Figure 5: Buildings according to RVS cut-off score 2
Source: Field Survey, 2009
Considering the economic condition of Bangladesh, 1.5 may be set as the cut-off score. In
this case 61% building fall in the safe region (see Figure 6 and Map 6) and they do not
require detail structural analysis.

Figure 6: Buildings according to RVS cut-off score 1.5
Source: Field Survey, 2009

Figure 7: Buildings classified on RVS score
Source: Field Survey, 200956

BNUS Annual Report-2010

ICUS Report 54

Map 3: Building vulnerability assessment through RVS score in the study area
Source: Field survey, 200957

March 2011

Map 4: Building vulnerability assessment through RVS cut off score 2
Source: Field survey, 200958

BNUS Annual Report-2010

ICUS Report 54

Map 5: Building vulnerability assessment through RVS cut off score 1.5
Source: Field survey, 200959

March 2011b) Assessment of public building to be proposed as evacuation shelter
Many features are considered in selecting evacuation place for the dwellers of this area.
Basically the Public buildings are selected on the basis of land use like mosque, school,
college, community center, meeting place etc. to be proposed as earthquake evacuation
shelters. Because the public places are accessible for all residents and usually it is located in
the central places within a targeted community group. The targeted area is highly dense andthere is a little number of open spaces. It is hard to reallocate and redevelop land andpropose for more open spaces due to high land prices and many other constraints. That’s
why along with the available open fields the public buildings are considered as shelter placewith necessary precautions to keep the building fit during earthquake.
In this study area 25 public buildings were selected as evacuation centers for the residents. A
more detail analysis using Turkish Level-I and Level-II method was done for the RCC (C3and C2) type buildings (21 in numbers in comparison with the RVS method). Turkishmethod is not applicable for URM buildings (4 public buildings in the area). It has beenfound from other studies that the Turkish method is more compatible in the circumstances ofour country. Besides the existing open spaces the following public buildings were selected to
be used as shelter and their vulnerability was assessed.
1. Islampur Jame Mosque

2. ShahjadaMia Jame Mosque

3. Jhubbu Khanam Jame Mosque

4. Jindabahar Jame Mosque

5. Kamranga Jame Mosque

6. Maulana Mosque

7. Mahuttuli Jame Mosque

8. Shahjadi Begum Jame Mosque

9. Malibag (Bangshal) Peyala Mosque

10. Samsabad Boro Mosque

11. Kosaituli Old Jame Mosque

12. Kosaituli Panchayet Committee and School

13. Bangshal RokonUddin Jame Mosque

14. Babubazar Ghat Jame Mosque

15. Anondomoyee Girls’ High School

16. Ahmed Bawani School and College

17. Haybotnagar Primary School

18. Samsabad Primary School

19. Jummon Community Center

20. Kona Party Center

21. Mokimbazar school

22. Ahmedabad School/ Hammadia School

23. Mahuttuli Primary School

24. Mosjid-e-Baitul-Mamur

25. Nobab Yousuf Market Mosque

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BNUS Annual Report-2010

ICUS Report 54

Table 3 shows a comparative view of these two methods. It is clear that most of thestructures fall below the cut-off score in the RVS method but in the Turkish Method, most ofthem fall above the cut-off score that means they don’t need any further detail analysis.
Table 3: Vulnerability assessment of Public Buildings using RVS and Turkish Method
Slno.

Building
Building name

HeightRVS
Score

Turkish Score
Level

Level

1

2

Building Building
Type

Occupancy

1Islampur Jame Mosque

7

0

60

52

C3

Religious

2

Shahjada Mia Jame Mosque

3

1.7

115

118

C3

Religious

3

Jabbu Khanam Jame Mosque

4

1.9

90

100

C3

Religious andCommercial

4

Jindabahar Jame Mosque

7

1.4

50

47

C3

Religious

5

Kamranga Jame Mosque

3

0.0

110

106

C3

Religious

6

Maulana Mosque

2

2.1

125

130

C3

Religious

7

Mahuttuli Jame Mosque

2

2.2

125

130

C3

Religious

8

Shahajadi Begum Jame

2

2.2

125

121

C3

Religious

6

2.4

65

42

C3

Religious

mosque9

Malibagh (Bangshal) Peyala
Mosque10

Samsabad Boro Mosque

2

2.2

120

125

C3

Religious

11

Kashaituli old jame mosque

2

2.6

-

-

URM

Religious

12

Kashaituli Panchayet

6

2.4

80

77

C3

Public use

Committee and School(Assembly)
andEducational

13

Bongshal Rokonuddin Jame

4

1.9

90

100

C3

Religious

1

2.6

-

-

URM

Religious

Structure-1

3

2.2

125

125

C3

Educational

Structure-2

3

2.2

125

123

C3

Mosque14

Babubajar Ghat Mosque

15

Anandomoyee Girls HighSchool61

March 2011

Structure-3

2

2.2

115

120

C3

Ahmaed Baowani College

4

1.9

-

-

URM

Ahmaed Baowani School

4

1.9

75

85

C3

17

Haibat Nogor Primary School

3

1.7

115

113

C3

Educational

18

Samsabad Primary School

5

1.9

75

72

C3

Educational

19

Jummon Community Center

3

1.7

125

125

C3

Public use

16

Educational(Assembly)
20

Kona Party Center

4

0.4

80

85

C3

Public use(Assembly)

21

Mokimbazar school5

2.4

Not surveyed

C3

Educational

22

Hammadia School3

2.2

Not surveyed

C3

Educational

23

Mahuttuli Primary School

3

2.2

-

-

URM

Educational

24

Mosjid-e-Baitul-Mamur

2

2.2

120

125

C3

Religious

25

Nobab Yousuf Market Mosque

30

Not surveyed

C3

Commercial
and Religious

Table 3 shows that the Islampur Jame Mosque, Jindabahar Jame Mosque, Kamranga Jame
Mosque, Malibagh (Bangshal) Peyala Mosque, Kona Party Center, Nobab Yousuf Market
Mosque requires more detail structural analysis based on the vulnerability assessment inboth methods. The proposed shelter buildings especially these six structures should beconsidered for certain preventive measures like retrofitting to be fit during earthquake andgive service as a post earthquake shelter.

Considerations in assessing the earthquake vulnerability of a building
According to Ansary and Noor, 2006 the general considerations in determining thevulnerability of a building are as follows:•

Shape of the building: The vulnerability of building depends on the shape of thebuilding. The shape of the buildings is generally L, T, Y, C, Circular, etc. The
irregular shape of the building is not susceptible to earthquake vulnerability. Square,
rectangular and circular shape building is effective for earthquake. C, L, T and Y
shaped buildings are not effective for earthquake protection.

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Length-Breadth Ratio: The length and breadth ratio of a building should not be
more than three (3).

•Extension of the building: The extension of a building should not be more than 1/6thof the breadth.

•Complex shape: The aperture (space) between the complex structures is mandatoryfor earthquake protection.

•

Height of the building: The height to breadth ratio of the building should not be
more than three.

•Reinforcement Distribution: Reinforcement distribution at column is very
important for earthquake. The intersection point between column and beam should bedesigned properly. The tie rods distribution from the intersection to 18” should be 4”
c/c and 8” c/c from the 18” to remain-end.

•

Column Spacing: The distance between two columns should not be more than 15 ft.

•

Number of columns: Number of columns should not be more than eight in one
direction.

•

Column size: Minimum nominal dimension should be 250 mm (10”)

Detail Evaluation of the Public Buildings
Based on the data found from Turkish Level I and Level II survey a more detail analysis of
the RCC types public buildings are done to make more effective evacuation proposals. The
detail Auto CAD drawing of the public buildings were assessed on vulnerability criterion.
Some of the RCC public buildings were assessed using Ferro scanner with the help of the
Department of Civil Engineering, BUET to justify the building condition with respect to its
coping capacity in future disaster. Dr. Mehedi Ahmed Ansary, Professor, Department ofCivil Engineering, BUET has performed the survey by himself with the assistance of BNUS
Staff. The findings from these surveys are discussed in the following sections.
a) Types of Building Structure
Mainly three types of structures- C3, C2 and URM were found in the study ward. But among
the public buildings 85% were C3 structures and only 15% was URM structure (see Figure 8)
i.e. only four buildings were unreinforced masonry building (URM) in the study area.
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Figure 8: Structure type of public building
Source: Field survey, 2009b) RVS Score for Public building
The Figure 9 shows that 54% public buildings RVS score is greater than cut off score 2 and
46% buildings have RVS score less than two. These buildings require further detail analysis
on vulnerability to determine the level of actual risk. If the cut off score 1.5 most of the
public buildings in the study area fall in safe side.

Figure 9:

Figure 10:

RVS score of the public building(cut off score 2)

RVS score of the public building(cut off score 1.5)c) Vertical Irregularity
It has found from field survey that 83% public buildings in the study area have regularity intheir elevation shape i.e. they are vertically regular and 17% buildings have irregular shape(see Figure 11)

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Figure 11: Vertical irregularity of public building
Source: Field survey, 2009d) Plan Irregularity
Irregularity in building plan is a deviation from a rectangular plan. Such deviation from plan
irregularity leads to irregularities in stiffness and strength distributions, which in turnincrease the risk of damage localization under strong ground excitations. In earthquake
resistant design, regularity in plan is encouraged. In the study area a number of publicbuildings have irregularity in plan. Figure 12 shows that about fourteen buildings haverectangular shape and nine buildings have irregular plan.

Figure 12: Plan irregularity of public building
Source: Field survey, 200965

March 2011e) Height of the Public Building
It has observed that among all public buildings in the study area 70% are one to three storied
and only 9% buildings are more than six storied (see Figure 13). It has also found that only
two public buildings (Islampur Jame Mosque and Zindabahar Jame Mosque) are sevenstoried.

Figure 13: Height according to storey of public building
Source: Field survey, 2009f) Soft Storey of the public building
Soft storey buildings are open ground storey buildings, consistently shown poor performance
during earthquakes. A significant number of them have collapsed. In the study area it has
found that 95% buildings have no open ground and only 5% public buildings have open
ground i.e. presence of walls at upper storey (See figure 14).

Figure 14: Soft storey of public building
Source: Field survey, 200966

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The existence of walls in upper storey makes them much stiffer than the open ground storey.
The existing open ground storey buildings need to be strengthened suitably to prevent themfrom collapsing during strong earthquake. The owners should seek the services of qualified
structural engineers who are able to suggest appropriate solutions to increase seismic safetyof these buildings.
g) Overhang of the public building
From field survey it has observed that most of the public buildings (84%) have no overhang
in their structures. These buildings expanded without any desecration of plan. Only threebuildings (16%) do not follow the plan and design accurately (see Figure 15).

Figure 15: Overhang of public building
Source: Field survey, 2009h) Pounding effect of public building
Seismic pounding between two adjacent buildings occur during an earthquake. It is one of
the main causes of severe building damages in earthquake. The non-structural damage
involves pounding or movement across separation joints between adjacent structures. In Old
Dhaka it is conspicuous that most of the buildings are constructed in congested way. So it isevident that 84% buildings in the study area might face pounding effect and only 16%
buildings are free from this (see Figure 16).

Figure 16: Pounding effect of public building
Source: Field survey, 200967

March 2011i) Short Column of public building
During past earthquakes, reinforced concrete (RC) buildings that have columns of different
heights within a storey, suffered more damage in the shorter columns as compared to tallercolumns in the same storey. The short column is stiffer as compared to the tall column and it
attracts larger earthquake force. If a short column is not adequately designed for such a large
force, it can suffer significant damage during an earthquake. Figure 17 shows short column
is identified in 16% buildings. In existing buildings with short columns, different retrofit
solutions can be applied to avoid damage in future earthquakes.

Figure 17: Short column of public building
Source: Field survey, 2009j) Detail Analysis of the public building
Building wise detail analysis is discussed in the following sections.
I. Islampur Jame Mosque
From the plan of structure it is found that the building shape is regular. The length andbreadth ratio of the building is more than three and column spacing is more than 15 ft that
increases the risk of the building to be vulnerable to earthquake hazard (see Figure 18).

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Figure 18: Building plan of Islampur Jame Mosque
Source: Field survey, 2009
From ferro scan of the building it has found that the beam and column dimensions areappropriate but the reinforcement distribution at beam and column are not sufficient.
Mezzanine floor was found in the ground floor of the building that made it more vulnerable
to earthquake. It can be concluded from the analysis that the building needs detail structural
analysis and earthquake resistant design can be applied as appropriate according to thebuilding condition like retrofitting to be used as a shelter (see Figure 19).

