STRUCTURAL SYSTEM ANALYSIS AND DESIGN FOR

SAFE HOUSE

Mohammad Rezaeianpakizeh

A project report submitted in partial fulfillment of the

Requirements for the award of the degree of

Master of Engineering (Civil-Structure)

Faculty of Civil Engineering

Universiti Teknologi Malaysia

JULY 2012

iii

Dedicated to my beloved mother and devoted father.

Words cannot describe how much they mean to me.

iv

ACKNOWLEDGEMENT

The realization of this research was only possible due to the several people's

collaboration, to which desire to express my gratefulness.

I would like to thank in a special way to Assoc. Prof. Dr. Abdul Kadir

Marsono, my supervisor, I am grateful for the trust deposited in my work and for the

motivation demonstrated along this research. His support was without a doubt crucial

in my dedication this investigation. He has been the ideal thesis supervisor. Without

his inspirational instruction and guidance I was not able to complete this project. His

sage advice, insightful criticisms, and patient encouragement aided the writing of this

thesis in innumerable ways.

Appreciation is extended to all laboratory staff for advices and suggestions of

the work, and for the friendship that always demonstrated along these months of this

project.

I would also like to express my gratitude to all my friends especially,

Hamidreza Khoshnoud for his extended support. With his help, it was possible for

me to complete this project.

v

ABSTRACT

The observation of post-earthquakes damages on reinforced concrete buildings has

clearly shown that the presence of nonstructural elements, such as infill walls, may

significantly affect the seismic performance of buildings. The study describes the

analysis and design, the engineering process the new type of safe room according to

the FEMA guidance. It also evaluates the effects of in-fill frames and the linear

response of reinforced concrete braced frames and comparison with frames with

shear wall. The main conclusion drawn from this study is to elaborate that the

masonry in-fills, are strongly influence the structural seismic response and contribute

to the overall stiffness and can decrease drifts and displacements. Infill walls have

significant role in the strength and ductility of RC framed structures and should be

considered in both analysis and design globally. These walls make the structure

significantly stiffer, and reduce the natural period of the structure. Locally, infill

walls changed the load path, the distribution of forces between different elements of

the structure, and the demand forces on their adjacent elements of the bounding

frame. Due to the high relative stiffness of the infill frames, they act as the main

lateral load-resisting system and attract larger portions of the earthquake-induced

inertia forces.

vi

ABSTRACT

Pemerhatian selepas gempa bumi yang menaberi kerosakan ke atas bangunan

konkrit bertetulang telah jelas menunjukkan bahawa kehadiran unsur bukan struktur

seperti dinding pengisian, boleh memberi kesan kepada prestasi seismik bangunan.

Kajian ini menerangkan analisis dan reka bentuk, proses kejuruteraan jenis baru

“safe room” mengikut kepada petunjuk FEMA dan menilai kesan kerongka pengisi

dan tindak balas linear kerangka berembat konkrit bertetulang dan dengan kerangka

dinding ricih. Kesimpulan utama yang diperolehi daripada kajian ini adalah untuk

menjelaskan bahawa bato dalam-mengisi. Kuat mempengaruhi tindak balas seismik

struktur dan menyumbang kepada kekukuhan keseluruhan dan boleh mengurangkan

sesaran dan anjakan. Dinding pengisian mempunyai peranan penting dalam kekuatan

dan kemuluran struktur kerangka RC dan perlu dipertimbangkan dalam analisis dan

reka bentuk global. Dinding ini membuat struktur ketara yang lebih kuat,

mengurangkan tempoh gegaran semulajadi struktur. Dinding pengisian mengubah

laluan beban, dan mengagihkan daya di antara elemen-elemen struktur yang berbeza,

dan berkuasa memindahkan beban ke bersebelahan. Disebabkan oleh kekukuhan

tinggi berbanding dengan kerang ka pengisian, mereka bertindak sebagai sistem sisi

utama menentang beban dan menarik bahagian yang lebih besar daya inersia.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

TITLE vi

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

LIST OF CONTENT vii

LIST OF TABLE x

LIST OF FIGURES xi

LIST OF SYMBOLS xiii

CHAPTER 1 INTRODUCTION

1.1 Introduction .................................................................. 1

1.2 problem statement ....................................................... 2

1.3 Objective of study ........................................................ 3

1.4 Scope of study .............................................................. 4

1.5 Significant of study ...................................................... 5

CHAPTER 2 Literature review

2.1 FEMA 320.................................................................... 7

2.2 FEMA 361.................................................................... 8

2.3 FEMA 431.................................................................... 9

2.4 Characteristics of Tornadoes ....................................... 10

2.5.Shear Wall ................................................................... 11

