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SELECTION OF STRUCTURAL SYSTEMS AND MATERIALS:
MINIMIZING LATERAL DRIFT AND COST OF TALL BUILDINGS
IN SAUDI ARABIA
by
Othman Subhi AlShamrani
A Thesis Presented to the FACULTY OF THE SCHOOL OF
ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA In Partial of Fulfillment of
the Requirements for the Degree
MASTER OF BUILDING SCIENCE
May 2007
Copyright 2007 Othman Subhi AlShamrani
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Acknowledgments
First of all, I am very grateful to God who granted me with a
lot of help and support to
achieve my goal and gave me the opportunity to complete my
higher education in the
United States, without him I wouldve not been able to do it.
Second, I thank my parents,
Subhi Daifullah and Rahmah Mohammed, for their great support and
encouragement
throughout my education. They have been providing me with all
the needs and cared
more than what I expected. I thank them for their best advices,
concerns, and their
prayers for me.
I would like to express special gratitude to my advisor and
committee chair professor G
Goetz Schierle. Professor Schierle provided me with guidance and
advices that enabled
me to achieve my degree. His efforts, suggestions, and prompt
respond are the reasons
that ease to maintain the standard of scholarship that this
thesis required. I would as well
thank him for his valuable book which was the one of the most
useful source for my
thesis.
I would like to thank my committee members: Professor Doug
Noble, the associate dean
who gave me a lot from his precious time and guided me to narrow
dawn my thesis. I
really appreciate his effort and instructions. He taught me to
manage my work with the
time. I really thank the expert person Mr. Dimitry Vergun for
his advices and abundant
information that helped me to accommodate my test with the real
works in the consulting
offices. Also, I am grateful to Professor Thomas Spiegelhalter
for his guidance,
encouragements, and his valuable advices about some books. I
would also like to thank
Dr. Mohammed AlSatari for providing me with very useful
information in the field of
civil and structural engineering. I really appreciate his
efforts, guidance, tolerance and
patience. I would also like to give special acknowledgement for
Professor Marc Schiler
the Director of Master of Building Science Program. Professor
Schiler taught me a lot,
encouraged me to publish paper, and revised my thesis.
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I am grateful to the Government of Saudi Arabia as well as King
Faisal University for
providing me with all the financial needs that kept me worry
free during my studies.
Many individuals have provided support, advices, and
encouragement to me in the
completion of this dissertation. I am grateful to Dr. Rashed
Alshaali for assisting me to
stable my life in Los Angels as well as giving me valuable
advices to accomplish my aim
easily. I would like to thank my friend, Merzak Toubal, for his
assistance with ideas. I
would also like to express gratitude to my undergraduate
Instructor Dr. Turki ALQahtani
for his advices and guidance to join the University of Southern
California to earn my
master degree. I would also like to thank my undergraduate
professors, Mohammed
ALNuman, Abdullah Albashir, Ahmed Almusallami, Khaled AlMaddlah,
Mansor
AlJadid, Ibrahim Almofeez, Hashim AlSaleh, Ahmed Alrwashid,
Faris Alfaraidhy,
AbdulAziz AlHamad, Ali AlQarni, AbdulAziz AlGhonaimi, Mahammed
Imttar, and
Mohammed Foad for their tolerance, patience and care. I also
thank my friend Engineer
Montasir ALMasaud for helping me to apply to the American
Universities. I would also
thank his brother Dr. Mohammed AlMasaud the Dean of the College
of Architecture in
King Faisal University for approving my scholarship. I will not
forget to thank Dr. Saeed
AlOmar for his valuable advices and guidance.
Special thanks to my relatives, Hawash Daifullah, Ali Subhi,
Saeed Subhi, Hailmah
Subhi, AbdulKareem Subhi, Ishah Subhi, Khadijah Subhi, Moaad
Subhi, Mosa Subhi,
Mohammed Daifullah, Talal Hamdan, Ali Daifullah, Saeed
Daifullah, Amer Ali, Ahmed
Hawash, Mohammed Ali, Tareq Mohammed, Abdulraheem Ali,
Abdulrhman Abdullah,
and Ibrahim Mohammed for their concerns and questions.
Finally, many warm thanks for her and just for her, my wife the
mother of my precious
sons Sultan and Salman for her daily care and concern. Mona
Masfer AlShamrani the one
who encouraged and assisted me to achieve my goals. I really
appreciate her concern,
struggle, tolerance, patience, and love.
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TABLE OF CONTENTS Acknowledgments...ii List of Tables.......ix
List of Figures.... xiv
Abstract...........................................................................................................................xxii
Chapter 1. Introduction
1.1. Introduction 1 1.2. Objective and Scope of Study 1 1.3.
Selection Steps 1 1.4. Structural Systems and Materials 2 1.5.
Selection of Structural Systems.. 4 1.6. Selection Criteria 5 1.7.
Tall Buildings in Saudi Arabia. 5 1.8. Wind Load Considerations...
7
Chapter 2. Research Methodology 2.1. Introduction. 8 2.2. Data
Collection Methods 8 2.3. Thesis Tools and Testing Model. 8 2.3.1.
Testing Model. 8 2.3.2. STAAD Pro 2005 Software 9 2.4. Design
Methods.. 10 2.5. Data Analysis Method.12 2.5.1. Selection of
Structural System Method.. 12 2.5.2. Drift Measuring Method. 13
Chapter 3. Selection of Structural System Criteria 3.1.
Introduction. 15 3.2. Proposed General Criteria List 16 3.3. Case
Study Selection Process... 18 3.4. Structural Criteria. 19 3.4.1.
Material Cost 19 3.4.2. Labor Cost 19 3.4.3. Integration and
Synergy 20 3.4.4. Ease of Construction 20 3.4.5. Span Limits.. 21
3.4.6. Gravity Load 24 3.4.7. Seismic Load 25 3.4.8. Noise Control
27
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3.4.9. Fire Safety 28 3.4.10. Sustainability (durability and
recyclable). 28 3.4.11. Strength, Stiffness, Stability, and Synergy
29 3.4.12. Corrosion and Moisture Resistance.. 30 3.4.13. Material
Transportation 30 3.4.14. Environmental Impact and Energy
Consumption... 31 3.4.15. Low Maintenance Cost 32 3.4.16. Design
Possibility... 32 3.4.17. Material Availability... 33 3.4.18.
Building Type. 34 3.4.19. Building Location.. 34 3.4.20. Building
Height Limit 34 3.4.21. Code Requirements 35 3.4.22. Site
Conditions (Access and Storage) 36 3.4.23. Technology Availability.
36 3.4.24. Energy Efficiency and Thermal Mass 37 3.4.25. Soil Class
38 3.4.26. Healthy Living & Indoor Air Quality. 39 3.4.27.
Morphology 39 3.4.28. Weather and Climate Condition. 40 3.4.29.
Security.. 40 3.4.30. Exterior Cladding... 41 3.4.31. Minimal Story
Height. 41 3.4.32. Cash Flow and Financing Costs. 42 3.4.33.