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March 2011

Figure 19: Findings from Ferro Scan of Islampur Jame Mosque
Source: Field survey, 2009

Photograph 6: Islampur Jame MosqueII.

ShahjadaMia Jame Mosque

The building is L-shaped that is not suitable in consideration with earthquake. The lengthand breadth ratio of the building is satisfactory (see figure 20).

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Figure 20: Building Plan of ShahjadaMia Jame Mosque
Source: Field survey, 2009
Beam and column dimension is appropriate. Reinforce distribution at column is not accurate(see Figure 21).

Figure 21: Findings from Ferro Scan of ShahjadaMia Jame Mosque
Source: Field survey, 200971

March 2011

Photograph 7: ShahjadaMia Jame MosqueIII. Jhubbu Khanam Jame Mosque
From plan of the structure it is found that the structure is nearly regular in shape that is allright considering reaction in earthquake. The length and breadth ratio of the building is also
adequate (see Figure 21).

Figure 22: Building Plan of Jhubbu Khanam Jame Mosque
Source: Field survey, 200972

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From Ferro Scan and visual observation it has found that the building’s roof is flat plate. It is
not suitable considering earthquake resistant building design. The reinforcement distribution
in beam and column is not sufficient. The spacing within column is not appropriate (seeFigure 23). Thus the building needs preventive measures like retrofitting to sustain during
time of earthquake.
10"

5"
4"

9"

4" 4" 4"
4"

1'-8"

10"

6" 6"

3" 3" 3"

11"

7"

10"

16"

8"

11"

3.5"

8"

10"

8"

16"

Figure 23: Findings from Ferro Scan of Jhubbu Khanam Jame Mosque
Source: Field survey, 2009

Photograph 8: Jhubbu Khanam Jame Mosque73March 2011

IV. Zindabahar Jame Mosque
From the plan of Structure it is found that the structure is regular in shape that is acceptableconsidering earthquake. But the building has little overhang that is not correct for earthquake
resistance design (see Figure 24).

Figure 24: Building Plan of Zindabahar Jame Mosque
Source: Field survey, 200974

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From Ferro Scan and visual observation it was found that the building’s roof is flat plate thatis not suitable for proper functioning at time of earthquake (see Figure 5.25). So the building
needs preventive measures like retrofitting to sustain during time of earthquake.

3"

10"

10"

9"

3"

10"

10"

9"

11"

8"

Figure 25: Findings from Ferro Scan of Zindabahar Jame Mosque
Source: Field survey, 2009

Photograph 9: Zindabahar Jame Mosque
V. Kamranga Jame Mosque
It is clear from the plan of the structure that it is almost regular in shape that is acceptable inearthquake consideration (see Figure 26).

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Figure 26: Building Plan of Kamranga Jame Mosque
Source: Field survey, 2009

Photograph 10: Kamranga Jame Mosque
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VI. Maulana Mosque
The building plan is almost regular in shape that is all right considering earthquake resistantdesign (see Figure 27).

Figure 27: Building Plan of Maulana Mosque
Source: Field survey, 2009
VII. Mahuttuli Jame Mosque
From figure it is seen that the building plan is regular. The length breadth ratio is ok (seeFigure 28).

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Figure 28: Building Plan of Mahuttuli Jame Mosque
Source: Field survey, 2009

Photograph 11: Mahuttuli Jame Mosque

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VIII. Shahjadi Begum Jame Mosque
The building plan is not perfect as the shape is irregular and the length breadth ratio of thebuilding is more than three and it is not accurate according to earthquake resistant building
design (see Figure 29).

Figure 29: Building Plan of Shahjadi Begum Jame Mosque
Source: Field survey, 200979

March 2011

Photograph 12: Shahjadi Begum Jame Mosque
IX. Malibag (Bangshal) Peyala Mosque
The building plan according to its shape and length-breadth ratio is accurate. The building isless vulnerable to earthquake hazard (see Figure 30).
.

20'

20'

10'

10'

10'

10'

10'

10'

20'

20"

10"

Figure 30: Building Plan of Malibag (Bangshal) Peyala Mosque
Source: Field survey, 200980

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Photograph 13: Malibag (Bangshal) Peyala Mosque
X. Samsabad Boro Mosque
The building plan is square in shape. The building is comparatively less vulnerable toearthquake (see Figure 31).

12"

12"

Figure 31: Building Plan of Samsabad Boro Mosque
Source: Field survey, 200981

March 2011

Photograph 14: Samsabad Boro Mosque

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XI. Kosaituli Old Jame Mosque
From field survey and analyzing design, the building was found highly vulnerable toearthquake. The building plan is irregular in shape. There was existence of mezzanine floor.
Also RCC structures were built with the old aged URM building for extension of thestructure making it more vulnerable to earthquake (see Figure 32). The building also
represents a significant historical site in the area. Therefore the structure needs more analysis
by structural engineers to be proposed as earthquake evacuation shelter.

11"

10"

18"

12"

Figure 32: Building Plan of Kosaituli Old Jame Mosque
Source: Field survey, 200983

March 2011

Photograph 15: Kashaituli Old Jame Mosque
XII. Kosaituli Panchayet Committee and School
The building shape is regular but the length breadth ratio is not adequate (see Figure 5.33).
Building extension was not made accurately.

Figure 33: Building Plan of Kosaituli Panchayet Committee and School
Source: Field survey, 200984

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From Ferro scan it was found that the reinforcement distribution in the column was notcorrect (see Figure 34). Over all the building needs special consideration to be used as
evacuation shelter during emergency time.

Figure 34: Findings from Ferro Scan of Kosaituli Panchayet Committee and School
Source: Field survey, 2009

Photograph 16: Kosaituli Panchayet Committee and School85March 2011

XIII. Bangshal RokonUddin Jame MosqueThis building is almost regular in shape. The length and breadth ratio is acceptaple but thecolumn spacing is not correct (see Figure 35).

Figure 35: Building Plan of Bangshal RokonUddin Jame Mosque
Source: Field survey, 2009

Photograph 17: Bangshal RokonUddin Jame Mosque
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XIV. Babubazar Ghat Jame MosqueThis is an old URM building situated on the bank of river Buriganga and standing as a landmark of historical site. The building shape is regular along with column spacing (see Figure36). The existing heavy load bearing walls in the building will carry the extra load fromground shaking during earthquake. The building has a handsome amount of open space
circling the main building. It can serve as a proper shelter place for the local residents.

42'-5"

10'-10"

9'-4"

9'-4"

9'-4"

9'-4"

2'

9'-4"

9'-4"

10'-5"

24'-6"

7'-4"6'-10"

25'
1'

10"

24"

10"

Figure 36: Building Plan of Babubazar Ghat Jame Mosque
Source: Field survey, 2009

Photograph 18: Babubazar Ghat Jame Mosque87March 2011

XV. Anondomoyee Girls’ High School
From the plan of 1st structure it can be said that the building shape is irregular, its extension is
not 1/6 th of width, the length and breadth ratio of the building is not perfect as it is more than
three and column spacing is more than 15 ft that increases the risk of the building to bevulnerable to earthquake hazard (see Figure 37). In terms of structure 2 and 3 the shape isregular, their length and breadth ratio is considerable but their column spacing has not
maintained the standard of being within 15 ft.

Figure 37: Building Plans of Anondomoyee Girls’ High School
Source: Field survey, 200988

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From the column section in the figures of three structures it can be said that the reinforcement
distribution also not followed the standard to be judged as earthquake resistant building. But
the RVS Score and Score from Turkish Level II survey has declared the building structures
could be safe as it showed values above the cutoff score (see Figure 38).

10"
6"

16"
20"

4"

9"
9"
8"

10"
8"

6"

9"

9"

9"
11"
10"

4"

4"

7"

8"

5"

8"

9"

11"

10"

11"

8"

12"

6"

11"

20"

5"

6"

9"

6"

3"
3"

16"

7"
11"

9"

6"

5"

7"

6"
10"
11"

16"

16"

7"
11"

Figure 38: Ferro scan result of Anondomoyee Girls’ High School
Source: Field survey, 200989

March 2011

Photograph 19: Anondomoyee Girls’ High School
After analyzing the above situations the building structures can be suggested for further
investigation by the structural engineers and retrofitting or other measures of strengthening
the existing structures to withstand earthquake calamity are suggested here.

Photograph 20: Prof. Ansary and BNUS Staff performing Fero-Scan of the School Building

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XVI. Ahmed Bawani School and College
The building plan is not regular in shape. The length and breadth ratio of the building is also
not accurate according to earthquake resistant building design (see Figure 39). The left
portion of the drawing is the college section with RCC building structure and the right
portion is school section with an URM type structure. Two structures are positioned in such a
way that it looks like a same building and as the two structures are connected with each otherwith different floor heights it behave like a mezzanine floor which is very bad feature for abuilding to behave well during earthquake. It needs certain preventive measures to act as anevacuation shelter.

Figure 39: Building Plan of Ahmed Bawani School and College
Source: Field survey, 2009

Photograph 21: Ahmed Bawani School and College

91March 2011

XVII. Haybotnagar Primary School
The shape of the building is irregular. The extension is not 1/6 th of its width but the column
spacing is ok (see Figure 40). Above all the building needs further analysis and measures tobe sustain in times of earthquake and work perfectly as a shelter.

Figure 40: Building Plan of Haybotnagar Primary School
Source: Field survey, 2009

Photograph 22: Haybotnagar Primary School
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XVIII. Samsabad Primary School
The shape of the building along with its length breadth ratio is ok (see Figure 41). But thecolumn spacing is not accurate. It needs more study and specific treatments to be used as ashelter place.

20'

10'

5'

18"

Figure 41: Building Plan of Samsabad Primary School

12"

2'

12'

12'

20'

Source: Field survey, 2009

Photograph 23: Samsabad Primary School

93March 2011

XIX. Jummon Community Center
The building shape is irregular. Extension is more than one sixth of its width (see Figure 42).

Figure 42: Building Plan of Jummon Community Center
Source: Field survey, 2009
Reinforcement distribution at column is incorrect. The building needs more detail evaluation
and based on those results building specific preventive measures like retrofitting and others
should be taken to be performed as an earthquake evacuation shelter (see Figure 43).

Figure 43: Ferro scan result of Jummon Community Center
Source: Field survey, 200994

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Photograph 24: Jummon Community Center
XX. Kona Party Center
The building shape is regular. The length breadth ratio with its column spacing is correct (seeFigure 44)

Figure 44: Building Plan of Kona Party Center (Ground Floor)
Source: Field survey, 200

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March 2011

Photograph 25: Kona Party Center

SummaryThis chapter analyzes the vulnerability of 77% surveyed building in the study area using
FEMA-RVS method. Only the proposed evacuation shelters were assessed in detail using
Turkish Level-I and Level-II methods. It was found from field survey using RVS method that
54% of the building falls below the FEMA declared cut-off score i.e. ‘2’. Considering cut-off
score of ‘1.5’, only 39% of surveyed buildings were found for further detail analysis by
structural engineers. In the study area huge amount of buildings with plan irregularity andvertical irregularity were found that made the scenario worst considering earthquake
vulnerability. The existence of old dilapidated building is also a reason for the area to beearthquake vulnerable. Finally the findings for proposed evacuation shelters were analyzed indetail to have a clear idea on the shelter buildings and to have specific recommendations inretrofitting the structure based on existing condition.

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PART-V

INSTALLATION OF A DIGITAL EARTHQUAKEMONITORING SYSTEM FOR BANGLADESHBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Md. Shamsur Rahman
Mehedi Ahmed Ansary

ICUS Report 54
1.

Introduction

Five large earthquakes occurred in Bangladesh and neighboring region between 1869 and
1930. Recently, no large earthquakes occurred in Bangladesh. A large earthquake may occur
any time in the future. For seismic hazard analysis earthquake monitoring is important.
Recently twenty five accelerometers (Model-ETNA) were deployed in Bangladesh. Anotherseven accelerometers were deployed within a 60 Km radius of Jamuna bridge in 2003 andthirty four Strong Motion Accelerograph (SMAs) were also deployed in PWD offices all overBangladesh in 2005. Under the guidance of Professor Dr. Mehedi Ahmed Ansary,
Department of Civil Engineering, Bangladesh University of Engineering and Technology(BUET), the accelerometers are being maintained. To assist in the various works during the
installation and monitoring phases Md. Samsur Rahman, was appointed as a Research
Assistant from January 01, 2010.
An earthquake is a sudden and violent motion of the earth usually caused by volcanic
eruption, plate tectonics, or man-made explosions which lasts for a short time, and within avery limited region. Most earthquakes last for less than a minute. The larger earthquakes arefollowed by a series of after-shocks which also may be dangerous. Volcanic eruption or plate
tectonics is responsible for causing earthquakes. Also small earthquakes can be caused byblasting, quarrying and mining. Man made earthquakes are like underground nuclear
explosions. But plate tectonics cause large number of big earthquakes. Bangladesh did nothave any modern recording station for monitoring strong ground motion. The relationshipbetween magnitude, epicentral distance and peak ground acceleration of those earthquakes
constitute the basic parameter needed for assessing seismic hazard at a given site. The
purpose of acclerometer installation is to present a predicting model for accelerationattenuation for earthquakes in Bangladesh and its neighboring region.
2.

