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COMPARISON ON THE EFFECT OF EARTHQUAKE AND WIND LOADS ON
THE PERFORMANCE OF REINFORCED CONCRETE BUILDINGS
SUHANA BINTI SURADI
A thesis submitted in fulfilment of the
requirements for the award of the degree of
Master of Engineering (Structures)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
DECEMBER 2007
iii
For my beloved mother and father
iv
ACKNOWLEDEMENTS
I wish to express my sincere appreciation to my supervisor, Assoc. Prof. Dr.
Azlan Adnan from the Faculty of Civil Engineering, Universiti Teknologi Malaysia for
his guidance, advices and motivation. Without his continued support and interest, this
thesis would not be the same as what have been presented here.
Special thanks to the engineers of Cawangan Pakar dan Kejuruteraan Awam,
Public Work Department in Kuala Lumpur for the collaboration to achieve the goals of
my studies. All staff at state and district branches of Public Work Department
(Peninsular, Sabah and Sarawak) also deserve special thanks for providing the building
data and assistance during the site visit.
My sincere appreciation also extends to all my colleagues of SEER members;
Kak Ana, Sophia, Kak Jati, Rozaina, Abang Hendry, Meldi, Lami, and En. Rosaidi for
being a part of my family and friends for all these years.
v
ABSTRACT
In the year of 2004 and 2005, tremors from the Sumatran earthquakes had brought safety concerns to the publics, government authorities, engineers and researchers especially when the tremors are felt frequently in Malaysia and no earthquake design had been taken into practices. This study addresses the effects of earthquake and wind loads on the performance of reinforced concrete buildings in Malaysia by evaluating the adequacy of the building design capacity. This study investigated seven existing buildings from West and East Malaysia. The buildings were categorised as medium and high-rise reinforced concrete moment resisting frames. The UBC-97, CP3:1972 and the MS 1553:2002 are used as the design codes in determining the lateral loads from earthquake and wind. The design capacity calculation for the frames was based on BS 8110. There are five types of analyses adopted; (i) Free Vibration Analysis (FVA), (ii) Earthquake Static Equivalent Analysis (ESEA), (iii) Static Wind Analysis (SWA), (iv) Earthquake Dynamic Response Spectrum Analysis (EDRSA) and (v) Earthquake Dynamic Time History Analysis (EDTHA). Results from FVA showed that five out of seven buildings produced high dynamic amplification factor in the range of 2.01 to 5.16. These values show that local earthquake events produce dynamic effect to the buildings due to characteristic of the earthquake and the similarity between building’s and earthquake’s frequencies. From this study the ESEA normally produced larger lateral design load than that from the SWA and EDRSA. ESEA also result in larger base shear and deformation response includes greater lateral displacement and inter-storey drift in the buildings. However, the performances of buildings were generally deemed unsatisfactory under SWA, ESEA and EDRSA which design capacity of shear force at beam element and axial load at column element were exceeded. Based on storey drift response from ESEA and EDTHA, there are potential failures for the medium rise buildings at lower storey levels. While for high-rise buildings, the failures can potentially occur at higher storey levels. The inter-storey drifts indicator indicates that only the non-structural elements of the buildings would be possibly affected. However, based on Park and Ang Overall Damage Index, the results show that the maximum overall damage may reach up to 0.11 at 0.20g of earthquake intensity which indicates a moderate damage level where extensive large crack and spalling of concrete in weaker elements may occur.