2.6 Bracing ........................................................................ 12

2.61 Concrete Brace .......................................................... 13

2.7 Effect of infill walls on reinforced concrete frame ..... 15

viii

2.8 Behavior of infilled frames ......................................... 21

2.9 Reinforced Concrete Frames with Masonry Infill ...... 24

2.10 Seismic Behaviour of RC Frames

with masonry wall ..................................................... 25

CHAPTER 3 METHODOLOGY

3.1 Introduction .................................................................. 30

3.2 ETABS Software.......................................................... 36

3.3 Load Combinations Using

Allowable Stress Design .............................................. 37

3.4 Tornado Community Safe Room

Design Criteria ............................................................. 38

3.5 Wind Design Parameters for Tornado

Community Safe Rooms .............................................. 39

3.5.1 Wind Pressure (Y- Direction) ............................. 41

3.5.2 Wind Pressure (X- Direction) ............................. 42

3.6 Seismic analysis ........................................................... 43

3.7 Static analysis ............................................................... 43

3.7.1 Storey1 (I-S model) ............................................. 44

3.7.2 Storey2 ................................................................ 45

3.7.3 Storey3 ................................................................ 45

3.7.4 Steel elements ..................................................... 46

3.7.5 Concrete element................................................. 46

3.7.6 Concrete Beam ................................................... 47

3.8 Response spectrum ....................................................... 48

3.9 Time History ................................................................ 50

3.9.1 ELCENTRO Earthquake ........................................... 50

CHAPTER 4 Findings and Results

4.1 Finding and Results ...................................................... 53

4.2 Models I-S and B-S ...................................................... 57

ix

4.3 Model I-B and B-B ...................................................... 59

4.4 Models B-S and B-B .................................................... 60

CHAPTER 5 Discussion of Result ........................................................... 62

CHAPTER 6 Conclusion and Recommendation..................................... 63

REFERENCES ................................................................................................... 65

APPENDIX ......................................................................................................... 70

x

LIST OF TABLES

TABLE TITLE PAGE

4.1 Base shear and weight of the models 53

4.2 Maximum Displacements 54

4.3 Maximum Drifts 55

xi

LIST OF FIGUERS

FIGURE TITLE PAGE

1.1 Plane Of Building with Safe House 4

1.3 Safe House With Shear Wall 5

1.3 Example of Failure 6

2.1 Desai simple triangular modelling in different loading

stages

14

3.1 Models of study 31

3.2 I-S Model 32

3.3 B-S Model 33

3.4 I-B Model 33

3.5 B-B Model 34

3.6 Flow chart of this research 35

3.7 Tornado Safe Room Design Wind Map 39

3.8 GPF Y-Direction 41

3.9 GPF Y-Directions 42

3.10 Response Spectrum Record 48

3.11 ELCENTRO Acceleration 51

3.12 ELCENTRO Record 51

xii

3.13 Scaled ELCENTRO Record 52

4.1 CM Drift in Bare frame with shear wall 56

4.2 CM Drift in in-fill frame with shear wall 56

4.3 CM Drift in Bare frame with Brace 56

4.4 CM Drift in In-fill frame with Brace 57

4.5 Maximum story drift in I-S and B-S models 57

4.6 Maximum story displacements in I-S and B-S models. 58

4.7 Maximum acceleration of each story in I-S and B-S

models

58

4.8 Maximum story drift in I-B and B-B models. 59

4.9 Maximum story displacements in I-S and B-S models 59

4.10 Maximum acceleration of each story in I-S and B-S

models.

60

4.11 Maximum story drift in B-S and B-S models. 60

4.12 Maximum story displacements in B-B and B-S models 61

4.13 Maximum acceleration of each story in B-B and B-S

models

61

xiii

TABLE OF SYMBOLS

G = gust effect factor for MWFRSs of flexible buildings and other structures

GCp,, = combined net pressure coefficient for a parapet

GCp =product of external pressure coefficient and gusteffect factor to be used in

determination of wind loads for buildings

GCpj = product of the equivalent external pressure coefficient and gust-effect factor

to be used in determination of wind loads for MWFRS of low-ris buildings

GCpi = product of internal pressure coefficient and gusteffect factor to be used in

determination of wind loads for buildings

q = velocity pressure, in lb/ft2 (IV/m2)

qj, = velocity pressure evaluated at height z = h, in lb/ft2 (IV/m2)

q; = velocity pressure for internal pressure determination, in lb/ft2 (IV/m2)

qp =velocity pressure at top of parapet, in lb/ft2 (IV/m2)

q, =velocity pressure evaluated at height z above ground, in lb/ft2 (IV/m2)