Objectives

During the last two centuries, Bangladesh and its neighboring region have experienced
several large earthquakes. The peak ground acceleration of these earthquakes has been
estimated using different existing attenuation laws. For earthquake hazard analysis, unified
acceleration attenuation relationship for Bangladesh is required.

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March 2011

The major objective of the study is to compile digital earthquake records for Bangladesh.
3.

Seismic Measurement Device Installation Works

3.1 Base casting /Foundation for model ETNA Instrument
At first, the location of the ETNA instruments is selected. The Strong Motion Instrument
must be situated on the ground surface. The soil condition must be dense sand/stiff clay. The
trench size is 1050mm x 1050mm x 450mm. In the sand filling and brick flat soling (B.F.S) is
450mm and finally Concrete Base-1 Foundation Casting size is 900mm x 900mm x 150mm
and RCC casting ratio is 1: 2: 4 and in another base casting size is 400mm x 400mm x
100mm. Figure 1 shows the concrete base for the ETNA. BUET team started working fromFebruary 02, 2010 for installing the seismic instruments. Work plan and schedule wasformulated to finish the installation work within two month. The Seismic Measuring Device
Installation photographs are shown in Appendix-B. Public Works Department (PWD), Local
Government, Bangladesh Atomic Energy Commission (BAEC), Geological Survey ofBangladesh (GSB), Jamuna Multipurpose Bridge Authority (JMBA) provided necessary
space, support and assistance. Figure 2 and Table 1 present the locations of digital
accelerometers.
3.2

Protections of ETNA-Station and Electrical Connections

Iron grill and galvanized steel sheet fencing is put around the ETNA-Instrument forprotection. Each of the free field stations is setup individually. The systems are powered bybatteries that are charged by AC power supply. At this moment the data is collected manuallyby downloading the data into a laptop computer. All the sensors are placed in their designatedpositions and each of them is connected to one particular channel of a recorder.

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400

250

250

250

A

250

900

400

A

First stageof casting

900 mm
PLAN
250

400

45

250

150

3-10mmdia(bothway)

Second stageof casting100

6mm dia nut

900
SEC: A-A

7-12mm dia bar(bothway)

NOTE: Alldimensions are in mm.
Concrete to be used 1:2:4

Figure 1. Concrete Base Foundations for ETNA-Instrument

Figure 1. Free field ETNA Instrument Setup

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March 2011

Table 1. Digital Free-field Instruments (ETNA)

100

SL.No

Model

Location

LatitudeLongitude

1

ETNA

PWD, Ashkona-Hazi camp

23.710N

90.380E

2

ETNA

Pollice Staff College

23.720N

90.250E

3ETNA

GSB-Dhaka

23.750N

90.350E

4ETNA

GSB-Chittagong

22.150N

91.800E

5ETNA

PWD, Cox’s-bazar

21.420N

91.890E

6ETNA

PWD, Bandarban

22.250N

92.320E

7ETNA

PWD, Rangamati

22.720N

92.380E

8ETNA

PWD, Khagrachari22.450N

92.180E

9ETNA

PWD, Sunamganj

25.070N

91.320E

10ETNA

PWD, Sylhet

25.150N

91.250E

11ETNA

PWD, B.Baria

23.920N

91.250E

12ETNA

PWD, Moulvibazar

24.350N

91.720E

13

ETNA

Koroytoli Deepo, Haluaghat

22.450N

92.180E

14ETNA

PWD, Sherpur

25.150N

90.120E

15ETNA

PWD, Netokona

24.720N

90.650E

15ETNA

PWD, Kishoreganj

24.350N

90.920E

16ETNA

PWD, Satkhira25.350N

88.120E

17ETNA

PWD, Meherpur

23.750N

88.620E

18

ETNA

Atomic E. C. Rooppur-Pabna

23.420N

88.750E

19ETNA

PWD, Rangpur

25.800N

89.200E

20ETNA

PWD, Lalmonirhat

25.900N

89.350E

21ETNA

PWD, Kurigram

25.600N

89.800E

22ETNA

PWD, Panchagarh

26.150N

88.250E

23ETNA

PWD, Meherpur

23.250N

88.620E

24

ETNA

LGED-Gazipur

23.750N

90.850E

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Figure 2. Location of ETNAs

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3.3

System Testing

After the sensors are connected, they have to go through the Functionality Test done with theoperating software. Then they have to be corrected for any offsets in the readings. Once all ofthese are done for each of the sensors, the system is ready. It has been tested to see if datafrom all the channels are reaching the recorders and whether they are set at real time throughGPS. The GPS are set at UTC time as stated in the original documents. The system is suchthat each of the sensors can be configured separately, but they are kept the same at the
beginning. Each sensor can be set to trigger the whole system. The trigger value for thetwenty four free-field ground accelerometers was set at 0.25% of 2g (5 cm/sec2). Whenever
the acceleration exceeds the trigger value, automatic data recording will take place.
3.4

Software Installation

There are some custom-made softwares that came with the instruments to operate and monitor
the whole system. One can also interact with the instruments (i.e., K2s) using the software

called Quick Talk and changes the settings. Quick Talk and Quick Look may also be used for
downloading or viewing the incoming data without any processing.

To process, analyze and interpret the data, the software called Strong Motion Analyzer(SMA) is used. One can perform necessary filtering, corrections and plotting of the signals
received from the sensor.
All the softwares are installed at the server at the Data Control Center and they are usedduring the initial checks of the system. For analysis and processing of data, the software
SMA has been later installed in the data analysis computer.

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4.

Recorded Accelerometer Data

After installation has been completed in May 2010, acceleration data of two earthquakes havebeen recorded by the installed accelerometers. All the data recorded during these twoearthquakes are presented in Appendix-A.
4.1

September 10, 2010: Chandpur Earthquake

On September 10, 2010 Chandpur Earthquake has been recorded by the free-field stations
Brahmanbaria, Hazicamp and GSB-Segunbagicha at 22:25:50 hrs BST (16:25:50 hrs GMT,
September 10, 2010). Magnitude of this earthquake has been 4.6 and depth 25 Km.
Maximum acceleration of this earthquake is at Hazicamp. The PGA value is 10.83 cm/sec2 in
East-West direction.
4.2

September 11, 2010: Assam Earthquake (Meghaloy)

On September 11, 2008 Assam Earthquake has been recorded by the free-field stations
Kurigram, Panchagarh, Bogra, Natore and Sherpur at 10:42:55 hrs BST (04:42:55 hrs GMT,
September 10, 2010). Magnitude of this earthquake has been 4.7 and depth 33 Km.
Maximum acceleration of this earthquake is at Kurigram. The PGA value is 18.08 cm/sec2 inNorth-South direction.
5.

Conclusions and Recommendations

The Seismic Instrumentation Project has entered a very significant stage with the setup andoperation of the digital seismic instruments. It is hoped that with the necessary adjustments
done in time, the system will yield valuable data to the local researchers to have better ideason the performance of the bridges and free-field stations as well as seismic activities of thewhole region. For the next few years we need to record such earthquake data to develop theattenuation law for Bangladesh. This attenuation law will help us to develop the seismic
zonation map for Bangladesh.
Acknowledgement
The fund obtained for undertaking the work from CASR, BUET is gratefully acknowledged.
103March 2011

APPENDIX-A
TIME HISTORY RECORDED BY THE FREE-FIELDSTATIONS DURING CHANDPUR
AND MEGHALOY EARTHQUAKES

104

BNUS Annual Report-2010

-6

-3

0

-8

-6

-4

-2

0

2

4

6

8

0

0

-3

-2

-1

0

1

2

3

0

T im e ( s e c )U D - d ir e c tio n

2

-8

-6

-4

-2

0

2

4

6

0

N S - d ir e c tio n

T im e ( s e c )T im e(s e c )

2 0

-8

-4

0

4

8

0

(s e c )2 0

T im eN S - d ir e c tio n

-8

-4

0

4

8

0

U D - d ir e c tio n

20

T im e ( s e c )Figure A2. Time history of GSB-Dhaka free-field station during the Chandpur Earthquake of September 10, 2010

E W - d ir e c t io n

Figure A1. Time history of Brahmanbaria free-field station during the Chandpur Earthquake of September 10, 2010

T im e ( s e c )223

Acceleration (cm/sec )Acceleration (cm/sec )2

2

Acceleration (cm/sec )2

Acceleration (cm/sec )acceleration (cm/sec )E W - d ir e c tio n

Acceleration (cm/sec )6

25

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105

2

-6

-3

0

3

6

0

-1 6

-8

0

0

-1 6

-8

0

8

0

N S - d ir e c t io n

T im e ( s e c )Acceleration (cm/sec )2

Acceleration (cm/sec )

2

-1 6

-8

0

8

16

0

U D -d ire c tio n

T im e (s e c )T im e (s e c )

-6

-4

-2

0

2

4

6

0

N S - d ir e c t io n

T im e ( s e c )

-4

-2

0

2

4

0

U D - d ir e c tio n

T im e ( s e c )Figure A4. Time history of Sherpur free-field station during the Meghaloy Earthquake of September 11, 2010

E W -d ir e c tio n

Figure A3. Time history of Hazicamp free-field station during the Chandpur Earthquake of September 10, 2010

T im e ( s e c )2

8

E W - d ir e c t io n

Acceleration (cm/sec )Acceleration (cm/sec )2

Acceleration (cm/sec )

16

2

106
Acceleration (cm/sec )16

March 2011

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-3

-2

-1

0

1

2

3

-8

-4

0

0

0

-8

-4

0

4

0

N S - d ir e c tio n

T im e ( s e c )8Acceleration (cm/sec )

2

-8

-4

0

4

8

0

T im e (s e c )

-6

-4

-2

0

2

4

6

0

N S -d ire c tio n

T im e (s e c )

-3.0

-1.5

0.0

1.5

3.0

0

UD-direction

Time (sec)Figure A6. Time history of Natore free-field station during the Meghaloy Earthquake of September 11, 2010

E W -d ire c tio n

8

T im e ( s e c )U D - d ir e c t io n

S e p t e m b e r 1 1 , 2 0 1 0 M e g h a lo y E Q : M s = 4 . 6

Figure A5. Time history of Panchagarh free-field station during the Meghaloy Earthquake of September 11, 2010

T im e (s e c )

8

2

2

4

Acceleration (cm/sec )Acceleration (cm/sec )2

2

E W -d ire c tio n

2

Acceleration (cm/sec )Acceleration (cm/sec )8

Acceleration (cm/sec )8

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107

Acceleration (cm/sec )

2

-1 5

-1 0

-5

0

5

10

15

0

-6

-3

E W - d ir e c t io n

0

40

-6

-3

0

3

6
N S -d ire c tio n

Acceleration (cm/sec )

2

-6

-3

0

3

6

0

U D - d ir e c tio n

40

T im e ( s e c )-1 50

N S - d ir e c t io n

T im e ( s e c )

-1 5

-1 0

-5

0

5

10

15

0

U D - d ir e c t io n

T im e ( s e c )Figure A8. Time history of Kurigram free-field station during the Meghaloy Earthquake of September 11, 2010

T im e ( s e c )

-1 0

-5

0

5

10

15

Figure A7. Time history of Bogra free-field station during the Meghaloy Earthquake of September 11, 2010

T im e ( s e c )20Acceleration (cm/sec )Accleration (cm/sec )3

E W - d ir e c t io n

2

2

108
Acceleration (cm/sec )6

March 2011

BNUS Annual Report-2010

Accleration (cm/sec )2

PART-VI

CHARACTERISTICS OF MICROTREMOR FOR
A 110 MW POWER PLANT IN SOUTH
WESTERN REGION OF BANGLADESHBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Ram Krishna MazumderMehedi Ahmed Ansary

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ICUS Report 54

1. INTRODUCTION
In areas of low or moderate seismic activity, the effects of possible large earthquakes areusually explored through earthquake scenarios. One of the main parameters controlling thepossible consequences of strong events is the ability of the structure to resist to the groundmotion. Aim of this study is to obtain the characteristics of microtremor for the power plant
at different conditions.
Microtremor is used to record the fundamental frequency and period of the structure and soil.
The dynamic properties are the important factor for seismic design. Response of structure
mainly depends on the characteristics of both excitation forces and dynamic properties ofstructures. This is why the natural frequency and period is taken on the basement, cement
concrete floor to identify the dynamic properties of structures. The vibration characteristics insoil are different to structure. Hard soil gives high frequency and soft soil gives low
frequency [4]. A structure may experience a vibration period at which it oscillates in theearthquake vibration motion and will tend to response to that. Natural frequency of structure
is obtained based on the spectral characteristics of horizontal component of the structure tothat of ground.
First Fourier Transform (FFT) of foundation, concrete floor and free-field are similar during
the full vibration of the machine load and zero vibration consideration for the power plant.
2. STUDY AREA
The studied power plant has the capacity of 110 MW is situated near the bank of Padma
River, south western part of Bangladesh. The plant was established in 2010. There have total
14 machines to generate the power. The study was considered during the full vibration (fourmachines running at a time) to compare the results with the machines at rest. Fig 1 shows thestudy area.