vi
ABSTRAK
Pada tahun 2004 dan 2005 gegaran daripada gempa bumi di Sumatera telah meningkatkan tahap kesedaran orang ramai, pihak kerajaan, para jurutera dan para penyelidik tentang tahap keselamatan bangunan di Malaysia terutamanya apabila gegaran tersebut kian dirasai dan beban gempa bumi belum pernah diambil kira dalam reka bentuk. Kajian ini tertumpu kepada kesan beban gempa bumi dan beban angin terhadap prestasi bangunan konkrit bertetulang di Malaysia dengan mengenalpasti tahap keupayaan rekabentuk bangunan yang selamat. Kajian ini melibatkan tujuh buah bangunan termasuk di Malaysia Barat dan Timur. Bangunan-bangunan ini dikategorikan sebagai bangunan sederhana tinggi dan bangunan tinggi jenis kerangka rintangan momen konkrit bertetulang. Kod amalan rekabentuk UBC-97, CP3:1972 dan MS 1553: 2002 digunakan dalam menentukan beban rekabentuk gempa bumi dan angin. Pengiraan keupayaan rekabentuk untuk setiap kerangka bangunan adalah berdasarkan BS 8110. Terdapat lima jenis analisis yang digunakan iaitu (i) Analisis Getaran Bebas (AGB), (ii) Analisis Gempa Bumi Statik (AGS), (iii) Analisis Angin Statik (AAS), (iv) Analisis Spektra Gerak Balas Dinamik (ASGD), dan (v) Analisis Sejarah Masa Dinamik (ASMD). Keputusan daripada AGB menunjukkan lima daripada tujuh bangunan menghasilkan faktor pembesaran dinamik yang tinggi iaitu antara 2.01 hingga 5.16. Nilai ini menunjukkan bahawa siri gempa bumi tempatan menghasilkan kesan dinamik kepada bangunan-bangunan tersebut kesan dari prilaku gempa bumi dan kesamaaan antara frequensi bangunan dan gempa bumi tersebut. Hasil kajian ini menunjukkan bahawa AGS biasanya menghasilkan beban sisi rekabentuk yang lebih besar berbanding AAS dan ASGD. AGS juga menghasilkan ricih asas dan gerak balas ubah bentuk yang lebih besar termasuk anjakan sisi dan anjakan nisbi antara aras bangunan. Walau bagaimanapun, prestasi bangunan-bangunan tersebut secara keseluruhannya tidak selamat di bawah AGS, AAS dan ASGD dimana nilai daya ricih di rasuk dan daya paksi di tiang telah melebihi keupayaan rekabentuk elemen tersebut. Berdasarkan parameter anjakan nisbi antara aras untuk AGS dan ASMD menunjukkan bahawa potensi berlaku kegagalan struktur untuk bangunan sederhana tinggi adalah di aras bangunan yang lebih rendah manakala untuk bangunan tinggi potensi kegagalan akan berlaku di aras bangunan yang lebih tinggi. Keputusan ini menunjukkan bahawa hanya elemen bukan struktur akan mengalami kesan kerosakan. Walau bagaimanapun, berdasarkan Indeks Kerosakan Keseluruhan Park dan Ang, hasil kajian menunjukkan bahawa tahap kerosakan keseluruhan maksimum boleh mencecah sehingga 0.11 pada gempa bumi berintensiti 0.20g. Tahap kerosakan ini adalah sederhana yang mana keretakan besar secara menyeluruh dan kekopakkan konkrit di kawasan elemen yang lemah akan berlaku.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xiii
LIST OF FIGURES xvi
LISTOF SYMBOLS xxiii
LIST OF APPENDICES xxix
1 INTRODUCTION 1
1.1 General
1.2 Objectives
1.3 Scope of Work
1.4 Research Methodology
1.5 Organisation of Thesis
1
2
3
4
5
viii
2 LITERATURE REVIEW 8
2.1 Introduction
2.2 Lateral Load on Building
2.3 Wind Flow in Malaysia
2.4 Wind Design Provision
2.5 Seismic Design Provision
2.6 Development of Seismic Hazard Map in Malaysia
2.7 Seismic Design Practice in Malaysia
2.8 Case Study on Performance of Existing Building in
Malaysia
2.9 Building Response
2.9.1 Drift Limitation
2.9.2 Lateral Stability
2.10 Performance Based Seismic Engineering
2.10.1 Performance Level Definitions
2.11 Vulnerability Study of High-rise Buildings
2.12 Closing Remarks
8
8
11
13
15
17
25
27
30
30
32
34
34
40
44
3 THEORETICAL BACKGROUND 45
3.1 Introductory Remarks
3.2 Wind Forces
3.2.1 Design Wind Speed
3.2.1.1 Basic Wind Speed
3.2.1.2 Topography Factor
3.2.1.3 Factor from Ground
Roughness, Building Size and
Height above Ground
3.2.2 Dynamic Wind Pressure
3.3 Earthquake Lateral Forces
45
45
46
46
47
47
49
51
ix
3.3.1 Design Base Shear
3.3.2 Seismic Dead Load, W
3.3.3 Building Period, T
3.3.4 Seismic Importance Factor, I
3.3.5 Structural System Coefficient, R
3.3.6 Seismic Zone Factor, Z
3.3.7 Seismic Coefficients Cv and Ca
3.3.8 Soil Profile Type S
3.3.9 Seismic Sources Type A, B and C
3.3.10 Near Sources Factors Na and Nv
3.4 SAP 2000 Software Application
3.4.1 Eigenvector Analysis
3.4.2 Modal Stiffness and Mass
3.4.3 Participation Factors
3.4.4 Participating Mass Ratios
3.4.5 Response-Spectrum Analysis
3.5 Linear Static and Dynamic Response of Structure
3.5.1 Response of Harmonic Motion
3.5.2 Lateral Response of Structure
3.5.2.1 Drift
3.6 IDARC-2D Application
3.6.1 Structural Element models
3.6.1.1 Column Element
3.6.1.2 Beam Element
3.6.2 Hysteretic Rules
3.6.2.1 Three Parameter Park Model