Building Configuration... 42 3.4.34. Future Modification 42
Chapter 4. Background
4.1. Introduction. 43 4.2. Wind Force.. 43 4.2.1. Wind
Situations... 44 4.2.2. Correlation of Wind Speed and Pressure. 44
4.2.3. General Wind Effects. 44 4.2.3.1. Direct Positive Pressure..
45 4.2.3.2. Aerodynamic Drag. 45 4.2.3.3. Negative Pressure
(Suction)... 45 4.2.3.4. Rocking Effects.. 46 4.2.3.5. Harmonic
Effects... 46 4.2.3.6. Clean Off Effect. 46 4.2.4. Critical Wind
Effects on Buildings. 47 4.2.4.1. Inward Pressure on Exterior
Wall... 47 4.2.4.2. Overturn Effect... 48 4.2.4.3. Shear Force 48
4.2.4.4. Pressure on Roof Surfaces.. 48 4.2.4.5. Torsional Effect..
49
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4.2.4.6. Dynamic Effects. 49 4.2.5. Code Requirements for Wind.
49 4.2.5.1. Basic Wind Speed in Saudi Arabia. 50 4.2.5.2. Design
Wind... 51 4.2.5.3. Wind Pressure Calculation Example.. 54 4.2.6.
Special Requirements 55 4.2.6.1 Overturning Moment. 55 4.2.6.2.
Torsion.. 55 4.3. Lateral Drift... 55 4.3.1. Drift Definition. 55
4.3.2. Code Requirements for Drift. 57 4.3.3. Drift Effect 57
4.3.3.1. Height to Width Ratios.. 58 4.3.3.2. Span of Girders.. 58
4.3.3.3. Member Size of Frame..58 4.4. Lateral Force Resistance
Structural Systems........................................... 59
4.4.1. Moment
Frame..........................................................................................59
4.4.1.2. Lateral Drift of Moment
Frame...............................................................
61 4.4.2. Braced Frame 62 4.4.2.2. Lateral Drift of Braced
Frame..................................................................
63 4.4.3. Shear Walls64 4.4.3.2. Lateral Drift of Shear
Wall.......................................................................
67 4.5. Structural Systems Comparisons... 68 4.6. Allowable Stress
Design 69 4.6.1. Allowable Stress Definition... 69 4.6.2. Allowable
Stresses for Different Materials 70 4.6.2.1. Allowable Stresses for
Wood 70 4.6.2.2. Allowable Stresses for Steel.. 70 4.6.2.3.
Allowable Stresses for Masonry 71 4.6.2.4. Allowable Stresses for
Concrete 71 4.6.3. Steel Buckling... 72 4.6.4. Slenderness Ratio..
73 4.7. Previous Studies (Lateral Drift Caused by Wind Forces)..
74
Chapter 5. Data Analysis 5.1. Introduction. 76 5.2. Simulation
Assumptions. 76 5.2.1. Lateral Loads.. 76 5.2.2. Allowable Stresses
77 5.2.3. Framing Schemes 77 5.2.4. Cost Estimate.. 77 5.2.4.1.
Steel Cost 77 5.2.4.2. Concrete Cost... 78 5.3. 10 Story Building.
78
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5.3.1. Loads for 10 Story Building 78 5.3.2. Combined Axial +
Bending Stress for 10 Story Building... 81 5.3.3. Member Sizes for
a 10 Story Building 82 5.3.3.1. 10 Story Steel Moment Frame. 82
5.3.3.2. 10 Story Concrete Moment Frame... 83 5.3.3.3. 10 Story
Steel Braced Frame... 84 5.3.3.4. 10 Story Concrete Shear Wall. 85
5.3.4. Cost for a 10 Story Building 86 5.4. 20 Story Building. 87
5.4.1. Load for 20 Story Building.. 87 5.4.2. Combined Stress for
20 Story Building... 88 5.4.3. Member Sizes for a 20 Story Building
89 5.4.3.1. 20 Story Steel Moment Frame. 89 5.4.3.2. 20 Story
Concrete Moment Frame... 90 5.4.3.3. 20 Story Steel Braced Frame...
91 5.4.3.4. 20 Story Concrete Shear Wall.. 92 5.4.4. Cost for a 20
Story Building 93 5.5. 30 Story Building. 94 5.5.1. Load of 30
Story Building... 94 5.5.2. Combined Stresses for a 30 Story
Building. 95 5.5.3. Member Sizes for a 30 Story Building 96
5.5.3.1. 30 Story Steel Moment Frame. 96 5.5.3.2. 30 Story Concrete
Moment Frame... 97 5.5.3.3. 30 Story Steel Braced Frame... 98
5.5.3.4. 30 Story Concrete Shear Wall.. 99 5.5.4. Cost of 30 Story
Building 100 5.6. 40 Story Building. 101 5.6.1. Load for 40 Story
Building.. 102 5.6.2. Combined Stresses for a 40 Story Building.
102 5.6.3. Member Sizes for a 40 story Building. 103 5.6.3.1. 40
Story Steel Moment Frame. 103 5.6.3.2. 40 Story Concrete Moment
Frame... 104 5.6.3.3. 40 Story Steel Braced Frame... 105 5.6.3.4.
40 Story Concrete Shear Wall.. 107 5.6.4. Cost for 40 Story
Building... 108 5.6.5. Total Cost Comparisons... 109
Chapter 6. Simulations Results 6.1. Introduction. 110
6.2. Lateral Drift 110 6.2.1. Lateral Drift of 10 Story
Building.. 110 6.2.2. Lateral Drift of 20 Story Building.. 113
6.2.3. Lateral Drift of 30 Story Building.. 116 6.2.4. Lateral
Drift of 40 Story Building.. 119 6.2.5. Lateral Drift up to 40
Story Building.. 121
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6.3. Labor and Material Cost. 124 6.3.1. Cost of 10 Story
Building... 124 6.3.2. Cost of 20 Story Building... 126 6.3.3. Cost
of 30 Story Building........................................... 128
6.3.4. Cost of 40 Story Building... 130 6.3.5. Total Cost up to 40
Story Building. 132 6.4. Material Quantities..134
Chapter 7. Conclusions and Recommendations 7.1. Conclusions. 137
7.2. Recommendations... 140
Bibliography... 141 Appendices Appendix A. Structural Floor
Framing Systems Comparisons
A.1. One - Way Solid Slab. 144 A.2. Two - Way Solid Slab 145
A.3. Two - Way Flat Slab.. 146 A.4. Two - Way Flat Plate Slab. 147
A.5. One - Way Joist Slab.. 148 A.6. Two - Way Joist (waffle) Slab
149
Appendix B. Vertical Structural Systems Comparisons
B.1. Moment Frame System... 150 B.2. Diagonal Braced Frame
System.. 151 B.3. Shear Walls System. 152 B.4. Shear Walls and
Frame System... 153 B.5. Tube System 154 B.6. Framed Tube System...
155 B.7. Staggered Truss System.. 156
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List of Tables
Table 2.1: Combined Axial and Bending Stresses for 20 Story
Concrete Moment Frame.................. 10 Table 2.2: Combined
Axial and Bending Stresses for 20-Story Steel Moment
Frame.................. 11 Table 2.3: Allowable Axial Loads in Kips
for Wide Flange (W14)............... 12 Table 2.4: Measuring the
maximum Actual Lateral Drift (Deflection).................. 14
Table 3.1: Environmental Impact of Reinforced Concrete and Steel
beams................. 32 Table 3.2: Soil Types and
Capacity................... 38
Table 4.1: Basic Wind Speed and Pressure..................
50
Table 4.2: Structural Systems Comparisons.....................