BNUS Annual Report-2010109

March 2011

Fig 1: Study area of the microtremor.
3. MICROTREMOR OBSERVATION
Soil characteristics can be assessed by Microtremor measurement. Hard soil gives highfrequency and soft soil gives low frequency. A structure may experience a vibration period atwhich it oscillates in the earthquake vibration motion and will tend to response to that.
Natural frequency of structure is obtained based on the spectral ration of horizontal
component of the structure to that of ground. Wave propagation mechanism of Microtremor
and its relation with ground vibration characteristics were studied from the beginning ofMicrotremor studies [4], [6].
Basically there are two types of Microtremor observations to the number of observation
points. These are point and array observations of microtremors [5]. From the arrayobservation of Microtremor of period greater than 1 sec, Rayleigh-wave and Love-wave
originating from natural sources, such as sea wave, variation of air and wind pressure can berecognized. On the other hand, short-period Microtremor of period less than 1 sec is thought
to be generated by artificial noises such as traffic vehicles, industrial plants, household
appliances, etc. Some researches [3], [2] have showed that microtremors are mainlycomposed of Rayleigh-wave and some researchers [7] have showed that short-period
Microtremor bears resemblance to shear-wave characteristics. On the other hand,
Microtremor can also be dominated by Love–wave [1]. Recently, Suzuki et al. (1995) haveapplied Microtremor measurements to the estimation of earthquake ground motions based on
110

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a hypothesis that the amplitude ratio defined by Nakamura can be regarded identical with halfof the amplification factor from bedrock to the ground surface. However, the real generationand nature of microtremors have not yet been established.
In general, the approaches to the identification the dynamic properties of structure can be
categorized into three main approaches: (1) empirical, (2) numerical analysis, and (3) direct
measurement approaches. The empirical approach provides simplified formulas for
estimating the fundamental periods of structures in terms of geometric dimensions of thestructures. The second approach, the numerical analysis, is normally used during the design
process. A finite model of the structure is first formulated. Dynamic properties such as
natural frequencies and vibration mode shapes are obtained by the Eigen analysis. The third
approach is the direct measurement approach, which first measures dynamic responses ofexisting structures, and then identifies their dynamic properties from the measured responses.
4. SOIL DATA
For this site, Standard Penetration Test was performed for 18 bore holes. These are obtained
from subsoil investigation. Typical boreholes are shown in Fig 2. This 110 MW power plant
is constructed on pile foundation.

Fig 2: Measured subsoil SPT values for three bore holes.
In general, the top several feet of soil consists of yellowish brown silt with fine sand, the nextlayer contains medium plastic clay and the bottom layer consists of thick medium dense todense yellowish brown fine sand.
5. DATA COLLECTION AND PROCESSING
For Microtremor observation at the power plant, initially the sensors are deployed. One
sensor is fixed on the machine basement, one on the free field near the structure and anotheron concrete floor as shown in Fig 3. At first data was recorded during the machines running
BNUS Annual Report-2010111

March 2011at full load, then data was recorded when all machines were in rest. After taking theobservation with the help of microtremor program the time domain velocity data is converted
to frequency domain data and find out the natural period of the structures were found.
Microtremor measurement is shown below in Fig 4. Around the investigated structure three
3-dimensional accelerometers are assembled to measure the ground response of the ambient
excitation.

Fig 3: Instrument for ambient vibration measurement

3-D

Microtremor
Fig 4: Microtremor data observation
The computation steps of the spectrum analysis is shown in Fig 5 and described as follows:•

112

Pre-Processing:

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ICUS Report 54- 3-dimensional input (the accelerometer in northward direction to get North-South, EastWest and vertical components)- Windowing of the signal (in our case only the ambient parts are of interest, observe, incase of transient excitation only the transient parts of the time response are of interest)•

Main Data-Processing:Hence the three different components of the signal were considered separately. The main
data processing is repeated for every input-signal (n-Steps according to the numbers of
preliminary separated windows).
- FFT is applied to obtain the several spectral amplitudes of the three components- Smoothing of the three spectral amplitudes with a bandwidth factor of 15- Afterwards the resulting horizontal component and vertical component are plotted toobtain the amplitude in frequency domain
Pre-Processing
3-D force-balanceaccelerometer

Ambient Excitation

3-D time history response(sampling rate 100 Hz)

Data-Processing
FFT (NS)

North-South-Comp. (NS)FFT (EW)

East-West-Comp. (EW)FFT (V)

Vertical-Component (V)Smoothing (V)Smoothing (EW)

Spectrum Analysis

Smoothing (NS)Fig 5: Flowchart of data processing

BNUS Annual Report-2010113

March 2011

6. RESULTS
Fig 6 shows individual time histories for North-South, East-West and Up-Down components
for free-field, concrete floor and machine foundation. Fig 7 shows FFT of those time histories.
In this site, separation between machine foundation and surrounding soil is essential but noseparation has been kept. This can be seen from Fig 7. As for fully loaded condition,
predominant frequency is 8 Hz at all locations; Machine base has high amplitude, but on
concrete floor and ground level amplitude decreased. With zero load, frequency is 3 Hz; but
amplitude was 100 times lower than fully loaded condition. All amplitude is presented in
micrometer.
Machine running with full load

Machine at rest
NS

10

Amplitude

Amplitude

NS

20

2000

1000

0

0

-10

-1000

-20

-2000
0

5

10

15

0

20

5

10

15

20

Period (s)Period (s)
25

EW

20

EW

15
10

Amplitude

Amplitude

400

200

5
0
-5

0

-10
-15

-200

-20
-25

-400
0

5

10

15

5

10

15

20

25

UD

20
15

UD

Amplitude

3000

20

Period (s)Period (s)2000

Amplitude

0

1000

10
5
0
-5

0

-10
-15

-1000

-20

-2000

-25
0

-3000
0

5

10

15

5

20

10

15

20

Period (s)Period (s)3-D accelerometer on machine basement

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ICUS Report 54
25

NS

NS

20

400

15

Amplitude

Amplitude

200

0

10
5
0
-5
-10

-200

-15
-20

-400

-25
0

5

10

15

20

0

5

400

10

15

EW

20

EW

300

Amplitude

200

Amplitude

20

Period (s)Period (s)

100
0

10

0

-10

-100
-200

-20
-300
0

5

10

15

0

20

5

1500

10

15

20

Period (s)Period (s)
UD

UD

20

10

500

Amplitude

Amplitude

1000

0
-500

-10

-1000
-1500

0

-20
0

5

10

15

0

20

5

10

15

20

Period (s)Period (s)3-D accelerometer on concrete floor
25

500
400

15

200

Amplitude

Amplitude

300

100
0
-100

10
5
0
-5
-10

-200

-15

-300

-20

-400
-500

NS

20

NS

-25
0

5

10

15

20

0

5

20

600

15

400

10

200
0
-200

EW

0
-5
-10

-600

-15

-1000

20

5

-400

-800

15

25

EW

800

Amplitude

Amplitude

1000

10

Period (s)Period (s)

-20
0

5

10

Period (s)

15

20

-25

0

5

10

15

20

Period (s)BNUS Annual Report-2010115

March 2011
1500

UD

UD

20

500

Amplitude

Amplitude

1000

0
-500

10

0

-10

-1000

-20
-1500
0

5

10

Period (s)

15

20

0

5

10

15

20

Period (s)3-D accelerometer on free-fieldFig 6: Time history data at different conditions and at different locations.

116

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ICUS Report 54

Machine running with full load

Machine at rest
1.6

NS
EW
UD

100

NS
EW
UD

1.4

Amplitude

Amplitude

1.2

10

1.0
0.8
0.6

1

0.4
0.2

0.1

0.0

0.1

1

0.1

10

1

10

Frequency (Hz)Frequency (Hz)3-D accelerometer on machine basement
1.6

NS
EW
UD

100

NS
EW
UD

1.4

Amplitude

Amplitude

1.2

10

1.0
0.8
0.6

1

0.4
0.2

0.1

0.0
0.1

1

10

0.1

1

10

Frequency (Hz)Frequency (Hz)3-D accelerometer on concrete floor
1.6

NS
EW
V

100

NS
EW
UD

1.4

Amplitude

Amplitude

1.2

10

1.0
0.8
0.6

1

0.4
0.2

0.1

0.1

1

10

0.0

0.1

Frequency (Hz)1

10Frequency (Hz)3-D accelerometer on soil
Fig 7: Smoothed data of horizontal and vertical Fourier spectra of microtremors.
BNUS Annual Report-2010117

March 2011

7. CONCLUSION
This paper summarizes the microtremor observations at different locations of the power
station. Microtremor observations have been made on machine foundation, concrete floor andfree-field for 10 minute. The reading has been repeated for two times to check the stability of
the acquired data. From observation, no separation has been found between machinefoundation and surrounding soil. For fully loaded condition, predominant frequency is 8 Hz
at all locations; Machine base has high amplitude, but on concrete floor and ground level
amplitude decreased. For machine at rest, amplitude was 100 times lower than fully loaded
condition with frequency 3 Hz.
REFERENCES[1] Tamura, T., O. Nagai, H. Kikubo, and H. Sumita (1993). Charactesistics of wave group
microtremors obtained by array measurement, J. Struct. Consr. Eng. AIJ 449, 83-91 (inJapanese).
[2] Tokimatsu, K. and Y. Miyadera (1992), “Characteristics of Rayleigh waves in
microtremors and their relation to underground structures, J.stucture. consr. Eng. AIJ 439, 8187
[3] Sato, T. H. Kawase, M. Matsui, and S. Kataoka (1991). Array measurement of highfrequency microtremors for underground structure estimation, proc. 4th int. conf. on seismic
zonation, 11,409-416[4] Aki, K. (1957). Space and time spectra of stationary stochastic waves, with specialreference to microtremors, Bull. Of earthquake research institute, 35, 415-456.
[5] Ansary, M.A., Yamazaki, F. and Katayama, T. (1996). Application of Microtremor
Measurements to the estimation of site amplification characteristics, Bulletin of ERS, Vol 29,
PP: 96-113.
[6] Kanai, K. and Tanaka T. (1961). On Microtremor VIII, Bull.Earthq. Res.Inst. Tokyo
University, Vol.39, pp.97-114.
[7] Nakamura, Y. (1989). A method for dynamic characteristics estimation of subsurface
using microtremor on the ground surface, QR of RTRI, 30, 25-33

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PART-VII
SEISMIC VULNERABILITY ASSESSMENT OFEDUCATIONAL BUILDINGS IN OLD DHAKABANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Ram Krishna MazumderMehedi Ahmed Ansary