3.6.2.2 Bilinear Hysteretic Model
3.6.3 Analysis Module
3.6.4 Nonlinear Dynamic Analysis
3.6.5 Park & Ang Damage Model
3.7 Closing Remaks
51
52
53
54
54
54
58
58
58
61
61
62
63
63
64
65
66
66
68
68
69
70
71
72
74
75
77
78
78
79
81
x
4 MODELING TECHNIQUE 82
4.1 Introductory Remarks
4.2 Building Description
4.2.1 Kuarters Kelas G Kudat
4.2.2 Kuarters Bomba Kelas F Miri
4.2.3 Hospital Besar Kota Bharu
4.2.4 Mahkamah Labuan
4.2.5 Jabatan Pendaftaran Negara
4.2.6 Komplek Mahkamah Tinggi Kuala
Terengganu
4.2.7 Blok 3B Pangsapuri Parcel 3
4.3 Geometry
4.4 Structural Elements
4.5 Material properties
4.6 Loadings
4.6.1 Gravity Load
4.6.2 Lateral Load
4.6.2.1 Static Wind Load
4.6.2.2 Static Equivalent Earthquake
4.6.2.3 Earthquake Response Spectra
4.6.2.4 Earthquake Time History
4.7 Non-linearity Properties
4.8 Load Cases
4.9 Basic modeling Assumption
82
83
84
85
86
87
89
90
91
93
94
103
104
104
104
105
105
106
109
110
111
112
xi
5 RESULT AND DISCUSSION 113
5.1 Introductory Remarks
5.2 Result of Modal Analysis
5.2.1 Mode Shapes
5.2.2 Time Period
5.2.3 Dynamic Magnification
5.3 Performance of Static and Dynamic Linear
Analysis
5.3.1 Base Shear
5.3.2 Displacement
5.3.3 Inter-storey Drift
5.3.4 Estimate of Demand and Capacity
5.3.5 Maximum Forces and Moment
Resultant
5.3.5.1 Axial
5.3.5.2 Shear
5.3.5.3 Moment
5.4 Performance of Dynamic Non-linear Analysis
5.4.1 Modal Analysis
5.4.2 Maximum Response
5.4.2.1 Storey Drift
5.4.3 Damage Analysis
5.4.4 Damage Patterns
5.4.5 System Damage Index
5.4.6 Vulnerability Study
5.5 Closing Remarks
5.5.1 Free Vibration Analysis
5.5.2 Performance of Static and Dynamic
Linear Analysis
113
113
114
119
121
124
125
128
133
135
138
139
140
140
156
156
159
159
163
163
172
177
179
179
179
xii
5.5.3 Performance of Dynamic Non-linear
Analysis
180
6 SUMMARY, CONCLUSION &
RECOMMENDATION
182
6.1 Summary
6.2 Conclusion
6.2.1 General
6.2.2 Free Vibration Analysis
6.2.3 Comparison between the Wind and
Earthquake Analysis
6.2.4 Comparison between the Linear and Non-
Linear Analysis
6.3 Recommendation
182
184
184
185
185
186
188
REFERENCES 190
APPENDICES
xiii
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Modified Beaufort scale (Sparks, 2003) 12
2.2 The common code provision for wind load 14
2.3 Base shear design for various codes of practice in America 16
2.4 Modified Mercalli Intensity (MMI) Scale (Richter, 1985) 19
2.5 Performance of existing high-rise buildings in Malaysia 28
2.6 Performance of residential buildings (Norhayati, 2003) 28
2.7 Base shear (kN) of Petronas Twin Tower (KLCC) under
wind and earthquake load (Tan, 2002).
29
2.8 Definition structural performance (Hamburger, 1997) 36
2.9 Structural Performance Levels and Damage1—Vertical
Elements (FEMA 273, Table 2-4)
38
2.10 Damage Control and Building Performance Levels (FEMA
273, Table 2-3)
39
2.11 Interpretation of overall damage index (Park et al., 1986) 40
2.12 Maximum global demand obtained from inelastic time-
history analyses (Mwafy et al. , 2004)
43
2.13 Local yielding observed from inelastic time-history
analyses ( Mwafy et al. , 2004)
44
3.1 Ground roughness, building size and height above ground,
factor S2 (Table 3: CP3: Chapter V: 1972)
49
xiv
3.2 Seismic Importance Factor (UBC-97) 55
3.3 Structural Systems (UBC-97) 57
3.4 Seismic coefficient Cv (UBC-97) 59
3.5 Seismic coefficient Ca (UBC-97) 59
3.6 Soil profile types (UBC-97) 60
3.7 Seismic sources type (UBC-97) 60
3.8 Near-sources factor Na (UBC-97) 61
3.9 Near-sources factor Nv (UBC-97) 61
4.1 Details of Kuarters Kelas G Kudat modal frame 95
4.2 Details of Kuarters Kelas F Miri modal frame 96
4.3 Details of Hospital Besar Kota Bharu modal frame 97
4.4 Details of Mahkamah Syariah Labuan modal frame 98
4.5 Details JPN Putrajaya modal frame 100
4.6 Details of Mahkamah Persekutuan Kuala Terengganu
modal frame
101
4.7 Details of Blok 3B Pangsapuri Putrajaya modal frame 103
4.8 Design wind pressure for wind velocity of 20m/s and 50m/s 105
4.9 Design base shear of buildings for ground acceleration
0.05g and 0.20g
107
4.10 Hysteretic modeling rules parameters 110
4.11 Load cases applied in the analysis study 111
5.1 Time period of modal frames based on different analysis. 120
5.2 Dynamic characteristics of the buildings 122
5.3 The natural period of Sumatra’s earthquake in local site
locations
122
xv
5.4 The natural period of East Malaysia’s earthquake in local
site locations
123
5.5 Dynamic magnification for buildings in Peninsular
Malaysia
123
5.6 Dynamic magnification for buildings in East Malaysia 124
5.7 Base shear generated by wind load and earthquake load 126
5.8 Inter-storey drift index under earthquake static equivalent
analysis at 0.2g ground acceleration
135
5.9 Design capacities on beam and column element based on
BS 8110.