68 Table 4.3: Allowable Stress for Wood.................. 70 Table
4.4: Allowable Stress for Steel................ 70 Table 4.5:
Allowable Stress for Masonry.................. 71 Table 4.6:
Allowable Stress for Concrete.................. 71
Table 4.7: Slenderness Ratio................. 73
Table 5.1: Gravity Load Calculations.................. 79 Table
5.2: Wind Loads for 10 Story Building................. 80 Table
5.3: Beams Schedule for A 10 Story Steel Moment
Frame............... 82 Table 5.4: Columns Schedule for A 10 Story
Steel Moment Frame............... 82 Table 5.5: Beams Schedule for
A 10 Story Concrete Moment Frame................ 83 Table 5.6:
Columns Schedule for A 10 Story Concrete Moment
Frame................. 83 Table 5.7: Beams Schedule for A 10 Story
Steel Braced Frame................. 84
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Table 5.8: Columns Schedule for A 10 Story Steel Braced
Frame................... 84 Table 5.9: Braces Schedule for A 10
Story Steel Braced Frame................... 84 Table 5.10: Beams
Schedule for A 10 Story Concrete Shear Wall................. 85
Table 5.11: Columns schedule for a 10 story concrete shear
wall............... 85 Table 5.12: Labor and Material Cost for A 10
Story Steel Moment Frame................ 86 Table 5.13: Labor and
Material Cost for A 10 Story Steel Braced Frame..................
86 Table 5.14: Labor and Material Cost for A 10 Story Conc. Moment
Frame............... 86 Table 5.15: Labor and Material Cost for A
10 story Concrete Shear Wall................. 86 Table 5.16: Wind
Loads for 20 Story Building............... 87 Table 5.17: Beams
Schedule for A 20 Story Steel Moment Frame................ 89 Table
5.18: Columns Schedule for A 20 Story Steel Moment
Frame................. 89 Table 5.19: Beams Schedule for A 20 Story
Concrete Moment Frame.................. 90 Table 5.20: Columns
Schedule for A 20 Story Concrete Moment Frame............... 90
Table 5.21: Beams Schedule for A 20 Story Steel Braced
Frame............... 91 Table 5.22: Columns Schedule for A 20 Story
Steel Braced Frame............... 91 Table 5.23: Braces Schedule
for A 20 Story Steel Braced Frame............... 91 Table 5.24:
Beams Schedule for A 20 Story Concrete Shear Wall.................
92 Table 5.25: Beams Schedule for A 20 Story Concrete Shear
Wall................. 92 Table 5.26: Labor and Material Cost for A
20 Story Steel Moment Frame................ 93 Table 5.27: Labor
and Material Cost for A 20 Story Steel Braced Frame...............
.. 93 Table 5.28: Labor and Material Cost for A 20 Story Conc.
Moment frame............... 93 Table 5.29: Labor and Material Cost
for A 20 Story Concrete Shear Wall................ 93 Table 5.30:
Wind Loads for 30 Story Building............... 94
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Table 5.31: Beams Schedule for A 30 Story Steel Moment
Frame................ 96 Table 5.32: Columns Schedule for A 30
Story Steel Moment Frame................. 96 Table 5.33: Beams
Schedule for A 30 Story Concrete Moment Frame.................. 97
Table 5.34: Columns Schedule for A 30 Story Concrete Moment
Frame............... 97 Table 5.35: Beams Schedule for A 30 Story
Steel Braced Frame............... 98 Table 5.36: Columns Schedule
for A 30 Story Steel Braced Frame............... 98 Table 5.37:
Braces Schedule for A 30 Story Steel Braced Frame............... 98
Table 5.38: Beams Schedule for A 30 Story Concrete Shear
Wall................. 99 Table 5.39: Beams Schedule for A 30 Story
Concrete Shear Wall................. 99 Table 5.40: Labor and
Material Cost for A 30 Story Steel Moment Frame................ 100
Table 5.41: Labor and Material Cost for A 30 Story Steel Braced
Frame.................. 100 Table 5.42: Labor and Material Cost for
A 30 Story Conc. Moment Frame............... 100 Table 5.43: Labor
and Material Cost for A 30 Story Concrete Shear
Wall................ 100 Table 5.44: Wind Loads for 40 Story
Building............... 101 Table 5.45: Beams Schedule for A 40
Story Steel Moment Frame................. 103 Table 5.46: Columns
Schedule for A 40 Story Steel Moment Frame................. 103
Table 5.47: Beams Schedule for A 40 Story Concrete Moment
Frame.................. 104 Table 5.48: Columns Schedule for A 40
story Concrete Moment Frame............... 104 Table 5.49: Beams
Schedule for A 40 Story Steel Braced Frame............... 105 Table
5.50: Braces Schedule for A 40 Story Steel Braced
Frame............... 105 Table 5.51: Columns Schedule for A 40
Story Steel Braced Frame............... 106 Table 5.52: Beams
Schedule for A 40 Story Concrete Shear Wall. 107 Table 5.53:
Columns Schedule for A 40 Story Concrete Shear
Wall.................. 107
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Table 5.54: Labor and Material Cost for A 40 Story Steel Moment
Frame................ 108 Table 5.55: Labor and Material Cost for A
40 story Steel Braced Frame............... 108 Table 5.56: Labor
and Material Cost for A 40 Story Conc. Moment Frame...............
108 Table 5.57: Labor and Material Cost for A 40 Story Concrete
Shear Wall................ 108
Table 5.58: Total Cost Comparison for 10 Story
Building.................. 109 Table 5.59: Total Cost Comparison
for 20 Story Building.................. 109 Table 5.60: Total Cost
Comparison for 30 Story Building.................. 109 Table 5.61:
Total Cost Comparison for 40 Story Building.................. 109
Table 6.1: Lateral Drift Comparison for 10 Story
Building.................. 111 Table 6.2: Lateral Drift Comparison
for 20 Story Building.................. 114 Table 6.3: Lateral
Drift Comparison for 30 Story Building.................. 117 Table
6.4: Lateral Drift Comparison for 40 Story
Building.................. 120 Table A.1: One - Way Solid Slab
Criteria................. 144 Table A.2: Two - Way Solid Slab
Criteria................ 145 Table A.3: Two - Way Flat Slab
Criteria............... 146 Table A.4: Two - Way Flat Plate Slab
Criteria.................. 147 Table A.5: One - Way Joist Slab
Criteria.................. 148 Table A.6: Two - Way Waffle Slab
Criteria.................. 149 Table B.1: Moment Frame System
Criteria............... 150 Table B.2: Diagonal Braced Frame System
Criteria................. 151 Table B.3: Shear Wall System
Criteria.................. 152 Table B.4: Shear Wall and Frame
System Criteria................ 153 Table B.5: Tube System
Criteria............... 154
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Table B.6: Framed Tube System Criteria.................. 155
Table B.7: Staggered Truss System Criteria..................
156
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List of Figures
Figure 1.1: Structural Systems............... 3 Figure 1.2:
Selection of Structural System Process............... 4 Figure 1.3:
Kingdom Tower and Al Faisalih Tower in Riyadh................. 6
Figure 1.4: Hurricane and Buildings Collapse Causing by
Hurricane................. 7 Figure 2.1: Prototype, Perspective,
Plan, and Section............... 9 Figure 2.2: STAAD Pro2005 Logo.