BNUS Annual Report-2010

ICUS Report 54

Introduction
This report is prepared by Bangladesh Network Office for Urban Safety (BNUS) as part of
the qualitative earthquake vulnerability assessment of educational buildings in Wari, locatedat ward no. 74. The report describes the method and findings of the assessment, which wasdone in October 2010. Recommendations are provided for improving seismic performance of
the assessed buildings.
This report is based on the methodology described in Section 2 and best engineering
judgment arrived at from the site visit, review of available architectural drawings, and nondestructive test carried out at site. All possible efforts have been made to provide accurate
and authoritative seismic vulnerability assessment of the building in the given circumstancesof information provided by the client and limited number of field-tests. Therefore, neither
BNUS nor any of its employees make any warranty, expressed or implied, nor assumes any
responsibility for the accuracy, completeness, or usefulness of the statement made in thisreport in case the starting information does not stand correct.
The seismic evaluation process generally consists of two phases. The first phase is qualitative
method to identify the seismic deficiency of the building. The evaluation involves a set ofchecklist and identifies areas of potential weakness in the building. If seismic deficiency ofthe building is not up to the acceptable level either second phases or demolition isrecommended. The second phase involves the details seismic evaluation followed by design
for seismic strengthening measures as modifications to correct or reduce seismic deficiency
identified during the evaluation procedure in first phase, this is known as retrofitting of thebuilding. This report is divided into three chapters.
Chapter one begins with introductions, objective, scope, methodology and limitations;
Chapter two outlines the data collection, assessment methodology, and survey findings.
Chapter three presents the summary and recommendations.
In addition, this report also includes ten annexes that provide supporting information on
issues discussed in the main report. These include details of intensity scale, damage grade of
the building, rapid visual screening, Turkish vulnerability score, building drawings, Nondestructive testing and photographs.
BNUS Annual Report-2010119March 2011
Objective

The main objective of the task is to evaluate the seismic safety of the proposed schoolbuilding with recommendations for increasing the seismic safety of the building.
Scope of Work

The scope of the work for assessment is as follows:i. Prepare as-built drawings of the building
ii. Conduct a survey to determine the structural characteristics of the buildingiii. Assess the structural and non-structural earthquake vulnerability of the building by
qualitative method
iv. Prepare the report explaining procedures and presenting findings and recommendation
Overall Methodology

The overall methodology adopted for this study is as follows:i. Reconnaissance of building structureii. Identification of building typology based on construction materials and structural systems
iii. Detailed visual survey of building which includes:•

Identification of strengths and deficiencies•

Identification of structural vulnerability factors: Plan and vertical irregularities,
vertical load path, configuration problems, lateral force resisting system, material
deterioration etc

iv. Evaluation of general earthquake performance of the building. The building performanceis evaluated based on the available fragility.
v. Summarization of findings and recommendation
The detailed description of each methodology for seismic vulnerability assessment is given in
the respective chapter.
Limitations

No specific details could be collected from the people involved in the design and constructionof the building. Hence, review of available drawings, visual inspection and nondestructive
tests were carried out to determine the building details and educated guess was done todetermine the expected performance of the building.

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ICUS Report 54

Effects of secondary or collateral hazards such as liquefaction, soil spreading, fire is notconsidered during the study.

Assessment of the Buildings
Qualitative and some quantitative structural assessment of the building are done based on
visual observation and review of drawings, design details observed at site during field visit.
Different seismic vulnerability factors are checked and expected performance of the building
is estimated for different intensities earthquakes. Different steps of the assessment process
and their outcomes are described in this section.
Descriptions of the schools

A. Siverdale Preparatory and Girls High School is located in ward no. 74 of Dhaka City
Corporation area. The street is named Rankin Street in Wari. It was established in
1985. It has around 1500 students.
B. Wari Girls Govt. Primary School is located in ward no. 77 of Dhaka City Corporation
area. It was established on 2002. It has around 200 students. The school has a single
main block
C. Salim Ullah Degree College is located at Rankin Street in Wari, Dhaka. Age of thebuildings is less than 30 years. It has around 1500 students. The school has two blocks.
One is administration office and another is academic building. Academic building wasinvestigated.
D. Graduate High School is located in ward no. 77 of Dhaka City Corporation area. It
was established on 1985. It has around 400 students. The school has a single main
block.

A

B

C and D(left)

Figure1: Location of School Building.
BNUS Annual Report-2010
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March 2011
Descriptions of the buildings

A. Following are the descriptions of the buildings based on prepared architectural
drawing and site observations. Site visit to the building was made on 30 October,
2010.
Owner
Location
G.P.S
Terrain TypeAge of Building
No of Stories
Plan configuration
Vertical Configuration
Position of the building block
Building Typology
Mortar Type
Total Plinth Area
Exterior Wall Thickness
Interior Wall Thickness
Foundation
Roof structure
Roof Shape
Designed and Supervised of the
Building

Wari, Dhaka
Flat
About 25 years
5 storey
Irregular
Regular
Free Standing
RC
Cement mortar.
2600 Sq. ft
5 inch.
5 inch.
Not Known
RCC
Flat

Earthquake-Resistant Element

No

Local hazard
Building Condition

Earthquake, Fire.
Average

Perspective view

Building Plan

Not Known

B. Following are the descriptions of the buildings based on prepared architectural
drawing and site observations. Site visit to the building was made on 31 October,
2010.
Owner
Location
G.P.S
Terrain TypeAge of Building
No of Stories
Plan configuration
Vertical Configuration
Position of the building block
Building Typology
Mortar Type
Exterior Wall Thickness
Interior Wall Thickness
Foundation

122

Wari, Dhaka
Flat
8 years
2storey
Regular
Regular
Free Standing
RC
Cement mortar.
5 inch.
5 inch.
Not Known

Perspective view
Toilet

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ICUS Report 54
Roof structure
Roof Shape
Designed and Supervised of
the Building

RCC
Flat

Building Plan

Not Known

Earthquake-Resistant Element

No

Local hazard
Building Condition

Earthquake, Fire.
Average

C. Following are the descriptions of the buildings based on prepared architectural
drawing and site observations. Site visit to the building was made on 31 October,
2010.
Owner
Location
G.P.S
Terrain TypeAge of Building
No of Stories

Wari, Dhaka
FlatLess than 30 years
3storey

Plan configuration

RegularVertical Configuration
Position of the building block
Building Typology
Mortar Type
Exterior Wall Thickness
Interior Wall Thickness
Foundation
Roof structure
Roof Shape
Designed and Supervised of the
Building

Regular
Free Standing
Mixed (RC and URM)
Cement mortar.
5 inch.
5 inch.
Not Known
RCC
Flat

Earthquake-Resistant Element

No

Local hazard
Building Condition

Earthquake, Fire.
Good

Perspective view

Building Plan

Not Known

D. Following are the descriptions of the buildings based on prepared architectural
drawing and site observations. Site visit to the building was made on 31 October,
2010.
Owner
Location
G.P.S
Terrain TypeAge of Building
No of Stories
Plan configuration
Vertical Configuration

Wari, Dhaka
Flat
25 years
3storey
Irregular
Regular

Perspective view

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Position of the building
Position of the building
block
block
Building Typology
BuildingType
Typology
MortarMortarType
Exterior Wall Thickness
ExteriorWall
WallThickness
Thickness
Interior
Interior Wall Thickness
Foundation
Foundation
Roof
structure
Roof
Roof structure
Shape
Roof
Shape
Designedand Supervised of
Designedand Supervised oftheBuildingthe
Building
Earthquake-Resistant
Earthquake-ResistantElement
Element
Local hazard
Local hazard
Building
Condition
Building Condition

Free Standing
Free Standing
RC
RC
Cementmortar.
Cement5 inch. mortar.
inch.
55inch.
5 inch.
Not
KnownNot Known
RCC
RCC
Flat
Flat
Not Known
Not Known
No
No
Earthquake, Fire.
Earthquake, Fire.
Average
Average

Building Plan
Building Plan

Building Typology Identification
Building Typology Identification

Identification of building typology was determined on the classification of building types in
Identificationbuilding
wasdeterminedclassificationof buildinginthe region as ofgiven
in thetypology
followingtable
1. From onthethevisualobservationand studytypesof thethe regiondrawings,
as giventhe
in buildings
the following
1. Fromthe visual observation and study of the
prepared
were table
identified
as followings:
prepareddrawings,
thebuildings
wereidentified
asfollowings:
Building-A: Reinforced Concrete Ordinary Moment Resisting Frame (Type 3)
Building-A: Reinforced
Reinforced Concrete
Concrete Ordinary
Ordinary Moment
Moment Resisting
Resisting Frame
Frame (Type(Type 3)
3)
Building-B:
Building-B:
Reinforced
Concrete
Ordinary
MomentResisting
Frame
(Type
3)
Building-C: Reinforced Concrete Ordinary Moment Resisting Frame (Type 3) with a portion
Building-C:ofType 2. Reinforced Concrete Ordinary Moment Resisting Frame (Type 3) with a portionof Type 2. Reinforced Concrete Ordinary Moment Resisting Frame (Type 3)
Building-D:
Building-D: Reinforced Concrete Ordinary Moment Resisting Frame (Type 3)
Table 1: Buildings Types in the Region
Table 1: Buildings Types in the Region
Building Types
in Region

Description

1

Adobe, stone inmud, brick-inmud (Low
Strength
Masonry).

Adobe Buildings: These are buildings constructed in sun-dried
bricks (earthen) with mud mortar for the construction of structural
walls.
Stone in Mud: These are stone-masonry buildings constructedusing dressed or undressed stones with mud mortar. These typesof buildings have generally flexible floors and roof.
Brick in Mud: These are brick masonry buildings with fired bricks
in mud mortar.

2

Brick in Cement,
Stone in Cement

These are brick masonry buildings with fired bricks in cement orlime mortar and stone-masonry buildings using dressed orundressed stones with cement mortar.

3
3

Reinforced
Concrete
Ordinary-

These are buildings with reinforced concrete frames andThese are buildings with reinforced concrete frames andunreinforced brick masonry infill in cement mortar. The thickness
unreinforced brick masonry infill in cement mortar. The thicknessof infill walls is full brick thick or even half brick.
of infill walls is full brick thick or even half brick.

No.

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MomentResisting-Frame
Buildings

4

Reinforced
Concrete
IntermediateMomentResisting-Frame
Buildings

These buildings consist of a frame assembly of cast-in-place
concrete beams and columns. Floor and roof framing consists ofcast-in-place concrete slabs. Lateral forces are resisted by
concrete moment frames that develop their stiffness throughmonolithic beam-column connections. These are engineeredbuildings designed without earthquake load or with old codes ordesigned for small earthquake forces.

5

Reinforced
concrete specialmoment-resistantframes (SMRF)

These buildings consist of a frame assembly of cast-in-place
concrete beams and columns. Floor and roof framing consists ofcast-in-place concrete slabs. Lateral forces are resisted by
concrete moment frames that develop their stiffness throughmonolithic beam-column connections. These buildings have joint
reinforcing, closely spaced ties, and special detailing to provide
ductile performance.

6

OthersMixed buildings like Stone and Adobe, Stone and Brick in Mud,
Brick in Mud and Brick in cement etc. are other building.

Fragility of the Identified Building Typology

The fragility or the seismic vulnerability of a building is the possible consequences to thebuilding due to the probable earthquake shaking. The fragility is expressed as the degree ofseverity of damage (Damage Grade) in a building during different earthquake intensities.
Normally, the buildings with similar structural systems and properties behave in similar
pattern during the earthquakes. Hence, generalized fragility functions (or curves) areavailable for different types of building. In Bangladesh case, fragility functions from Nepal,
India and Pakistan are utilized and verified with “European Macro-seismic Scale (EMS 98)”
http://www.gfz-potsdam.de/pb5/pb53/projekt/ems/core/ emsacor.htm. Damage grades ofdifferent building typologies in different intensities of earthquakes are extracted from suchfragility functions. Such damage grades for the identified Masonry Building, Reinforced
Concrete Ordinary Moment Resisting Frame Building and Reinforced Concrete Intermediate
Moment Resisting Frame building are given below in Tables 2 and 3 respectively.
The EMS is a unit to measure the intensity of earthquake in a particular area. The EMS is aqualitative measure of the actual shaking at a location during earthquake, and is assigned as
Roman Capital Numerals. It ranges from I (least perceptive) to XII (most severe). The
intensity scales are based on three features of shaking- perception by people and animals,
performance of buildings, and changes to natural surroundings. The detailed description ofIntensity Scale is given on Annex 1.