139
5.10 Inter-storey drift index of modal frames used THA at 0.2g 162
5.11 Summarization of first yielding point for all buildings 171
5.12 Storey damage index of each building at 0.2g earthquake
intensity
173
5.13 Overall damage index of each building 176
5.14 The vulnerability study of structure building through
damage index under El-Cento earthquake
178
xvi
LIST OF FIGURES
FIGURE NO. TITLE PAGE
1.1 Methodology and organisation of the thesis 7
2.1 Comparison between design procedure against wind and
earthquake (Gould et al., 1980)
10
2.2. Basic wind speed zone map for Peninsular Malaysia
(MS 1553, 2002)
15
2.3 Seismic design provisions from other countries 18
2.4 Maximum observed earthquake intensity in Peninsular
Malaysia from 1805 to 1983 (MMS, 1994)
21
2.5 Maximum observed earthquake intensity in Sabah and
Sarawak from 1884 to 1983 (MMS, 1994)
21
2.6 Maximum observed earthquake intensity in Peninsular
Malaysia from 1805 to 1993 (MMS, 1994)
22
2.7 Maximum observed earthquake intensity in Sabah and
Sarawak from 1875 to 1993 (MMS, 1994)
22
2.8 Peak Ground Acceleration (PGA) contour based on
deterministic method (Azlan, et al., 2002)
23
2.9 Peak Ground Acceleration (PGA) map at 10% PE in 50
years on rock site conditions for the Peninsular Malaysia
(TR=500year), (Azlan et al., 2003)
24
2.10 Peak Ground Acceleration (PGA) map at 2% PE in 50
years on rock site conditions for the Peninsular Malaysia
24
xvii
(TR=2500year), (Azlan et al., 2003)
2.11 Spectral accelerations used in the seismic design of the
Penang bridge (Ramli, 1986)
25
2.12 Response spectrum at the surface of Penang (Azlan et
al., 2003)
26
2.13 Response spectrum at the surface of Kuala Lumpur
(Azlan et al., 2003)
27
2.14 Plan of the 54-storey tower describing the lateral force
resisting systems
41
2.15 The frame systems in the longitudinal and transverse
directions
41
3.1 A Statistical factor S3 (CP3: Chapter V: 1972) 50
3.2 Variation of predominant period at rock outcrops with
magnitude and distance. (Seed et al., 1969)
66
3.3 Dynamic magnification factor for structure (Chopra,
2002)
67
3.4 Definition of drift (Farzad, 2001) 69
3.5 Control parameters for the three parameter hysteretic
model (Valles et al., 1996)
75
3.6 Influence of degrading parameters on the hysteretic
behavior (Valles et al., 1996)
76
3.7 The branches of the hysteretic model and typical
hysteretic curves (Valles et al., 1996)
77
4.1 Configuration of Kuarters Division 1 & 2 Kudat
building: (a) Elevation view, (b) Plan view with selected
frame, (c) Building frame
84
4.2 Configuration of Kuarters Kelas G for Bomba Miri 86
xviii
building: (a) Front view, (b) Elevation view, (c) Plan
view with selected frame, (d) Building frame
4.3 Configuration of Hospital Besar Kota Bharu building:
(a) Lay out plan, (b) Elevation view, (c) Plan view with
selected frame, (d) Building frame
87
4.4 Configuration of Komplek Mahkamah Labuan building:
(a) Front view, (b) Elevation view, (c) Plan view with
selected frame, (d) Building frame
88
4.5 Configuration of Jabatan Pendaftaran Negara (JPN)
building: (a) Lay out plan, (b) Elevation view, (c) Plan
view with selected frame , (d) Building fame
89
4.6 Configuration of Komplek Mahkamah Tinggi Kuala
Terengganu building: (a) Plan view, (b) Elevation view,
(c) Plan view with selected frame, (d) Building frame
91
4.7 Configuration of Blok 3B Pangsapuri Parcel 3 building:
(a) Lay out plan, (b) Conner view, (c) Rear view, (d)
Building fame
92
4.8 Configuration of Kuarters Division II & III Kudat modal