(STAAD Software).................. 10 Figure 2.3: Selection of
Structural Systems and Materials Process............... 13 Figure
2.4: Lateral Drift Under Wind Load............... 14 Figure 3.1:
Case Study Selection Process................ 18 Figure 3.2:
Building Systems Integration................ 20 Figure 3.3: Span
Ranges for Structure Elements.................. 22 Figure 3.4: Span
Ranges for Structure Systems................ 23 Figure 3.5: Gravity
Load Types................. 24 Figure 3.6: Seismic
Waves................ 25 Figure 3.7: Richter Scale
Method.................. 26 Figure 3.8: (a) Surface Waves (b) Body
Waves................. 26 Figure 3.10: Structural Members Under
Vertical and Lateral Loads.................. 29 Figure 3.11:
Schematic Structures (a) Concrete Beam (b) I Steel
Beam............... 31 Figure 3.12: Structure Systems vs.
Height................ 35 Figure 3.13: Thermal Reservoir
Comparisons............... 37 Figure 3.14: End Bearing
Piles.................. 38
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Figure 3.15: Truss (a) vs. Vierendeel (b) Duct
constraints................ 40 Figure 4.1: Wind flow Around a Tall
building.................. 43 Figure 4.2: Relation of Wind Velocity
to Pressure on a Stationary Object.................. 44 Figure 4.3:
General Effects of Wind.................. 46 Figure 4.4: Wind
Pressure on Building................ 47 Figure 4.5: Building (A),
Wind force (Fx), Shear force per level (Vx) Overturn moment (Mx),
Overturn visualized (B)............... 48 Figure 4.6: Wind Speed in
Saudi
Arabia...........................................................................
51 Figure 4.7: Wind Exposures; Inner City, Open area, & Near
ocean................ 52 Figure 4.8: Leeward and Windward Pressure
Distrubution.............................................. 53
Figure 4.9: Kz Graph............... 54 Figure 4.10: Drift in a
Building Subjected to Lateral Wind Forces............... 56 Figure
4.11: Moment Frame Deformation Types.................. 60 Figure
4.12: Moment Frame (A) and Deformation Under Wind Load
(B)............... 61 Figure 4.13: Braced Frame Deformation
Types................ 63 Figure 4.14: Braced Frame (A),
Predominantly Shear Deflection (B) , and Flexural
Mode.................. 64 Figure 4.15: Functions of Shear
Walls.................. 65 Figure 4.16: Shear Walls Types
1................. 66 Figure 4.17: Drift Configuration of Shear
Wall-Frames Structure................ 67 Figure 4.18: Interaction
Between Braced Frame and Moment Frame............... 68 Figure
4.19: Shear Walls Types................ 72 Figure 4.20: Slenderness
Ratio.................. 73
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Figure 4.21: 20 Story Frame Configuration.................. 75
Figure 5.1: 10 Story (130 ft) Height Prototype Frame; Plan (a),
Section (b), Wind and gravity load (c)................ 78 Figure
5.2: Structural Framing Plan With Loads Distribution on Beams for
10 Story Building................. 79 Figure 5.3: Combined Stresses
of Beams for Steel Moment Frame for 10 Story
Building.................. 81 Figure 5.4: Combined Stresses of
Columns for Steel Moment Frame for 10 Story
Building.................. 81 Figure 5.5: Combined Stresses of
Beams and Columns for Concrete Moment Frame for 10 Story
Building................ 81 Figure 5.6: Combined Stresses of Beams
and Columns for Concrete Shear Walls for 10 Story
Building.................. 81 Figure 5.7: Combined Stresses of
Beams for Steel Braced Frame for 10 Story
Building.................. 81 Figure 5.8: Combined Stresses of
Columns for Steel Braced Frame for 10 Story
Building.................. 81 Figure 5.9: Perspective of a 10 Story
Steel Moment Frame.................. 82 Figure 5.10: Perspective of
a 10 Story Concrete Moment Frame................ 83 Figure 5.11:
Perspective of a 10 Story Steel Braced Frame................ 84
Figure 5.12: Perspective of a 10 Story Concrete Shear
Wall.................. 85 Figure 5.13: 20 Story (260 ft) Height
Prototype Frame; Section (a),Wind and gravity load
(b).................87 Figure 5.14: Combined Stresses of Beams for
Steel Moment Frame for 20 Story Building.................. 88
Figure 5.15: Combined Stresses of Columns for Steel Moment Frame
for 20 Story Building.................. 88
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Figure 5.16: Combined Stresses of Beams and Columns for Concrete
Moment Frame for 20 Story Building................ 88 Figure 5.17:
Combined Stresses of Beams and Columns for Concrete Shear Walls for
20 Story Building..... 88 Figure 5.18: Combined Stresses of Beams
for Steel Braced Frame for 20 Story Building...... 88 Figure 5.19:
Combined Stresses of Columns for Steel Braced Frame for 20 Story
Building.................. 88 Figure 5.20: Perspective of a 10
Story Steel Moment Frame.................. 89 Figure 5.21:
Perspective of a 20 Story Concrete Moment Frame 90 Figure 5.22:
Perspective of a 20 Story Steel Braced Frame 91 Figure 5.23:
Perspective of a 20 Story Concrete Shear Wall.................. 92
Figure 5.24: 30 Story (390 ft) Height Prototype Frame; Section (a),
Wind and Gravity Load (b). 94 Figure 5.25: Combined Stresses of
Beams for Steel Moment Frame for 30 Story
Building.................. 95 Figure 5.26: Combined Stresses of
Columns for Steel Moment Frame for 30 Story
Building.................. 95 Figure 5.27: Combined Stresses of
Beams and Columns for Concrete Moment Frame for 30 Story Building
95 Figure 5.28: Combined Stresses of Beams and Columns for Concrete
Shear Walls for 30 Story Building..... 95 Figure 5.29: Combined
Stresses of Beams for Steel Braced Frame for 30 Story Building.....
95 Figure 5.30: Combined Stresses of Columns for Steel Braced Frame
for 30 Story Building..... 95 Figure 5.31: Perspective of a 30
Story Steel Moment Frame..... 96 Figure 5.32: Perspective of a 30
Story Concrete Moment Frame... 97
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Figure 5.33: Perspective of a 30 Story Steel Braced Frame... 98
Figure 5.34: Perspective of a 30 Story Concrete Shear Wall...... 99
Figure 5.35: 40 Story (520 ft) Height Prototype Frame; Section (a),
Wind and Gravity Load (b). 101 Figure 5.36: Combined Stresses of
Beams for Steel Moment Frame for 40 Story
Building.................. 102 Figure 5.37: Combined Stresses of
Columns for Steel Moment Frame for 40 Story Building.. 102 Figure
5.38: Combined Stresses of Beams and Columns for Concrete Moment
Frame for 40 Story Building 102 Figure 5.39: Combined Stresses of
Beams and Columns for Concrete Shear Walls for 40 Story
Building..... 102 Figure 5.40: Combined Stresses of Beams for Steel
Braced Frame for 40 Story Building...... 102 Figure 5.41: Combined
Stresses of Columns for Steel Braced Frame for 40 Story
Building.................. 102 Figure 5.42: Perspective of a 40
Story Steel Moment Frame.................. 103 Figure 5.43:
Perspective of a 40 Story Concrete Moment Frame 104 Figure 5.44:
Perspective of a 40 Story Steel Braced Frame 105 Figure 5.45:
Perspective of a 40 Story Concrete Shear Wall..................
107
Figure 6.5: Lateral Drift in Inches for a 20 Story Building...