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Table 2: Fragility of the Masonry Building on Brick in Cement Mortar
Shaking Intensity
VII
VIII
IX
(EMS)
Damage
Weak
DG3
DG4
DG5
Grades for
Average
DG2
DG3
DG4
Different
Classes of
Good
DG1
DG2
DG3
Buildings
Table 2 shows that the weaker buildings of this category get damage degree of four (DG5) at
intensity IX where as good buildings of this category will suffer damage degree of two (DG3)at the same intensity. For the detail description of different damage grade of building refer
Annex 2.
Table 3: Fragility of the Reinforced Concrete Ordinary Concrete Moment Resisting
Frame
Shaking Intensity
VII
VIII
IX
(EMS)
DamageGrades forDifferent
Classes of
Buildings

Weak

DG2

DG3

DG4

Average

DG1

DG2

DG3

Good

-

DG1

DG2

The Table 3 shows that the weaker buildings of this category get damage degree of four
(DG4) at intensity IX where as good buildings of this category will suffer damage degree oftwo (DG2) at the same intensity. For the detail description of different damage grade ofbuilding refer Annex 2.
Identification of Vulnerability Factors

The general vulnerability of the building as identified by the use of generalized fragility
function needs to be modified based on the influence of different vulnerability factor existingin the building. The different vulnerability factors associated with particular type of building
are checked with a set of appropriate checklist from FEMA 310, "Handbook for the Seismic
Evaluation of Buildings" and Indian Standard Guidelines for Seismic Evaluation andStrengthening of Existing Buildings. The basic vulnerability factors are building system, plan
irregularities, vertical irregularities, lateral force resisting system, connections diaphragms etc.
Influence of Different Vulnerability Factors to the Seismic Performance of the Building
Based on the existence of different vulnerability factors as appearing in the surveyed
checklist following table (Table 4: Influence of Different Vulnerability Factors to the
Building) is completed to evaluate the final influence of different vulnerability factors on thefragility of the building.

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Table 4 : Influence of Different Vulnerability Factors to the Building
Increasing Vulnerability of the Buildingby different vulnerability factors
Vulnerability Factors
MediumHigh
Low
N/A
Not known

Building SystemPlanirregularities
Verticalirregularities

Lateral load
resisting system

Diaphragm

Connections

Geologic Site
OthersNumber of storey
Shape
Proportion in plan
Opening in wall
Position of opening
Load Path
Adjacent buildings
Mezzanines floors
Deterioration of concrete
Masonry units
Masonry joints
Cracks in infill walls
Unsupported wall length
TorsionDiaphragm continuity
Weak storey
Soft storey
Mass irregularity
Vertical geometricirregularity
Verticaldiscontinuities
Redundancy
Height to thickness ratio
Masonry lay up
Vertical reinforcement
Horizontal bands
Corner stitch
Gable band
Diagonal bracing
Diaphragm opening at walls
Plan irregularities
Diaphragm reinforcement at
opening
Wall anchorage
Transfer to walls
Lateral restrainers
Area History
Liquefaction
Slope Failure
Non Structural Components

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Reinterpretation of the Building Fragility Based on Observed Vulnerability Factors

The above completed table 4 shows that the influence of different vulnerability factors is
critical which makes the building to fall under "Average” category of the building typology.
Hence, the assessed building is an Average type of Reinforced Concrete Ordinary Concrete
Moment Resisting Frame
Table 5: Reinterpreted Fragility of the Building
ID
A
B
C
D

Building
Main
Block
Main
Block
Main
Block
Main
Block

Building Performance (EMS)
VII

VIII

IX

Average

DG1

DG2

DG3

Good

-

DG1

DG2

Average

DG1

DG2

DG3

Weak

DG2

DG3

DG4

The minimum requirement of the building is to provide life safety for its occupants. It may
not provide when the performance of building will be DG4 or DG5 during an earthquake.
Probable Performance of the Buildings at Different Intensities

The performance of the building in terms of vulnerability is given in Table 9 as per thequalitative assessment done above.

ID
A
B
C
D

Table 6: Probable performance of the building
Performance of the Building
Item
Building
EMS = VII
EMS =VIIIEMS = IX
Structural
Main Block
SlightModerate
DamageStructural
Very Low
SlightMain Block
DamageStructural
Main Block
SlightModerate
DamageStructural
Main Block
SlightModerate
High
DamageRapid Visual Screening
Rapid visual screening of buildings for potential seismic hazards, as described herein, originated in1988 with the publication of the FEMA 154 provided a “sidewalk survey” approach that enabled users
to classify surveyed buildings into two categories: those acceptable as to risk to life safety or thosethat may be seismically hazardous and should be evaluated in more detail by a design professional
experienced in seismic design.
Fundamentally, the final S score is an estimate of the probability (or chance) that the building will
collapse if ground motions occur that equal or exceed the maximum considered earthquake (MCE)
ground motions (the current FEMA 310 ground motion specification for detailed seismic evaluation

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of buildings). These estimates of the score are based on limited observed and analytical data, and theprobability of collapse is therefore approximate. For example, a final score of S = 0.2 implies there isa chance of 1 in 100.2, or 63% chance that the building will collapse if such ground motions occur.
RVS calculation sheet are attached in Annex 3.
Turkish Vulnerability Score
Current approaches in seismic vulnerability evaluation methods can be classified in three main groups
depending on their level of complexity. The first, most simple level is known as “Walkdown
Evaluation.” Evaluation in this first level does not require any analysis and its goal is to determine thepriority levels of buildings that require immediate intervention. Preliminary assessment
methodologies (PAM) are applied when more in-depth evaluation of building stocks is required. In
this stage, simplified analysis of the building under investigation is performed based on a variety ofmethods. These analyses require data on the dimensions of the structural and nonstructural elementsin the most critical story. The procedures by FEMA 310 (1998) Tier 2 and Ozcebe et al. (2003), later
complemented by Yakut et al. (2003) can be listed as the examples of preliminary survey procedures.
The procedures in third tier employ linear or nonlinear analyses of the building under consideration
and require the as-built dimensions and the reinforcement details of all structural elements. The
procedures proposed in FEMA 356 (2000), ATC 40 (1996), EUROCODE 8 (2004) and those by
Sucuoglu et al. (2004) and Park and Ang (1985) are examples of third level assessment procedures.
This report only presents the first two phase seismic vulnerability assessment. Calculation of first twolevel are attached in Annex 4.

Table7: Observed Performance Score Assignment
Observed Performance
None
Light
Moderate
SevereObserved Performance Score
100
80
50
0

Non Destructive TestingNon destructive testing is a wide group of analysis techniques used to evaluate the material
properties, position of materials without causing damage. To identify the steel rebar positionin structural component, Hilti PS 200 Ferro scan device is used. Ferro scan Screening results
is shown in Annex 5.

Summary
To evaluate seismic safety of Silverdale Preparatory and Girls High School at Wari, Dhaka,
the study had to base upon various assumptions because of the unavailability of the people
involved in design and construction of this building. Tables 8, 9 and 10 present results of thestudied building.

Table 8: Summary of Seismic Vulnerability Assessment of Building.
Building
Average type of reinforced concrete ordinary
Building typology-A
moment resisting frame building.

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Building-B

Vulnerability Factors to the
Building

Discontinuity of beams, strong beam- weakcolumn, Non structural components.

Probable structural
performance of the building

EMS VIIEMS VIIIEMS IX-Slight
Moderate
Average type of reinforced concrete ordinary
moment resisting frame building.
Discontinuity of beams, strong beam- weakcolumn, Non structural components.
EMS VIIEMS VIIIEMS IX-No
SlightAverage type of reinforced concrete ordinary
moment resisting frame building.
Discontinuity of beams, strong beam- weakcolumn, Non structural components.
EMS VIIEMS VIIIEMS IX
SlightModerate
Average type of reinforced concrete ordinary
moment resisting frame building.
Discontinuity of beams, strong beam- weakcolumn, Non structural components.
EMS VIIEMS VIIIEMS IX
SlightModerateHigh

Building typology
Vulnerability Factors to the
Building
Probable structural
performance of the building

Building-C

Building typology
Vulnerability Factors to the
Building
Probable structural
performance of the building

Building-D

Building typology
Vulnerability Factors to the
Building
Probable structural
performance of the building

Check
Rapid Visual Screening
Turkish Level 1
Turkish Level 2
Column Bar Spacing &CoverBeam Bar Spacing &CoverSlab Bar Orientation

Item
Building Use
Building Age

130

Table 9: Summary of Results.
Building Building Building A
B
C
High
Low
Low
Moderate
None
None
SevereLow
Moderate
Not
Not
SatisfiedSatisfied
NotSatisfiedSatisfiedSatisfied
Not
Not
SatisfiedSatisfiedSatisfied

Building D
Low
None
Sever
Not
Satisfied
NotSatisfied
NotSatisfied

Table 10: General Importance Factor
Building - A
Building - B
Building - C
Educational
Educational
Educational
25 yrs
8 yrs
Less than 30 yrs

Reference
Annex3Annex4
Annex4
Annex5Annex5Annex5

Building - D
Educational
25 yrs

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Visible Physical
Condition
Occupancy

Average

Good

Good

Poor

High

Low

High

High

Conclusions
Based on the assessment done above on the basis of the available information about thebuilding, the architectural and structural information from field visit, and implementation oflimited number of non-destructive field tests, it be expected that the assessed building is likely
to suffer moderate structural damage at large earthquakes of intensity IX.
According to Specialist’s judgment, Building A falls under moderate risk group, Building B
falls under Low risk group, Building C & Building D fall under High risk group. For last twobuildings, a non-compliance situation observed with respect to the Bangladesh National
Building Code that requires; “Structures should be able to resist moderate earthquakes
without significant damage”; and “Structures should be able to resist major earthquakes
without collapse”.

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Annex 1: Definitions of intensity degrees
Arrangement of the scale:a) Effects on humansb) Effects on objects and on nature (effects on ground and ground failure are dealt withespecially in Section 7)c) Damage to buildings

Introductory remark:The single intensity degrees can include the effects of shaking of the respective lower
intensity degree(s) also, when these effects are not mentioned explicitly.
I. Not felta) Not felt, even under the most favourable circumstances.
b) No effect.
c) No damage.
II. Scarcely felta) The tremor is felt only at isolated instances (<1%) of individuals at rest and in a specially
receptive position indoors.
b) No effect.
c) No damage.
III. Weaka) The earthquake is felt indoors by a few. People at rest feel a swaying or light trembling.
b) Hanging objects swing slightly.
c) No damage.
IV. Largely observeda) The earthquake is felt indoors by many and felt outdoors only by very few. A few people
are awakened. The level of vibration is not frightening. The vibration is moderate. Observers
feel a slight trembling or swaying of the building, room or bed, chair etc.
b) China, glasses, windows and doors rattle. Hanging objects swing. Light furniture shakes
visibly in a few cases. Woodwork creaks in a few cases.
c) No damage.
V. Stronga) The earthquake is felt indoors by most, outdoors by few. A few people are frightened andrun outdoors. Many sleeping people awake. Observers feel a strong shaking or rocking of thewhole building, room or furniture.
b) Hanging objects swing considerably. China and glasses clatter together. Small, top-heavy
and/or precariously supported objects may be shifted or fall down. Doors and windows swing
open or shut. In a few cases window panes break. Liquids oscillate and may spill from wellfilled containers. Animals indoors may become uneasy.
c) Damage of grade 1 to a few buildings of vulnerability class A and B.

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VI. Slightly damaginga) Felt by most indoors and by many outdoors. A few persons lose their balance. Many
people are frightened and run outdoors.
b) Small objects of ordinary stability may fall and furniture may be shifted. In few instances
dishes and glassware may break. Farm animals (even outdoors) may be frightened.
c) Damage of grade 1 is sustained by many buildings of vulnerability class A and B; a few ofclass A and B suffer damage of grade 2; a few of class C suffer damage of grade 1.
VII. Damaginga) Most people are frightened and try to run outdoors. Many find it difficult to stand,especially on upper floors.
b) Furniture is shifted and top-heavy furniture may be overturned. Objects fall from shelvesin large numbers. Water splashes from containers, tanks and pools.
c) Many buildings of vulnerability class A suffer damage of grade 3; a few of grade 4.
Many buildings of vulnerability class B suffer damage of grade 2; a few of grade 3.
A few buildings of vulnerability class C sustain damage of grade 2.
A few buildings of vulnerability class D sustain damage of grade 1.
VIII. Heavily damaginga) Many people find it difficult to stand, even outdoors.
b) Furniture may be overturned. Objects like TV sets, typewriters etc. fall to the ground.
Tombstones may occasionally be displaced, twisted or overturned. Waves may be seen onvery soft ground.
c) Many buildings of vulnerability class A suffer damage of grade 4; a few of grade 5.
Many buildings of vulnerability class B suffer damage of grade 3; a few of grade 4.
Many buildings of vulnerability class C suffer damage of grade 2; a few of grade 3.
A few buildings of vulnerability class D sustain damage of grade 2.
IX. Destructivea) General panic. People may be forcibly thrown to the ground.
b) Many monuments and columns fall or are twisted. Waves are seen on soft ground.
c) Many buildings of vulnerability class A sustain damage of grade 5.
Many buildings of vulnerability class B suffer damage of grade 4; a few of grade 5.
Many buildings of vulnerability class C suffer damage of grade 3; a few of grade 4.
Many buildings of vulnerability class D suffer damage of grade 2; a few of grade 3.
A few buildings of vulnerability class E sustain damage of grade 2.
X. Very destructivec) Most buildings of vulnerability class A sustain damage of grade 5.
Many buildings of vulnerability class B sustain damage of grade 5.
Many buildings of vulnerability class C suffer damage of grade 4; a few of grade 5.
Many buildings of vulnerability class D suffer damage of grade 3; a few of grade 4.
Many buildings of vulnerability class E suffer damage of grade 2; a few of grade 3.
A few buildings of vulnerability class F sustain damage of grade 2.
XI. Devastatingc) Most buildings of vulnerability class B sustain damage of grade 5.
Most buildings of vulnerability class C suffer damage of grade 4; many of grade 5.
Many buildings of vulnerability class D suffer damage of grade 4; a few of grade 5.
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Many buildings of vulnerability class E suffer damage of grade 3; a few of grade 4.
Many buildings of vulnerability class F suffer damage of grade 2; a few of grade 3.
XII. Completely devastatingc) All buildings of vulnerability class A, B and practically all of vulnerability class C are
destroyed.
Most buildings of vulnerability class D, E and F are destroyed. The earthquake effects havereached the maximum conceivable effects.