frame (a) Frame elevation, (b) Column C1, and (c)
Beam B1
94
4.9 Configuration of Kuarters Kelas F Miri modal frame (a)
Frame elevation, (b) Column C1, (c) Column C2, and
(d) Beam B1
95
4.10 Configuration of Hospital Besar Kota Bharu modal
frame (a) Frame elevation, (b) Column C1, and (b)
Beam B1
96
4.11 Configuration of Mahkamah Syariah Labuan modal
frame (a) Frame elevation, (b) Column 1, (c) Column 2,
97
xix
(d) Beam 1, (e) Beam 2, and (f) Beam 3
4.12 Configuration of JPN Putrajaya modal frame (a) Frame
elevation, (b) Column C1, and (c) Beam B1
99
4.13 Configuration of Mahkamah Persekutuan Kuala
Terengganu modal frame (a) Frame elevation (b)
Column C1, (c) Column C2, (d) Beam B1, (e) Beam
B2, and (f) Beam B3
100
4.14 Configuration of Blok 3B Pangsapuri Putrajaya modal
frame (a) Frame elevation, (b) Column C1, (c) Column
C2, (d) Beam B1, and (e) Beam B2
102
4.15 Response Spectra (RS) applied on structural buildings
based on UBC 97
108
4.16 Time history function of El-Centro’s ground
acceleration for intensity 0.35g
109
5.1 Mode shape and time period of Kuarters Kudat building 115
5.2 Mode shape and time period of Kuarters Miri building 116
5.3 Mode shape and time period of Hospital Besar Kota
Bharu building
116
5.4 Mode shape and time period of Mahkamah Labuan building
117
5.5 Mode shape and time period of Jabatan Pendaftaran
Negara Putrajaya building
117
5.6 Mode shape and time period of Mahkamah Kuala
Terengganu building
118
5.7 Mode shape and time period of Block 3B Pangsapuri
Putrajaya building
118
5.8 Displacement and inter-storey drift on Kuarters Kudat 131
xx
5.9 Displacement and inter-storey drift on Kuarters Miri 131
5.10 Displacement and inter-storey drift on Hospital Besar
Kota Bharu
131
5.11 Displacement and inter-storey drift on Mahkamah
Labuan
132
5.12 Displacement and inter-storey drift on Jab. Pendaftaran
Negara Putrajaya
132
5.13 Displacement and inter-storey drift on Mahkamah
Kuala Terengganu
132
5.14 Displacement and inter-storey drift on Block 3B
Pangsapuri Putrajaya
133
5.15 Wind and earthquake demand-capacity applied on
structure
137
5.16 Maximum stress resultant under wind load at Kuarters
Division II & III Kudat
142
5.17 Maximum stress resultant under earthquake load at
Kuarters Division II & III Kudat
143
5.18 Maximum stress resultant under wind load at Kuarters
Miri
144
5.19 Maximum stress resultant under earthquake load at
Kuarters Miri
145
5.20 Maximum stress resultant under wind load at Hospital
Besar Kota Bharu
146
5.21 Maximum stress resultant under earthquake load at
Hospital Besar Kota Bharu
147
5.22 Maximum stress resultant under wind load at Mahkamah
Labuan
148
xxi
5.23 Maximum stress resultant under earthquake load at
Mahkamah Labuan
149
5.24 Maximum stress resultant under wind load at Jabatan
Pendaftaran Negara Putrajaya
150
5.25 Maximum stress resultant under earthquake load at
Jabatan Pendaftaran Negara Putrajaya
151
5.26 Maximum stress resultant under wind loa1d at
Mahkamah Kuala Terengganu
152
5.27 Maximum stress resultant under earthquake load at
Mahkamah Kuala Terengganu
153
5.28 Maximum stress resultant under wind load at Block 3B
Pangsapuri Putrajaya
154
5.29 Maximum stress resultant under earthquake load at
Block 3B Pangsapuri Putrajaya
155
5.30 Mode shapes and time periods of reinforced concrete
building frames used in IDARC program
157
5.31 Inter-storey drift of reinforced concrete building frames
under various intensity of El-Centro earthquake.