111 Figure 6.1: Lateral Drift in Inches for a 10 Story Building...
112 Figure 6.2: Lateral Drift of 10 Story Building Under Wind
Pressure... 112 Figure 6.3: Lateral Drift Reduction as Percent of
Allowable for 10 Story Building.. 113 Figure 6.4: Lateral Drift
under Wind Pressure for 20 Story Building... 114
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Figure 6.7: Lateral Drift Reduction as Percent of Allowable for
20 Story Building.................. 115 Figure 6.8: Lateral Drift
under Wind Pressure for 30 Story Building... 116 Figure 6.9:
Lateral Drift in Inches for a 30 Story Building... 117 Figure 6.10:
Lateral Drift Reduction as Percent of Allowable for 30 Story
Building...... 118 Figure 6.11: Lateral Drift under Wind Pressure
for 40 Story Building... 119 Figure 6.12: Lateral Drift in Inches
for a 40 Story Building... 120 Figure 6.13: Lateral Drift Reduction
as Percent of Allowable for 40 Story Building...... 121 Figure
6.14: Lateral Drift in Inches for Steel Moment Frame..... 122
Figure 6.15: Lateral Drift in Inches for Concrete Moment
Frame...... 122 Figure 6.16: Lateral Drift in Inches for Concrete
Shear Wall..... 123 Figure 6.17: Lateral Drift in Inches for Steel
Braced Frame... 123 Figure 6.18: Cost Comparisons Per ft for 10
Story Building..... 124 Figure 6.19: Percentage of Cost Reductions
for 10 Story Building.... 125 Figure 6.20: Total Cost of 10 Story
Building...... 125 Figure 6.21: Cost Comparisons Per ft for 20
Story Building. 126 Figure 6.22: Percentage of Cost Reductions for
20 Story Building.... 127 Figure 6.23: Total Cost of 20 Story
Building...... 127 Figure 6.24: Cost Comparisons Per ft for 30
Story Building. 128 Figure 6.25: Percentage of Cost Reductions for
30 Story Building129 Figure 6.26: Total Cost of 30 Story
Building.................. 129 Figure 6.27: Cost Comparisons Per ft
for 40 Story Building. 130
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xx
Figure 6.28: Percentage of Cost Reductions for 40 Story Building
131 Figure 6.29: Total Cost of 40 Story Building..................
131 Figure 6.30: Total Cost for Concrete Moment Frame. 132 Figure
6.31: Total Cost for Steel Moment Frame.... 133 Figure 6.32: Total
Cost for Concrete Shear Wall 133 Figure 6.33: Total Cost for Steel
Braced Frame.................. 134 Figure 6.34: Steel Weight for
Steel Moment Frame 135 Figure 6.35: Steel Weight for Steel Braced
Frame.. 135 Figure 6.36: Concrete Volume for Concrete Moment
Frame.................. 136 Figure 6.37: Concrete Volume for
Concrete Shear Wall. 136
Figure 7.1: Lateral Drift Comparisons for Different Structural
Systems and Heights... 137 Figure 7.2: Total Cost Comparisons for
Different Structural Systems and Heights... 139 Figure A.1:
Perspective of One-Way Solid Slab 144 Figure A.2: Perspective of
Two-Way Solid Slab... 145
Figure A.3: Perspective of Two-Way Flat Slab..... 146 Figure
A.4: Perspective of Two-Way Flat Plate Slab.... 147 Figure A.5:
Perspective of One-Way Joist Slab..... 148 Figure A.6: Perspective
of Two-Way Waffle Slab..... 149 Figure B.1: Perspective of Moment
Frame System.... 150 Figure B.2: Perspective of Diagonal Braced
Frame System... 151 Figure B.3: Perspective of Shear Wall System...
152 Figure B.4: Perspective of Shear Wall and Frame System.....
153
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xxi
Figure B.5: Perspective of Tube System..... 154 Figure B.6:
Perspective of Framed Tube System... 155 Figure B.7: Perspective of
Staggered Truss System... 156
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xxii
Abstract
This thesis proposes procedures and guidelines for selection of
optimum structural
systems and materials in two stages. Stage one is based on a
list of criteria, including
architectural considerations. Stage two evaluates selected
systems and materials for
optimum performance of criteria considered critical for a given
project. A tall office
building in Dammam Saudi Arabia is used as case study to compare
three structural
systems: moment frame, braced frame, and shear wall; as well as
two materials: concrete
and steel. The case study considers four building heights: 10,
20, 30, and 40 stories. The
STAAD Pro 2005 software is used to analyze these systems
according to allowable stress
requirements for an objective function to minimize drift, at
minimal cost for wind speed
of 90 miles per hour. Shear wall is the optimum structural
system and concrete the
optimum material to minimize lateral drift at minimum material
and labor costs.
Keywords: lateral drift, wind load, IBC 03, allowable stress,
STAAD Pro
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1
Chapter 1 Introduction
1.1 Introduction This chapter introduces the objectives, scope
of study and a brief introduction to
structural systems, selection of structural systems, and
selection of criteria. In addition, it
includes an analysis of tall buildings in Saudi Arabia and wind
load considerations.
1.2 Objective and Scope of Study The objective of this thesis is
to develop a formal process and guidelines to select optimal
structural systems and material which minimize lateral drift in
tall buildings in Saudi
Arabia in relation to cost.
The process involves three stages:
Stage 1: Pre-select systems based on a list of criteria
Stage 2: Select a case study system, considering moment frame,
braced frame, shear wall
Stage 3: select material, considering steel or concrete
This process is conducted for tall buildings of various heights
in Dammam, Saudi Arabia.
The STAAD software is used to analyze theses systems according
to the allowable stress
requirements for an objective function to minimize drift, at
minimum material and labor
costs for maximum wind speed of 90 miles / hour.
1.3 Selection Steps
1- Pre-select appropriate systems based on a list of
criteria
2- Test structural systems (moment &braced frame, shear
wall) under lateral load
3- Compare drift of each structural system and material to
select the optimum one.
4- Reduce the basic labor and materials costs.
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2
1.4 Structural Systems and Materials
A structural system is defined as the main part of the building
which carries and transfers
the loads, both vertical and lateral, safely to the soil through
the foundation. Structural
systems consist of many elements, including: floor slabs, decks,
joists, beams, girders,
shear walls, columns, braces, and foundations. Structure systems
involve horizontal and
vertical systems. Horizontal systems include bending resistant
systems (beam systems,
Vierendeel, folded plate, cylindrical shell); axial resistant
(truss, space truss, tree); form
resistant (arch, vault, dome, grid shell, HP shell, etc.);
tensile resistant (suspended and
stayed systems, etc.). Vertical systems include: moment frame,
braced frame, shear wall,
cantilever, framed tube, braced tube, bumbled tube, suspended
high-rise, etc. (Fig. 1.1).
Each system has advantages as well as different purposes. For
example, a moment frame
is recommended for use in office buildings in order to provide
free flexible space for
rental purpose. Shear walls are good to use for hotels and
apartments to provide lateral
force resistance as well as sound transmission isolation and
unit separation. Furthermore,
each structural system has a different level of stiffness. For
example, a moment frame is
more flexible than a braced frame system. In contrast, a shear
wall system is more rigid
than a braced frame system. Shear walls and braced frames are
better to resist wind load,
while ductile moment frames are better to resist seismic
load.