R = resonant response factor

Ss = mapped MCE, 5 percent damped, spectral response acceleration parameter at

short periods

xiv

S1 = mapped MCE, 5 percent damped, spectral response acceleration parameter at a

period of 1 s

SaM = the site-specific MCE spectral response acceleration at any period

SDs = design, 5 percent damped, spectral response acceleration parameter at short

periods

SMs = the MCE, 5 percent damped, spectral response acceleration at short periods

adjusted

for site class effects

SMl = the MCE, 5 percent damped, spectral response acceleration at a period of 1 s

adjusted for site class effects

T = the fundamental period of the building

T, = approximate fundamental period of the building

TL = long-period transition period

1

CHAPTER 1

INTRODUCTION

1.1 Introduction

Buildings in any geographic location are subject to a wide variety of natural

phenomena such as windstorms, floods, earthquakes, and other hazards. While the

occurrence of these incidents cannot be precisely predicted, their impacts are well

understood and may be can able to be managed effectively through a comprehensive

program of hazard mitigation planning.

Every year earthquakes, tornadoes and other extreme windstorm cause

fatalities or even kill people, devastate and millions of dollars’ worth property.

The likelihood that a tornado will strike building is a matter of probability. Tornado

damage to building is predictable at certain accuracy. Administrator of school and

other public buildings should have a risk analysis performed to determine the

likelihood that a natural disaster will occur and look at the potential severity of the

event. If a building determined to be at risk, the safest part of the building may offer

the protection if a natural disaster strikes. From the local perspectives a tornado is

the most destructive of all atmospheric phenomena. The wind speed generated by

some tornadoes is so great such that designing for these extreme winds is

unaffordable and beyond the scope of building codes and engineering standard.

Most buildings that have received engineering attention, such as schools, and

that are built in accordance with sound construction practices can usually withstand

wind speeds but may provide sufficient resistance to tornadic wind only if the

2

building is located on the outer edge of the tornado vortex. In addition if a portion of

the building is built to a higher tornado design standard, then both building and

occupant survival ability are improved.

It is an important measure for the international society establishing the

emergency shelter to deal with the emergent events and victims. And also, the

emergency shelter is the temporary living place for people in modern big cities to

avoid the danger of natural disasters, such as the earthquake, fire, explosion, flood,

and so on. Based on scientific planning and standard management, the emergency

shelter could be used to supply the basic subsistence requirements for people in

dangers. Actually, the planning construction of the emergency shelter in cities is a

kind of systems project, which included all kinds of inspects in society.

Shear walls, and braced frames, have been an effective and valuable method

to enhance structures against lateral loads. In wind or seismic excitations, inclined

elements react as truss web elements which would bear compression or tension

stresses.

1.2 Problem statement

When the extreme hazard events occur almost every things will be destroy

and cause devastation and fatalities. The structure will be damaged from various

aspects of structural engineering. Well-constructed houses destroy and some

structure lift from foundation, roofs and some walls torn from structure and extensive

damage will be to non-structural elements such as, windows, doors and some curtain

walls. Some buildings have shelter or small safe-room, but there are not available or

accessible during event. The orders to study the effects of natural disaster, the nature

of extreme earthquake and flood have to be understood in structural engineering

point of view.

The observation of post-earthquakes damages on reinforced concrete

buildings has clearly shown that the presence of nonstructural elements, such as infill

3

walls, may significantly affect the seismic performance of buildings, both in terms of

seismic demand and capacity. The experience developed about the seismic

assessment of existing buildings has definitely demonstrated that infill masonry walls

often behave like real primary elements, and anyway have a significant role in the

structural response recently, the influence of infill walls on the seismic structural

response of RC buildings has been widely investigated by many research

experimental and numerical studies.

Low tensile strength of concrete material and moulding made it a challenge to

use in inclined members. In practice, there have been various methods to consider

this defect such as disengagement of brace elements in tension or utilization of pre-

stressed braces.

1.3 Objectives of study

The specific objectives of this study are as follows:

- To describe in the form of analysis and design, the engineering process of

the new type of shelter or safe room embedded inside the main building.

- To evaluate of linear response of reinforced concrete frames, braced frames

and comparison with frames with shear wall.

- To investigate the stiffness of infills in frames of building and evaluate the

interstory drift for lateral loads.