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Annex 2: Damage Grades of the Buildings (For Reinforced Concrete
Buildings)(Classification from European Macro-seismic Scale (EMS 98))
Classification of damage to buildings of reinforced concrete
Structural damage : No
Non-structural damage: Slight•

Grade 1: Negligible to slight damage

Grade 2: Moderate damage

Grade 3: Substantial to heavy damage

Grade 4: Very heavy damage•

Fine cracks in plaster over frame members or in walls at
the base.
Fine cracks in partitions and infills.

Structural damage : SlightNon-structural damage: Moderate• Cracks in columns and beams of frames and in structural
walls.
• Cracks in partition and infill walls; fall of brittle cladding
and plaster.
• Falling of mortar from the joints of wall panels.
Structural damage: Moderate
Non-structural damage: Heavy• Cracks in columns and beam column joints of frames atthe base and at joints of coupled walls.
• Spalling of concrete cover, buckling of reinforced bars.
• Large cracks in partition and infill walls, failure ofindividual infill panels.
Structural damage: Heavy
Non-structural damage: Very heavy• Large cracks in structural elements with compression
failure of concrete and fracture of rebars; bond failure ofbeam reinforced bars; tilting of columns.
• Collapse of a few columns or of a single upper floor.

Structural damage: very heavy•

Collapse of ground floor or parts (e.g. wings) of buildings.

Grade 5: Destruction

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Annex 3: Rapid Visual Screening
RVS SCORE-Building A
Seismic zone

Moderate

Building Type

C3
Presence of Vulnerability
Factors

Vulnerability Factors

Total
Score

Basic Score & Score Modifiers

Basic Score

3.2

3.2

Mid Rise (4 to 7 stories)

1

0.2

0.2

High Rise (> 7 stories)

0

0.4

0

Vertical Irregularity

1

-2

-2

Plan Irregularity

1

-0.5

-0.5

Pre-Code0-10

Post-Benchmark

0

N/A

0

Soil Type C

0

-0.6

0

Soil Type D

1

-1

-1

Soil Type E

0

-1.6

0

Total Score 'S'=

-0.1

Probability of collapse at Maximum Considered Earthquake

100%

Seismic zone
Building Type
Vulnerability Factors

RVS SCORE-Building B

Moderate
C3
Presence ofVulnerability Factors

Basic Score

Basic Score & Score Modifiers

Total
Score

3.2

3.2

Mid Rise (4 to 7 stories)

0

0.2

0

High Rise (> 7 stories)

0

0.4

0

Vertical Irregularity

0

-2

0

Plan Irregularity

0

-0.5

0

Pre-Code0-10

Post-Benchmark

0

N/A

0

Soil Type C

0

-0.6

0

Soil Type D

1

-1

-1

Soil Type E

0

-1.6

0

Total Score 'S'=
Probability of collapse at Maximum Considered Earthquake

136

2.2
1%

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RVS SCORE-Building C
Seismic zone

Moderate

Building Type

C3
Presence ofVulnerability Factors

Vulnerability Factors

Basic Score & Score Modifiers

Total
Score

3.2

3.2

Basic Score
Mid Rise (4 to 7 stories)

0

0.2

0

High Rise (> 7 stories)

0

0.4

0

Vertical Irregularity

0

-2

0

Plan Irregularity

0

-0.5

0

Pre-Code0-10

Post-Benchmark

0

N/A

0

Soil Type C

0

-0.6

0

Soil Type D

1

-1

-1

Soil Type E

0

-1.6

0

Total Score 'S'=

2.2

Probability of collapse at Maximum Considered Earthquake

Seismic zone
Building
Type
Vulnerability
FactorsRVS SCORE-Building D
Moderate
C3
Presence ofVulnerability
Factors

Basic Score & Score Modifiers

Total
Score

3.2

3.2

0

0.2

0

0

0.4

0

0

-2

0

1

-0.5

-0.5

0

-1

0

Basic Score
Mid Rise (4to 7 stories)
High Rise (>7 stories)
VerticalIrregularity
Plan
Irregularity
Pre-Code

1%

PostBenchmark
Soil Type C

0

N/A

0

0

-0.6

0

Soil Type D

1

-1

-1

Soil Type E

0

-1.6

0
Total Score 'S'=

1.7

Probability of collapse at Maximum Considered Earthquake

2%

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Annex 4: Turkish Level 1 and Level 2
Building A. Level 1
Turkish Level 1 Score
Building
ID
S1

Number of
Story

Zone
I

Zone
II

Zone
III

Soft
Story

Heavy
Overhang

Apparent
Quality

Short
ColumnPounding

5

80

90

115

-15

-15

-15

-5

-3

VSM

0

1

0

1

0

1

1

0

∑VSM X VS

0

90

0

-15

0

-15

-5

0

Remarks

PS

55

Moderate

Building A. Level 2
Turkish Level 2 Score
Building ID

S1

Number of
Story

Zon
e II

Soft
Stor
y

Heavy
OverhangApparent Quality

Short
ColumnPounding

Topog.
Effect
s

Plan
Irreg
.

Redundancy

SI

5

105

-15

-15

-15

-5

-3

-2

-5

-10

10

VSM

0

1

0

1

1

0

0

1

1

1

∑VSM X
VS

0

-15

0

-15

-5

0

0

-5

-10

10

Remarks

P
S

30

SevereBuilding B. Level 1
Turkish Level 1 Score
Building
ID
1

Number of
Story

Zone
I

Zone
II

Zone
III

Soft
Story

Heavy
Overhang

Apparent
Quality

Short
ColumnPounding

2

90

125

160

-5

-5

-5

-5

0

VSM

0

1

0

0

1

1

1

0

∑VSM X VS

0

125

0

0

-5

-5

-5

0

Remarks

PS

110

None

Building B. Level 2
Turkish Level 2 Score
Building
ID

1

Number of
Story

Zone
II

Soft
Story

Heavy
Overhang

Apparent
Quality

Short
ColumnPounding

Topog.
Effects

Plan
Irreg.

Redundancy

SI

2

130

0

-5

-5

-5

0

0

0

0

-5

VSM

0

0

1

1

1

0

0

0

1

0

∑VSM X VS

0

0

-5

-5

-5

0

0

0

0

0

Remarks

138

PS

80

Low

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ICUS Report 54

Building C. Level 1

Building
ID
1

Number of
Story

Zone
I

Zone
II

Turkish Level 1 Score
Heavy
Zone SoftOverhang
III
Story

3

90

125

160

-10

VSM

0

1

0

∑VSM X VS

0

125

0

Apparent
Quality

Short
ColumnPounding

-10

-10

-5

-2

0

0

1

0

0

0

0

-10

0

0

Remarks

PS
115

None

Building C. Level 2
Turkish Level 2 Score

Building
ID

1

Number of
Story

Zone
II

Soft
Story

Heavy
Overhang

Apparent
Quality

Short
ColumnPounding

Topog.
Effects

Plan
Irreg.

Redundancy

SI

3

125

-10

-5

-10

-5

-2

0

-2

0

-5

VSM

0

0

0

1

0

0

0

0

1

1

∑VSM X VS

0

0

0

-10

0

0

0

0

0

-5

Remarks

PS

75

Moderate

Building D. Level 1
Turkish Level 1 Score
Building
ID
1

Number of
Story

Zone
I

Zone
II

Zone
III

Soft
Story

Heavy
Overhang

Apparent
Quality

Short
ColumnPounding

3

90

125

160

-10

-10

-10

-5

-2

VSM

0

1

0

0

0

2

1

0

∑VSM X VS

0

125

0

0

0

-20

-5

0

Remarks

PS

100

None

Building D. Level 2
Turkish Level 2 Score
Building ID

1

Number of
Story

Zon
e II

Soft
Stor
y

Heavy
OverhangApparent
Quality

Short
Colum
n

Pounding

Topo.
Effect

Plan
Irre
g

Redunda
ncy

SI

3

125

-10

-5

-10

-5

-2

0

-2

0

-5

VSM

0

1

0

2

1

0

0

1

1

2

∑VSM X
VS

0

-10

0

-20

-5

0

0

-2

0

10

Remarks

PS

43

Severe139
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March 2011

Annex 5: Non-Destructive Testing
A. Detection of Steel Bar

Typical image Scan figure for column

Typical orientation of Steel bar in column

Typical image Scan for slab

Typical orientation of Steel bar in slab

B. Transverse Reinforcement Requirements
Column ID:

140

Building A: C1-GF

Column Dimension
Column Height (Clear Span)

C1
12
11
132

C2
12
ft
in

Longitudinal Bar Used
Diameter , D

5
0.625

#
bar
in

L0 ≥
Larger of C1 or C2
Clear Span/6
18"

12 in
22 in
18 in

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ICUS Report 54
Max. Value between tie (in aplane), hx
End Strip Length
Middle Strip length

6.5
22
88

in
in
in

Spacing Recommended for End Strip :S
Existing Spacing
Remark

3

in

10
Not
SatisfiedinSpacing Recommended for Middle Strip :S
3.75
Existing Spacing
RemarkCover depth ≥Existing min Depth
RemarkLongitudinal Bar Used
Diameter , D
Max. Value between tie (in aplane), hx
End Strip Length
Middle Strip length

3.75 in

Sx = 4+[(14-hx)/3]

6 in

in

6"
6 X Longitudinal Bar
Diameter, D

14
in
Not
Satisfied
Clear Cover Check
38.1
35
Not Satisfied

6 in
3.75 inmm
mm

Building A: C3-4F
C1
12
9.5
114

C2
12
ft
in

5
0.625

# bar
in

5
19
76

in
in
in

Spacing Recommended for End Strip :L0 ≥Larger of C1 or C2
Clear Span/6
18"

S

3

in

Existing Spacing

9

in

S≤
0.25 X Smaller of C1
or C2
6 X Longitudinal Bar
Diameter, D

Not Satisfied

Sx = 4+[(14-hx)/3]

Remark3 inS≤Column ID:
Column Dimension
Column Height (Clear Span)S≤
0.25 X Smaller of C1
or C2
6 X Longitudinal Bar
Diameter, D

Spacing Recommended for Middle Strip :
S
3.75

12 in
19 in
18 in

3 in
3.75 in
6 in

S≤
in

6"

6 in

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March 2011

10
in
Not
Satisfied
RemarkClear Cover Check
Cover depth ≥Existing min Depth
RemarkExisting Spacing

6 X Longitudinal Bar
Diameter, D

38.1
39Satisfied

3.75 inmm
mm

Building B: Transverse Reinforcement Requirements
Column ID:
C1-GF
C1

C2

L0 ≥

Column Dimension
Column Height (Clear Span)

11.5
9.5
114

16
ft
in

Larger of C1 or C2
Clear Span/6
18"

Longitudinal Bar Used
Diameter , D

5
0.625

# bar
in

Max. Value between tie (in a plane), hx

7in

End Strip Length
Middle Strip length

19
76

in
in

Spacing Recommended for End Strip :S
2.875
Existing Spacing
11
Remark

in
in

16
19
18

S≤
0.25 X Smaller of C1 or C2
6 X Longitudinal Bar Diameter, D

Not Satisfied

Sx = 4+[(14-hx)/3]