-
3
(a) (b)
(c) (d)
Figure 1.1: Structural systems (a) Moment frame, (b) braced
frame, (c) shear wall, (d) Cantilever. (Schierle, 2006, p 3-10)
There are also several alternative structural building
materials: steel, concrete, masonry,
wood, aluminum, and fabric. Each material has different
properties as well as different
purposes. For example, wood buildings are the most popular
buildings in the United
States because they are light, minimize seismic load, as well as
wood is readily available
and relatively cheap compared to concrete and steel . In
contrast, concrete buildings are
the most popular buildings in Saudi Arabia because wood is not
available and concrete is
good to resist wind load. Concrete is also cheaper than steel
which is less available.
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1.5 Selection of Structural Systems
The selection of structural system is sometimes based on
personal experience or
perception without being evaluated as it should be to provide
advantage for the project.
The conceptual selection process provides an orderly way to
determine and review vital
criteria which leads to the selection of the optimum structural
system (CRSI 1997 p2).
The structural system should be integrated and accommodated to
other building systems,
like: architectural, mechanical, electrical, and building
services.
However, the selection of the structural system is often passed
through many processes,
as shown in figure 1.2. At the beginning of the process the
criteria and requirements
should be determined. The second step is applying different
structural systems to the
criteria and requirements. The third step is testing and
evaluating the performance of each
structural system. The forth step is developing and modifying
the tested system and
retesting as well as evaluating it again. The last step is
selecting the optimum structural
system and material.
4
Figure 1.2: Selection of structural system process
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5
1.6 Selection Criteria The selection process is very wide in
scope and contains every aspect that could affect
the selection of structural system. Determining the required
criteria depends on owner
needs, project constraints, and project requirements (CRSI 1997
p3). A smart or an
optimum structural system is that system which achieves most of
the required criteria.
There are many critical criteria that affect the selection of
structural systems and
materials, and this thesis proposes 40 of them like: gravity
load, lateral load (wind and
seismic), climate conditions, labor and material costs, code
requirements, building
location, building height limit, sustainability (durable and
recyclable), strength, stiffness,
stability, and synergy. For example, building location is a
significant criterion which
affects the selection of material. In Saudi Arabia, the most
popular building material is
concrete; while wood is not available and steel is very
expensive. The main investigated
criterion is minimizing the lateral drift in tall buildings in
Saudi Arabia in order to
provide occupant comfort and protect them and the properties.
The secondary criterion is
minimizing labor and material cost. Chapter three shows the list
of selection criteria and a
brief description for each one.
1.7 Tall Buildings in Saudi Arabia
The Kingdom of Saudi Arabia is a rapidly developing modern
country, containing a rich
variety of building structure systems and materials, such as
concrete and steel. In order to
support building industrialization in Saudi Arabia, the
government of Saudi Arabia hired
many famous architects and structural engineers, such as Norman
Foster, to design some
vital buildings. In large cities of Saudi Arabia like Riyadh,
Jeddah, and Dammam, the
-
population is rapidly increasing. This requires a rapid increase
of building construction in
order to meet peoples needs. For example: in Riyadh, the capital
of Saudi Arabia, the
population is approximately 4.3 million people, which requires a
large land area. (The
purpose behind building high-rise buildings is because there is
a shortage in land
availability so the land cost is very high. Most people cannot
afford these land prices and
one solution is to build high-rise buildings). Figure 1.3 shows
the most popular highrise
building in Riyadh. These buildings became marks land of Saudi
Arabia and are listed
with the highest buildings in the world. These buildings have
different occupancies, like
offices, hotels, shopping centers, and apartments in order to
meet peoples needs. Hence,
because of the high demand to build more high-rise buildings in
Saudi Arabia, this thesis
will investigate the structural performance of tall buildings in
Saudi Arabia in order to
select the best structural systems and material which improve
the performance of the
building to resist the lateral force like strong winds and
earthquakes.
(a) (b)
Figure 1.3: (a) Kingdom tower, (b) Al Faisalih tower in Riyadh
(http://www.moudir.com/vb/showthread.php?t=95655)
6
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1.8 Wind Load Considerations
Wind load is a critical force that causes many disasters, as can
be seen in Figure 1.4.
Because in Saudi Arabia wind load is more critical than seismic
load, this thesis investigates
wind effect on tall buildings in Saudi Arabia. The peak wind
speed in Dammam city is
about 90 mph (miles per hour). Wind load increases with height
on tall buildings. Wind
causes lateral deflection (drift) on tall buildings and requires
careful consideration to control
drift. To minimize lateral drift in tall buildings it is
necessary to select the optimum
structural systems and materials which help to minimize drift.
Controlling drift is vital to
provide occupant comfort and avoid motion sickness. Furthermore,
large drift may endanger
life and incur loss of property or even cause building
collapse.
(a) (b)
Figure 1.4: (a) Hurricane, (b) buildings collapse causing by
hurricane
(http://www.fws.gov/home/hurricane/)
7
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8
Chapter 2 Research Methodology
2.1 Introductions This chapter describes the research
methodology, such as data collection and analysis. In
addition, it shows the various tools which are used.
2.2 Data Collection Methods The thesis data is collected from
different sources which are: reference books, published
papers, articles, interviews, lectures, previous MBS thesis, and
some working drawings.
Since this thesis investigates tall buildings in Saudi Arabia,
some data is collected from
consulting offices in Dammam, Saudi Arabia: for example, wind
speed, code
requirements, and the methodology of design. The official
building code used in Saudi
Arabia is the International Building Code IBC 03. Some
information about material and
labor cost is collected through phone calls with AL Zamil steel
factory as well as some
construction companies in Saudi Arabia. In addition, one of the
vital methods of
collection data interviewed the thesis committee members: Prof.
Schierle, Prof. Noble,
Mr. Vergun, Prof. Speigehalter, and Dr. ALSatari.
2.3 Thesis Tools and Testing Model 2.3.1 Testing Model: The
thesis tested a large part of the building as prototype instead of
testing the whole
building; however, the test is done for an office building
because the function of the
building could be accommodated with many types of structural
systems, including
moment frame, braced frame, and shear wall. The typical story
height for office buildings
-
is about 13 feet. Width and length of the horizontal plan are
determined by program
needs and the code requirements for expansion joints. The
maximum distance for the
expansion joint should not exceed 30 m or (100 feet). The plan
dimension of the tested
proptotype is 100 feet 100 feet. As shown in fig. 2.1 the plan
consists of three equal
bays (33.3x33.3 ft). Furthermore, the first suggested height of
the building is determined
by fire safety requirements in Saudi Arabia; the minimum
considered height of a high rise
building is about 10 floors. The investigation is for 20, 30,
and 40 stories.
(a) (b) (c)
Figure 2.1: Prototype: (a) perspective, (b) plan, (c)
section
2.3.2 STAAD Pro 2005 Software
The Structural Analysis and Design program is the most popular
structural software in
Saudi Arabia; it is used in most of the structural consulting
offices and the universities of
Saudi Arabia. This program is used to analyze and design all
types of structural system
and material. Therefore, this program is used as the main tool
of this investigation.
9
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Figure 2.2: STAAD Pro2005 logo. (STAAD Software)
2.4 Design Methods The allowable stress design method is used
for schematic structural design and analysis
material strength: concrete 9.0 ksi, steel: 50 ksi. Structural
members are designed to meet
the allowable stresses, using safety factors of 45% for concrete
and 60% for steel (4 ksi
concrete, 30 ksi steel beam; 25 ksi steel columns due to
buckling) In order to minimize
structural elements size, and to reduce the cost. For example,
as shown in table 2.1, the
combined axial and bending stresses for concrete beams and
columns meet the maximum
allowable stress 4000 psi (4 ksi).