160
5.32 DSF under 0.05g, 0.10g, 0.15g and 0.20g earthquake
intensity for Kuarters Kudat building
164
5.33 DSF under variety earthquake intensity for Kuarters
Miri building
165
5.34 DSF under various earthquake intensity for Hospital
Besar Kota Bharu building
166
5.35 DSF under various earthquake intensity for Mahkamah
Labuan building
167
5.36 DSF under various earthquake intensity for JPN 168
xxii
Putrajaya building
5.37 DSF under various earthquake intensity Mahkamah
Kuala Terengganu
169
5.38 DSF under various of earthquake intensity Block 3B
Pangsapuri Putrajaya buildings
170
xxiii
LIST OF SYMBOLS
Ac - Area of the compressive reinforcing bars
At - Area of the tensile reinforcing bars
b - Clearance in window frame
β - Model constant parameter
β - Frequency ratio
C - Proportional damping matrix
C - Structural damping
[ ]C - Viscous matrix of the structure
c - Factor to amplify the curvature due to inelasticity of the
concrete
Ca - Seismic coefficient depend on soil region
ccorr - Correction coefficient (usually taken as one)
Cr - Critical damping
Cv - Seismic coefficient depend on soil region
D - Dynamic magnification factor
d - Shear drift
d - Depth to rebar in inches.
dc - Cover depth for compression bars
δ - Inter-storey drift index
xxiv
δi - Static lateral displacement at level i due to the forces Fi
computed on a linear elastic basis
δm - Maximum experienced deformation
δu - Ultimate deformation of the element
Δa - Allowable inelastic storey displacement
Δi - Lateral displacement
Δtop - Overall drift
{ }FΔ - Vector of applied load increments
{∆Ferr } - Vector with the unbalanced forces in the structure
{∆PV },
{∆PFR},
{∆PHY}, and
{∆PIW}
- Restoring forces from viscous dampers, friction dampers,
Hysteretic dampers and infill panels respectively
{ }uΔ - Vector of unknown nodal displacement increments
{∆u}, {∆ u& },
and {∆u&& }
- Incremental vectors of displacement velocity and
acceleration in the structure respectively
ghx&&Δ and
gvx&&Δ
- Increment in the horizontal and vertical ground
accelerations
εc and 'cε - Maximum compression and tension strains in the concrete
ε0 - Strain at maximum strength of the concrete
yε - Strain at yield stress of steel
'cf - Concrete strength in ksi
Fi - Seismic lateral force at Level i
xxv
Ft - Force at the top
Fx - Lateral force at level x
fxn, fyn, fzn - The participation factors
Φ - Matrix of corresponding eigenvectors
g - Acceleration due to gravity
H Height of building
h - Height of wall or cladding unit
h - Overall height of structure
h - Height of the section
HBD - Ductility-based strength degradation
HBE - Energy control strength
HC - Stiffness degradation
hi - Floor to floor of the structure
HS - Slip or crack closing parameter
hx, hi - Height in feet above the base at level x and i respectively
I - Seismic importance factor
Ig - Gross section
IBILINEAR - Vertex oriented model
nϕ or φn - Mode shape
K - Stiffness matrix
k - Coefficient for various units in the code of CP3: Chapter 5
k’ - Neutral axis parameter (similar to k).
[ ]tK - Tangent stiffness matrix
xxvi
{Lh} and {Lv} - Allocation vectors for the horizontal and vertical ground
accelerations
λi - Energy weighting factors
M - Diagonal mass matrix
[ ]M - Lumped mass matrix of the structure
+crM and −
crM - Positive and negative cracking moments
+uM and −
uM - Positive and negative ultimate moments
mx, my, mz - Unit acceleration loads
Mx, My, Mz - Total unrestrained masses acting in the X, Y and Z
direction
My - Yield moment
+yM and −
yM - Positive and negative yield moments
N - Numbers of stories
N - Axial load in kips
n - Number of floors
Na - Near sources factor
Nv - Near sources factor
Ω2 - Diagonal matrix of eigenvalues
P y - Yield strength of the element
q - Dynamic wind pressure
θr - Recoverable rotation when unloading
θu - Ultimate rotation capacity of the section
θM - Maximum rotation attained during the loading history
xxvii
S1 - Design wind speed factors (topography factor)
S1 - Maximum considered earthquake spectra response
acceleration at a 1 second period
S2 - Design wind speed factors (ground roughness, building
size and height above ground)
S3 - Design wind speed factors (statistical factor)
SD1 - Design spectral response at a 1.0 second period
SDS - Design spectral acceleration in the short period range
∫dEh - Hysteretic energy absorbed by the element during the
response history
T - Fundamental period of the structure
T1 - Fundamental period
u - The relative displacement
u& - Velocities
u&& - Acceleration with respect to the ground
gzgygx uuu &&&&&& ,, - Component of uniform ground acceleration
V - Basic wind speed
V - Design base shear
Vs - Design wind speed
W - Seismic dead load
ω - Circular frequency
ϖ - Frequency of earthquake excitation
wi - The seismic weight assigned in Level i
wx, wi - Portion of w located at level x and i respectively
xxviii
x - Distance from the base to the centroid of the section
ξ - Damping ratio
Z - Seismic zone factor
eZ - Section modulus in in3
xxix
LIST OF APPENDICES
APPENDIX TITLE
A Example: Earthquake Static Equivalent Analysis
B Example: Design Capacity Calculation (BS 8110)
C Example: Input data for Nonlinear-Analysis used
IDARC-2D
D Example: Output data for Nonlinear-Analysis
used IDARC-2D
CHAPTER 1
INTRODUCTION
1.1 General
Public building structures in Malaysia which include offices, apartment and
hospitals are heavily developed in many states. This corresponds to the needs of quality
life and increasing population. The public buildings in Malaysia are usually categorised
as reinforced concrete buildings. These buildings are designed to resist gravity loads,
wind loads and notional horizontal loads in accordance with the British code BS 8110,
which does not have any special provision for seismic loads. However due to far-field
effects of earthquake in Sumatra, these buildings are occasionally subjected to tremors.