4

1.4 Scope of study

The purpose of this research is to study the linear response of the new type of

shelter or safe room that surrounded by reinforced concrete frames which contain

reinforced concrete braces or shear wall as the major structural elements against

lateral loads.

This study focuses on evaluation of displacement and inter-story drift of

reinforced concrete braced frames for earthquake and compare with frames with

shear wall in two cases, infill frame and non-infill frame.

Figure 1.1 Plan of building with safe house

5

Figure 1.2 Perspective view of safe house by shear wall

1.5 Significant of study

A reliable assessment of the seismic response of existing RC framed

buildings should include an accurate model of the infill panels. In this research, the

numerical analysis is carried out to evaluate the effect of stiffness of the infill walls

on the behavior of structures subjected to lateral loads. It is observed that the

presence of correctly distributed infill elements can mitigate horizontal

displacements and increase the overall resistance to horizontal actions. In general, a

significant increase in the stiffness of the system could be induced, with a consequent

decrease of the natural vibration periods of the building.

6

Figure 1.3 (a) typical column failure in the first story. Infill wall contributed

to lateral stiffness and short column effects around windows. (b), (c): soft

storey mechanism at the first level in a RC building

82

6.1 REFERENCES

1. Desai JP, Jain AK, Arya AS, Seismic response of R.C. braced frames, Computers

and Structures, No. 4, 29[1988]557-68.

2. Iskhakov I, Self-Variable Stiffness System for Optimal Seismic Response of RC

Frame with Concrete Braces, Earthquake Resistant Engineering Structures

III, [2001]

3. Xu S, Niu D, Seismic behavior of reinforced concrete braced frame, ACI

Structural Journal, No. 1, 100(2003)120-25.

4. Watanabe, Development of the "Self-Installing PCa Brace Method" for Seismic

Reinforcement of Building Walls, October 2002.

5. Khaloo∗ and M. Mahdi Mohseni, NONLINEAR SEISMIC BEHAVIOR OF RC

FRAMES WITH RC BRACES.A.R. Department of Civil Engineering, Sharif

University of Technology, Azadi Avenue P.O. Box: 11365-9313, Tehran,

Iran [2004]

6. Bayındırlık ve _skan Bakanlıgı, “Afet Bölgelerinde Yapılacak Yapılar Hakkında

Yönetmelik” (ABYYHY-98), Türkiye Hazır Beton Birligi, [1999].

7. Sucuoglu, H. and McNiven, H. D. “Seismic Shear Capacity of Reinforced

Masonry Piers”, Journal of Structural Engineering, Vol. 117, No. 7, pp. 2166-

2187, July [1991].

8. Sucuoglu, H. and Erberik, A., “Performance Evaluation of a Three-Storey

Unreinforced Masonry Building During the 1992 Erzincan Earthquake,

Earthquake Engineering and Structural Dynamics, Vol. 26, [1997].

9. Paulay, T. and Priestley, M. J. N, Seismic Design of Reinforced Concrete and

Masonry Buildings”, John Wiley & Sons, Inc, [1992].

10. Smith, B. S. and Coull, A., “Tall Building Structures: Analysis and Design”, John

Wiley & Sons, Inc., [1991].

83

11. Smith, B.S. and Carter, C., “A Method of Analysis for Infilled Frames”,Proc.

ICE, Vol. 44, pp.31-48, September [1969].

12. Applied Technology Council, “NEHRP Guidelines for the Seismic Rehabilitation

of Buildings” (ATC 33), Federal Emergency Management Agency Report

FEMA 273, Washington [1997].

13. Roko Zarinic, Design Loads for Building, Turkish Standards Institute, Ankara,

November [1997].

14. Gülkan, P. and Sözen, M.A., “Procedure for Determining Seismic Vulnerability

of Building Structures”, ACI Structural Journal, Vol. 96, No.3, pp. 336-342,

[1999].

15. Ersoy, U. and Marjani, F., “ Behavior of Brick Infilled Reinforced Concrete

Frames Under Reversed Cyclic Loading”, ECAS 2002 Internatiol

Symposium on Structural and Earthquake Engineering Symposium

Proceedings, pp. 142-150, October [2002].

16. Demir, F. and Sivri, M., “Earthquake Response of Masonry Infılled, July 2003

17. Pujol S, Fick D. The test of a full-scale three-story RC structure with masonry

infill walls, Engineering Structures 32[2010].

18. Mónica Puglisi, Maylett Uzcategui, Modeling of masonry of infilled frames, Part

I: The plastic concentrator, Engineering Structures 31[2009]113-8.