Table 2.1: Combined axial and bending stresses for 20 story
concrete moment frame
10
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As can be seen in table 2.2 the combined axial and bending
stresses for a 20 story steel
moment frame for 33.33 ft steel beams are 29,257 psi while the
maximum allowable
stress is 30,000 psi (30 ksi). As for 13 ft steel columns as
shown in table 2.2, the
combined stresses 24,415 psi while the maximum allowable stress
is 25,000 psi (25 ksi)
for buckling.
Table 2.2: Combined axial and bending stresses for 20-story
Steel Moment frame
Member sizes are based on combined wind and gravity loads. Beam
and column sizes
vary every two floors as shown in the tables. Wide flange steel
columns and beams are
used for steel buildings in this test (W14 for columns and W18
for beams) because they
are common in Saudi Arabia and United States. As shown in table
2.3 the allowable axial
loads in kips for wide flange columns (w14) for different yield
strength as well as
different weight. However, to check the efficiency of strength
for selected section, the
allowable axial loads should be checked per inch. For example,
the allowable axial loads
11
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Selected section (50 ksi), kL = 13:
W14x176, A=51.8 in, Pallowable = 1347 kips (Use W14x176 )
Allowable stress = 1347 / 51.8 = 26 ksi > 25 ksi, O.K
12
Table 2.3: Allowable axial loads in kips for wide flange
(W14)
(AISC, 1991, p3-22) 2.5 Data Analysis Method 2.5.1 Selection of
Structural System Method Selection of structural system is done
through many processes, as shown in figure 2.4.
For example, considering two materials (steel and concrete),
three structural systems
(moment frame, braced frame, and shear wall); this process
implies four combinations of
structural systems and materials for each building height. Each
material and system
-
combination is passed through a criteria process to minimize
lateral drift (main criteria)
as well as minimizing labor and material costs (secondary
criteria). All material and
structural system combinations are entered to the design
evaluation of STAAD Pro 2005.
Comparing all result leads to the selection of the optimum
structural system and material.
Figure 2.3: Selection of structural systems and materials
process
2.5.2 Drift Measuring Method
The lateral drift is measured at each level after defining
member size for strength to
assure the actual lateral drift is less than the maximum
allowable drift (h/200). As can be
seen in fig. 2.4 which shows lateral drift under wind load, the
measurement is taken at
each floor as well as comparing the actual lateral drift with
the maximum allowable drift.
Table 2.4 shows the measurement of the maximum actual lateral
drift (deflection) in
STAAD pro software.
13
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14
Figure 2.4: Lateral drift under wind load
Table 2.4: Measuring the maximum actual lateral drift
(deflection)
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15
Chapter3 Selection Criteria
3.1. Introduction The structural system is considered as the
most vital system in the building for many
reasons. First, it usually has the highest cost compared to
other building systems cost.
Second, the structural system is required for a building to
stand up. The other building
systems should be accommodated and adapted to it, for example,
the mechanical
equipment, air conditioning ducts and other services must be
integrated with the
structural system and elements. Finally, the structural system
should save occupants and
properties from natural forces, such as gravity, wind and
seismic loads.
The selection criteria method is very wide in scope and includes
not only structural
aspects but also architectural considerations. Determining the
required criteria depend
on owner needs, project constraints, and project requirements
(CRSI 1997, p3).
Architects and engineers should select the structural system
according to criteria defined
jointly by building owners, architects and structural engineers
following are 42 criteria
proposed to select structural systems and materials.
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16
3.2. Proposed General Criteria List 1- Material cost
2- Labor cost
3- Integration and synergy
4- Ease of construction
5- Span limits
6- Gravity load
7- Lateral load (wind and seismic)
8- Noise and vibration control
9- Fire safety and protection
10- Sustainability (durability and recyclable)
11- Strength, Stiffness, Stability, and Synergy
12- Corrosion and moisture resistance
13- Maintenance cost (life cycle cost)
14- Material transportation
15- Material availability (resources)
16- Design possibilities (structural freedom)
17- Environmental Impact and energy consumption of
production
18- Building type (function of building)
19- Building location
20- Building height limit
21- Code requirements
22- Site conditions (access, storages)
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17
23-Technology availability
24- Energy efficiency & thermal mass
25- Soil class and topography (flat or sloping)
26- Planning policy and constrains
27- Morphology
28- Weather condition
29- Security
30- Quality control
31- Exterior cladding system
32- Story height
33- Future modification like opening
34- Speed of construction
35- Resale and payback
36- Leverage cash flow
37- Managing change
38- Healthy living & indoor air quality
39- Appearance
40- Building volume
41- Reduced Insurance Premiums
42- Building configuration
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3.3. Case Study Selection Process
Figure 3.1: Case study selection process
18
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19
3.4. Structural Criteria 3.4.1. Material Cost
Material cost affects the selection of structure system.
Material cost depends on many
factors like availability, energy consumption for production,
abundance or shortage and
economic condition of the country. Obviously, local material
cost will be much cheaper
than imported material. For example, in Saudi Arabia, the Hadeed
Company which is
considered the biggest provider of steel in the Middle East
imports steel from Mexico
and Brazil; which causes steel costs in Saudi Arabia to be more
expensive than steel
prices in the United States (Mohammed, 2006). On the other hand,
concrete cost in
Saudi Arabia is much cheaper than concrete cost in the United
States because of the
resources and the production abundance as well as the labor
cost, notably for formwork.
3.4.2. Labor Cost
Labor cost depends on many factors, like location, the skill of
labor, complexity of the
work, as well as the economical situation of the country.
However, the labor cost also is
influenced by the same factors that affect the material cost.
For example, in poor
countries the labor cost is less than the labor cost in rich
countries. In addition, the
skilled labor cost is much higher than unskilled labor cost. For
instance, the Saad
Company, a construction company in Saudi Arabia, pays about $500
per month for a
skilled mason while they pay about half as much for unskilled
masons, i. e. $250 per
month (Eng. Mustafa 2006). Furthermore, the hourly labor rates
differ from country to
country. For example, the hourly rate for skilled mason in Saudi
Arabia is $5 while the
rate for a skilled bricklayer in the United States is $36.81
(ICEC 20 January 2006).
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3.4.3. Integration and Synergy
A structural system should be accommodated and integrated with
other building systems.
For example, as shown in figure 3.2, a structural floor slab,
designed as one-way joist rib-
slab, the gaps between the joists are used to pass the services,
like air conditioning ducts,
lighting, electric wires and water pipes. Furthermore, to avoid
the obstacles of the main
girder, all girders are designed to be inverted and hidden beam
in order to ease the
services passage under the beam. In addition, the structural
module is designed in
correlation with the architectural module, which provided the
interior partition walls
exactly over the slab joist in order to avoid slab shear
over-stress.
Figure 3.2: Building systems integration.
3.4.4. Ease of Construction
Time means cost in construction. Therefore, engineers should
select the fastest and
easiest construction system to save the time and cost but
provide quality control. The ease
of construction depends on many factors like labor skills,
design form and the type of
20
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21
materials. For example, the labor skills can control the time
and quality of the work.
Skilled labor can accomplish higher quality than unskilled
labor. Also skilled labors need
less time than unskilled which will reduce the project cost. In
addition, the design form or
shape will affect the ease of construction as well. For example,
formwork for round
columns costs less than square columns in the US.
Also, the type of material affects the ease of construction. For
example, in the United
States, steel usually costs less than concrete because it is
prefabricated while concrete
requires formworks and much time.