In year of 2004 and 2005, repeated tremors from the Sumatran earthquakes had
brought concerns to the public, government authorities, engineers and researchers on
safety especially when no earthquake design practice had been taken into consideration
for our buildings. As part of the responsibility to the public, this study concerns the
safety aspect of public buildings due to seismic effects.
On 26 December 2004, the most powerful earthquake in 40 years triggered
massive tidal waves that slammed into coastline across Asia which killed almost
100,000 people in the affected country. The havoc that happened in the aftermath of this
2
wave should be taken as an early sign and lessons for the respective authority. The
tsunami hit Penang, Kedah and Perlis and caused major damages and loss of lives. The
8.9 magnitude earthquake centered off the west coast of the Indonesian Island of
Sumatra had caused tremors in Klang Valley, Selangor and other parts of the East Cost
like Terengganu and Kelantan. Hundreds of civilians and patients were evacuated from
hospitals, police stations, hotels, and apartments, until the vibrations that lasted for more
than five minutes stopped.
This is only one of the scenarios that we have experienced at the end of year
2004 as reported in the media. Eventually many earthquake events from Sumatra’s
earthquakes since 1998 to 2007 have been reported repeatedly. The assumptions saying
that Malaysia is free from earthquake an effect has changed since most of the tremors
are felt, especially at medium and high-rise buildings. Thus the structure’s safety and
adequacy in resisting earthquake effects have been questioned. Detailed inspection and
research should be conducted in the future to determine the exact performance of the
building before and after each earthquake.
1.2 Objective
The objectives of the research are:
1). To identify the design base shear force for buildings in Malaysia by
performing wind and earthquake static equivalent analyses.
2). To identify the design capacity level of buildings and the maximum
allowable lateral load based on shear coefficients of wind and earthquake
loadings by performing earthquake linear static and dynamic analyses.
3). To specify the damage level of buildings by performing earthquake non-
linear dynamic analysis
3
Considerations on seismic effect on structural building design have not been
practiced in Malaysia, because there are currently no design guidelines for seismic loads.
Even though the development of the design guideline is on going, it may take time to
publish. Therefore this study contributes to the development process for seismic loads
especially for the reinforced concrete buildings.
1.3 Scope of Work
The scope of research covers some aspects mentioned below:
1). Seven public buildings were chosen from different locations in the
Peninsular and East Malaysia which were categorized as medium-rise and
high-rise buildings. All buildings are reinforced concrete moment
resisting frame type. These buildings were chosen based on the typical
existing building in Malaysia, varies of location, occupancy and varies of
height level.
2). Finite Element Modeling was used in structural analysis, which consist of
liner and non-linear analysis. The computer software, SAP 2000 was
used in static and dynamic linear analysis, while IDARC 2D was used in
dynamic non-linear analysis.
3). Various earthquake ground accelerations (0.05g, 0.10g, 0.15g, and 0.20g)
were used in earthquake Static Equivalent, Response Spectrum and Time
History Analysis. The ground motions were scaled to 5% damped
spectral acceleration at the fundamental frequency of the structure.
Therefore various wind velocities (20m/s, 30m/s, 40m/s, 50m/s) were
used in the Wind Static Analysis.
4
4). UBC-97 and CP3:1972 were used as the design codes in determining the
lateral load from earthquake and wind respectively. In order to identify
the design capacity in each element of reinforced concrete building
frames, the BS 8110 design code was referred.
1.4 Research Methodology
The steps for a comparative study of earthquake and wind loads on the
performance of reinforced concrete buildings in Malaysia are shown in Figure 1.1. The
chronological steps taken in the study are described below.