Spacing Recommended for Middle Strip :
S
3.75
in
Existing Spacing
12inRemarkNot Satisfied

in
in
in

2.87 in3.75 in
6

in

S≤
6"
6 X Longitudinal Bar Diameter, D

6 in
3.75 in

Overlay

RealDiam

X

Y

Coverage

mm

mm

in

in

in

C. Image Scan Results for Slab
Num

142

X

Y

Coverage

Diameter

Orientation

mm

mm

mm

1

74.3

244.3

40

#7

H

0

22

2.925

9.619

1.58

2

374.3

246.5

38

#3

H

0

10

14.736

9.704

1.501

3

104.4

502.9

32

#3

V

0

10

4.108

19.798

1.265

4

131.2

352.9

32

#4

V

0

13

5.164

13.892

1.265

5

135.3

224.3

35

#6

V

0

19

5.327

8.83

1.383

6

141

117.1

32

#3

V

0

10

5.551

4.612

1.265

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ICUS Report 54

7

302.5

524.3

28

#3

V

0

10

11.91120.641

1.107

8

339.3

117.1

32

#3

V

0

10

13.357

4.612

1.265

9

504.4

524.3

27

#3

V

0

10

19.85920.641

1.068

10

534

352.9

27

#3

V

0

10

21.02513.892

1.068

11

540.8

117.1

28

#3

V

0

10

21.292

4.612

1.107

D. Beam Reinforcement Requirements
Building A: Transverse Reinforcement Requirement for Beam (ACI 2002)
Beam height, h17in
Effective depth, d
14
inSmallest Longitudinal Bar Used
5#
Diameter, D
0.625
inHoop bar Used
3#
Hoop bar diameter, d1
End Strip Length, 2h
End Strip
Recommended S
Existing Spacing

0.375
34

Remark

-1st Trans. Bar from column face

-

in

7
5
Satisfied

in
in

38.1
46
Satisfiedmm
mm

RemarkMiddle Strip
Recommended S
Existing Spacing
RemarkClear Cover
Cover depth ≥Existing min Depth
Remark

in
in
S≤

3.5
-

in
in

d/4
8D

3.5 in
5 in

24d1
12"

9 in
12 in

1st Trans. Bar from column ≤ 2"
S≤
d/2

7 in

Building C: Transverse Reinforcement Requirement for Beam (ACI 2002)
Beam height, h25inEffective depth, d23

inSmallest Longitudinal Bar Used

5#

Diameter, D

0.625

in

Hoop bar Used

3#

Hoop bar diameter, d1

0.375

in

End Strip Length, 2h

50in

End Strip
Recommended S

S≤
5

in

d/4

5.8

in

BNUS Annual Report-2010143

March 2011
Existing Spacing

4.6

RemarkSatisfied

Existing 1st trans. bar from column face

in

4
Not
Satisfiedin

Recommended Spacing

11.5

in

Existing Spacing

9.5

in

RemarkSatisfied

Remark

8D

5

in

24d1

9

in

12"

12

in

1st Trans. Bar from column ≤ 2"

Middle Strip
S≤
d/2

12

in

Clear Cover
Cover depth ≥

38.1

mm

Existing min Depth30
NotSatisfiedmm

Remark144

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ICUS Report 54

Annex 6: Building Drawings

6'2'-5.0000"

2'-5.5000"

7'-6.0000"

3'2'-5.5000"

Y
13'-6.0000"

X
Figure: Ground Floor Plan of Building A.

ToiletFigure: Ground Floor Plan of Building B.

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March 2011

ToiletBridgeFigure: Ground Floor Plan of Building C.

Figure: Ground Floor Plan for Building D.

146

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Annex 7: Photographs

Soft Storey

1st -4th floor (Overhang)

Beam column junction

Ferro-Scan Testing
Building A

BNUS Annual Report-2010147

March 2011

Front view of the Buildings

Short Column

Broken glass of the window

Obstacle in stair
Building B

Verandah148

Beam
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ICUS Report 54

Building C

Crack in Beam

Poor Electrical Condition

Non Structural Components

Ferro-Scan Testing
Building D

BNUS Annual Report-2010

149

PART-VIII
MASON TRAINING PROGRAM

BANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Saidur Rahman
Mehedi Ahmed Ansary

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ICUS Report 54

MASON TRAINING PROGRAMME ON
MULTI HAZARD RESILIENT CONSTRUCTIONS
Duration: 02-06 December, 2010
Venue: IR Project Office, Sylhet.
Building Disaster Resilient and Safer communities Under
5th DIPECHO Action Plan
Organized byIslamic Relief worldwide Bangladesh
BANGLADESH NETWORK OFFICE FOR URBAN SAFETY (BNUS)
Bangladesh is a moderate seismic country in the world. Major earthquake have been occurredin Sylhet areas of Bangladesh in the past. Therefore, seismic resistant building construction inthese areas is mandatory for the building disaster resilient and safer communities. That’s why
the Islamic Relief Worldwide Bangladesh and Bangladesh Network office for urban safety(BNUS) arranged the five days mason Training on Multi Hazard Resilient Constructions inSylhet in order to make Building Disaster Resilient and Safer community from December 2
to December 6, 2010. The purpose of this training was to share knowledge with local masons
about seismic resistant building construction in Sylhet. Various topics of sustainable building
construction have been dicussed in this programme. We, two stuff of BNUS (Dr. Mehedi
Ahmed Ansary and Md. Saidur Rahman) and two trained masons of BUET (Md. Motiur
Rahman and Md. Khurshed Alam), participated the five days Training course. This training
was very significant to develop knowledge among the masons from the root level ofconstruction. A model building (10 feet length, 10 feet width and 10 feet height) has been
erected considering all seismic criterion. Stirrups and ties are bent 135° angle in both beam
and column. This criterion is very important according to seismic resilient building. Seismic
criteria for building construction are not considered most of the building in our country.
That’s why the message of following these criteria is spread among the masons who are
involved directly in any construction. Certificate for the successfully completion of training
have been issued by BNUS in this programme. In addition to this, the training on seismic
protected buildings has been arranged for professional engineers and house owners in anotherprogramme under Bangladesh Network Office for Urban Safety (BNUS). Some pictures of
the training session have been shown in Figure 1 and 2.

BNUS Annual Report-2010151

March 2011

Figure 1: Group Photo of Mason training program at IR Project Office, Sylhet

Making a stirrup

Training class at IR ProjectOpen discussion with local

officemason

Making 135° angle stirrup

Placing of stirrups in a

Arrangement of anchorbeam

reinforcement in beam andcolumnFigure 2: Mason training programme at Sylhet

152

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ICUS Report 54

MASON TRAINING PROGRAMME ON
MULTI HAZARD RESILIENT CONSTRUCTIONS
Duration: 03-08 October, 2010
Venue: IR Project Office, Netrokona.
Earthquake Resistant Building construction Under
European Commission
Organized byIslamic Relief worldwide Bangladesh
BANGLADESH NETWORK OFFICE FOR URBAN SAFETY (BNUS)
The Islamic Relief Worldwide Bangladesh and Bangladesh Network office for urban safety(BNUS) arranged the six days mason Training on Multi Hazard Resilient Constructions in
Netrokona in order to make Earthquake Resistant building Construction Under European
Commission from October 3 to October 08, 2010. We, three stuff of BNUS (Dr. Mehedi
Ahmed Ansary, Md. Saidur Rahman and Md. Qurban Ali) and two trained masons of BUET
(Md. Motiur Rahman and Md. Khurshed Alam), participated the six days Training course. To
demonstrate seismic protected building a model building (10 feet length, 10 feet width and 10
feet height) has been built considering all seismic criterion. Some photographs of mason
training at Netrokona have been shown in Figure 3.

Model building for mason training at

Open discussion with mason in Netrokona

Netrokona

BNUS Annual Report-2010
153

PART-IX
WORKSHOPS, SEMINARS AND TRAINING
COURSESBANGLADESH NETWORK OFFICE FORURBAN SAFETY (BNUS), BUET, DHAKA

Prepared By: Sharmin Ara
Mehedi Ahmed Ansary

BNUS Annual Report-2010

ICUS Report 54

Workshop on Fundamental concepts of fire fighting and formulation oflegislation regarding hazardous fire
A workshop on Fundamental Concepts of Fire Fighting and Formulation of Legislation
Regarding Hazardous Fire was held on January 20, 2011 at ITN center, BUET. This daylong workshop was organized by BUET- Japan Institute of Disaster Prevention and Urban
Safety (BUET-JIDPUS). The workshop was divided into two sessions and there were two
experts who gave lecturers on different issues regarding basic concepts of fire hazard, firefighting system, design standard, standard rules and regulation and laws practiced in
Bangladesh. The main lecturer of the workshop was Architect Tajuddin Ahmed Chowdhury
ana Dr. Md. Maksud Helali, Professor of Mechanical Engineering department, BUET.
Architect Tajuddin Ahmed Chowdhury mainly covered his lecture from National Fire
Protection Association (NFPA-2000). Forty participants took part in this workshop fromdifferent professional group. A research planner (Sharmin Ara) of BNUS participates in thisday long workshop. All participated members were come from different professional group
and academician. But especially this workshop was very helpful for the fire fighters of Fire
Service and Civil Defense (FSCD).

Inauguration session of theworkshopArchitect Tajuddin giving his
lectures on different terrible fireincidents in Bangladesh

Participants of the workshop
listening the lectures

Professor Helali giving his
lectures on basic concepts of fire
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March 2011

Lecture Course and Seminar on Urban building fire mitigation and safetyissues in Asian Mega cities: Bangladesh Chapter
Researchers of BNUS were participated in the lecture course and seminar in Bangladesh on‘Urban building fire mitigation and safety issues in Asian Mega cities: Bangladesh
Chapter’. This was a 3days long seminar held on 21st December to 23rd December 2010 at
Public Works Department, Dhaka. It was a collaborative research study of Tokyo Universityof Science (TUS); Building Research Institute, Japan; Bangladesh University of engineeringand Technology, American International University Bangladesh; Fire Service and Civil
Defense (FSCD); Ministry of Housing and Public Works, Bangladesh. Total no ofparticipants were fifty. This lecture course has been designed for the students of architectureand engineering disciplines, fire professionals and other concerned officials as well. In thislecture experts were gave emphasis on urban building fire issues. The seminar was divided
into number of sessions with some lectures rendered by experts and professionals on urban
fire mitigation and safety issues. Professor Sugahara Shinichi, Professor Kyoichi Kobayashi,
Professor Sugawa Osami gave lectures on different urban building fire and shared theirexperiences on this issue. At the end of the seminar certificate was awarded to eachparticipant by Professor Sugahara Shinichi of Tokyo University of Science.

Participants from different
professional groups

Certificates awarded to theparticipated professional groups

Workshop on Risk Resilient Infrastructures: Role of Education andTraining
All BNUS members were participated on the two day long workshop on Risk Resilient
Infrastructures: Role of Education and Training. This workshop was jointly organized by
156

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BUET- Japan Institute of Disaster Prevention and Urban Safety (BUET-JIDPUS),
Comprehensive disaster Management program (CDMP), UNDP and Ministry of Food andDisaster Management, Bangladesh on 13th and 14th November, 2010 at BUET, Dhaka. The
chief guest of the workshop was honorable minister of food and disaster management, Dr.
Muhammad Abdur Razzaque. Professor Dr. Mehedi Ahmed Ansary was the key note speaker.
This two day long workshop is divided into number of sessions. Different session focuses on
different issues like environmental issues, architectural issues, civil engineering issues, water
resources issues, planning issues etc. Professionals and experts of these issues presented
lectures on different session. A large number of participants (134) from different organization
took part in this workshop, among them academicians and professional groups were major inproportion. At the end of each session there was an open discussion session whereparticipants asked questions to the speaker of each presentation.

Inaugural session of theworkshopDr. Rezaur Rahman giving
welcome address

Part of the participants on
the workshop

One of the participants asking
questions to the speaker
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157

March 2011

Training course on GIS
A training course on Application of GIS for Natural Hazard and Risk Assessment washeld on 25th -29th September, 2010 at Dhaka. It was organized by Asian Disaster Prevention
Center (ADPC). Total number of participants was 35 and from BNUS a Research Planner(Sharmin Ara) took part in this training. The 5days long training course’s objective was todevelop basic skills on GIS analysis and application of GIS & Remote Sensing Techniques
for Disaster Risk Reduction among the trainee. The total training course has been divided
into five modules and each module provides practical knowledge on different issues and therespective trainer assigned hands on exercise to the all participants. This course was designed
to assist disaster management practitioners to enable them to use GIS. On the last day of the
training, participants received certificates for the completion of course.

Expert from AIT giving lectures on different
satellite and image processing

Participants doing an assigned
class work
158

Participants of the training course
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