Step 1: Literature, Collecting Data and Design Specifications for Reinforced Concrete
Buildings
The collection of related information on potential seismic risks in the region as
well as the related research work done by others researchers was emphasized in this
stage. Background studies of existing buildings in Malaysia that did not consider seismic
effects were reviewed. The current practice of wind design in Malaysia was reviewed.
Selected building data for modeling analysis were collected from the government
authorities. Then, design specifications for each building were identified.
Step 2: Technique for Finite Element Modeling and Analysis Design
To study the performance of buildings, Finite Element Modeling was used in
structural analyses, which consist of linear and non-linear analysis. The computer
software, SAP 2000 was used in static and dynamic linear analysis, while IDARC 2D
was used in dynamic non-linear analysis. Under the static equivalent linear analysis,
buildings performances under wind and earthquake load were compared. Dynamic
5
analysis (e.g. free vibration analysis, time history analysis and response spectrum
analysis) were used for further study of seismic load effects.
Step 3: Performance of Reinforced Concrete Buildings
The response obtained from static wind analyses, and both static and dynamic
seismic analyses which were conducted in previous step were used for subsequent
comparison. Thus, the governing parameter (wind or earthquake) were determined. In
addition, the responses of buildings were evaluated to check whether the component
forces and deformation meet the criteria requirements. Other parameters such as base
shear and moment base capacities of buildings were compared to identify the optimum
acceleration levels that can cause failures to the building structures under the various
intensities of earthquake. Therefore to evaluate the expected damage, appropriate
structural response parameters such as inter-storey drift, and damage index were used.
Step 4: Discussion and Conclusion
The final step presented the summary and conclusion of the whole study, which
includes discussion and recommendations of the study to improve the research.
1.5 Organisation of Thesis
The thesis is divided into six chapters, as shown in Figure 1.1. Chapter 1 outlines
the general introduction, objective of the study, scope of work and the methodology
used. Detail literature reviews are presented in Chapter 2. In this chapter current
Malaysia practice of wind and seismic design and potential of seismic activities in
Malaysia are discussed. The performances of the reinforced concrete buildings from
previous studies are also discussed. Chapter 3 outlines the theoretical background which
includes the static linear analysis for wind and earthquake. Besides further analysis in
6
earthquake dynamic linear and non-linear is also emphasized in this chapter. The
modeling techniques applied for finite element analysis are shown in Chapter 4. This
chapter also highlights the earthquake dynamic analysis method which includes free
vibration, response spectrum and time history analysis. Chapter 5 presents the results of
modeled analyses in terms of the performance of reinforced concrete buildings. This
includes dynamic response of structure, maximum stress, maximum response and
damage analysis. Chapter 6 summarizes the findings of this study and the conclusions
from this research. Recommendations are listed in this chapter to improve the research
for the betterment of the next generation.
7
CH
APT
ER
1
In
trodu
ctio
n, o
bjec
tive,
scop
e an
d m
etho
dolo
gy
CH
APT
ER
2
Li
tera
ture
revi
ew o
f win
d an
d ea
rthqu
ake
in M
alay
sia,
re
info
rced
con
cret
e bu
ildin
gs
base
d on
per
form
ance
CH
APT
ER
3
Th
eore
tical
bac
kgro
und
of d
esig
n an
d an
alys
is o
f win
d an
d ea
rthqu
ake
stud
y
CH
APT
ER
5
R
esul
ts &
Dis
cuss
ions
Line
ar A
naly
sis:
Mod
al
resp
onse
, bas
e sh
ear,
disp
lace
men
t, in
ter-
stor
ey d
rift,
max
. for
ces
& m
omen
t
Non
-line
ar A
naly
sis:
M
odal
resp
onse
, int
er-
stor
ey d
rift,
dam
age
patte
rn, d
amag
e in
dex,
vu
lner
abili
ty fr
ame.
CH
APT
ER
6
Su
mm
ary,
co
nclu
sion
and
re
com
men
datio
ns
CH
APT
ER
4
M
odel
ing
tech
niqu
e in
FE
M fo
r sta
tic li
near
an
alys
is, d
ynam
ic li
near
an
alys
is; R
SA, a
nd
dyna
mic
non
-line
ar
anal
ysis
; TH
A
STE
P 4
C
oncl
usio
n
STE
P 1
Li
tera
ture
, Col
lect
ing
Dat
a an
d D
esig
n Sp
ecifi
catio
n fo
r R
einf
orce
d C
oncr
ete
Bui
ldin
gs
STE
P 2
M
odel
ing
Tech
niqu
e fo
r Fin
ite E
lem
ent
Mod
elin
g an
d A
naly
sis D
esig
n
STE
P 3
Pe
rfor
man
ce o
f R
einf
orce
d C
oncr
ete
Bui
ldin
gs
Figu
re 1
. 1: M
etho
dolo
gy a
nd o
rgan
isat
ion
of th
e th
esis