3.4.5. Span Limits
The span limit affects the stiffness of a system. For example,
short spans are stiffer than
long spans. In addition, different materials have different span
limits as shown in figures
3.3, 3.4. For example, steel frames have longer span capacity
than concrete frames.
Hence, the span selection is affected by many factors like
materials type, structural
systems type, building type. There is a strong relationship
between the span and the
thickness of members. For instance, when the span increases the
thickness will increase
as well. Furthermore, increasing the span will increase the
cost. On the other hand,
minimizing the span much than the normal will increase the
material quantity as well as
the cost (Othman, 2002). Hence, the selection of span should
moderate the balance of
the long or short span. Figure 3.3 shows span limits and
span/depth ratios for structure
elements and materials. Figure 3.4 shows span limits and
span/depth ratios for structure
systems and material.
-
Figure 3.3: Span ranges for structure elements. (G G Schierle,
2006, p E-2)
22
-
Figure 3.4: Span ranges for structure systems. (G G Schierle,
2006, p E-3)
23
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3.4.6. Gravity load
Structural systems should be able to carry and resist vertical
gravity load. There are
many types of gravity load like dead load, and live load which
includes snow load.
Gravity load depends on many factors like building location,
building occupancy,
structural material and structural system. For example, in
regions without snow load,
like Saudi Arabia, the building structure should be designed for
dead and nominal live
load. In contrast, in mountain areas like Switzerland the
building should be designed to
resist actual snow load. Mountain snow load may be about 20
times greater than the
nominal load in an area without snow load (Schierle, 2006).
Figure 3.5 shows various
types of gravity loads, like: Dead load (1), Live load (2),
Distributed load (3), Uniform
distributed load (4), and Concentrated load (5).
Figure 3.5: Gravity load types (Schierle, 2006, p 2-2)
24
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3.4.7. Seismic Load
Earthquakes cause waves that transfer through underground layers
until they reach to the
ground surface. These waves affect building structures by
shaking building foundations.
Consequently, the building will respond to this motion. Seismic
waves are defined by two
terms as can be seen in figure 3.6. The first term is the period
which is shown as
horizontal line and defined as the time of one wave cycle and
considered the most critical
issue. For example, a building with a period that is resonant
with the ground period could
even collapse. The second term is the amplitude shown as
vertical ordinate, defined as
the displacement of a wave perpendicular to the direction it
moves (Schierle, 2006, p 9-
12).
Figure 3.6: Seismic waves (Schierle, 2006, p.9-12)
The earthquakes affect depends on many factors. For instance:
the earthquakes
magnitude which are measured by the Richter scale. The Richter
scale created by Charles
Richter in 1935 at the California Institute of Technology
observes and measures the
earthquake magnitude (Schierle, 2006, p. 9-12). Figure 3.7
defines the Richter
magnitude as follows: Left line plots earthquake distance, right
line plots amplitude
recorded on a seismograph; center line plots Richter Magnitude;
defined by a line
connecting distance to the amplitude. For example, magnitude 4.5
is minor earthquake,
while 7.0 is a violent one. 25
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Figure 3.7: Richter scale method (Schierle, 2006, p. 9-12)
There are several types of seismic waves (Fig. 3.8). For
example, body waves consist of
P waves (Primary waves) that travel at high speed of 42,000
km/h), and S waves
(Secondary waves) that vibrate normal to the wave direction and
affect the building by
dancing action. In addition, there are surface waves: Love waves
and Raleigh waves.
Figure 3.8: (a) Surface waves (b) Body waves (Schierle, 2005,
p6)
http://www.usc.edu/dept/architecture/mbs/struct/seismic/files/eq-ibc.pdf
26
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27
Seismic force affects the building as base shear, which
basically follows Newtons law:
F= m a (force = mass x acceleration) (Schierle, 2006, p.
9-12).
Due to this equation, structural engineers tend to minimize
building mass and maximize
ductility (Schierle, 2006, p. 9-12). Therefore, to minimize
building weight, requires
selecting lightweight materials and minimize structural members.
Building design should
resist seismic forces to protect the building, people and
property. Most people think that
rigid and strong buildings are best to resist seismic load.
However, they are absolutely
wrong: rigid buildings are subject to greater seismic forces
than ductile ones.
3.4.8. Noise Control
The selected structural material should be able to isolate the
noise in buildings. For
example, in courthouses, hospitals, apartments and office
buildings the selected material
should prevent or reduce sound transmission in order to provide
privacy. Concrete
buildings have good sound rating according to standardized test
(PCA & CRSI, p7).
Because concrete has high mass and density, it has excellent
sound isolation, sound
absorption, and sound transmission reduction (PCA & CRSI,
p7). For example, in
apartment buildings, the apartments should be separated by party
walls to reduce sound
transmission. The party walls can also be shear walls and
provide fire proofing. In
addition, concrete structures can resist vibration and
electrical interference especially the
high-density (PCA & CRSI, p7).
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28
3.4.9. Fire Safety
Fire safety is a critical issue to select the structure
material. For example, concrete is
considered the best material to resist fire, compared to steel
which requires fire proofing
to resist fire.
Steel starts to lose its strength at any temperature more than
300C and begins to
decrease strength at stable rate at about 800C. The melting
temperature of steel is about
1500C (Colin Bailey). Hence, steel requires fire proofing
(spray-on or other fire
proofing).
Concrete has low thermal conductivity, 50 times lower than
steel. In addition, it heats so
slowly because of the density of aggregate and cement. Therefore
concrete is ranked the
best fire resistant material (Colin Bailey). Hence, concrete
does not require fire
protection like steel.
3.4.10. Sustainability (Durable and Recyclable)
Structural systems and materials should provide durability and
sustainability to protect the
environment. Concrete is considered a natural material and
widely available. For
example, the limestone, sand and clay, the main source of
Portland cement production,
are almost without limit. In addition, fly ash from coal
burning, gravel, sand, and crushed
stone are the main source of aggregate. Furthermore, the cement
manufacturing process
uses combustible waste and tires as a fuel source (Publication
& Communication LP
2006). Recycling of steel in the United States every year is
more than recycling of
aluminum, plastic and glass combined with the industry's
overall. The recycling of steel
rate is 64 %.( America Global Foundation 1996-2004). Each year,
steel recycling saves
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energy equivalent to powering about one-fifth of the households
in the United States
(about 10 Million homes) for one year (America Global Foundation
1996-2004). Each
ton of recycled steel saves about 1.400 pounds of coal, 2,500
pounds of iron, and 120
pounds of limestone (America Global Foundation 1996-2004).
3.4.11. Strength, Stiffness, Stability, and Synergy
This criterion is considered a most significant issue to select
the structure system and it
depends on many factors like types of loads, height of building,
span limit and material
specification. As can be seen in the figure 3.9, the structure
system should satisfy:
1- Strength to avoid and resist breaking.
2- Stiffness to avoid extreme deformation.
3- Stability to resist and avoid structural collapse.
4- Synergy to support and integrate the architectural
design.
Figure 3.10: Structural members under vertical and lateral loads
(Schierle, 2006, p.3-2)
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3.4.12. Corrosion and Moisture Resistance
Corrosion resistance greatly depends on the type of material.
Carbon dioxide in the air is
the main reason for corrosion, and corrosion is causing
reduction of the lifespan of
structures. However, concrete ranks as the best material to
resist corrosion and moisture
compared to other materials because of its density and mass. For
example, concrete
protects steel bars from corrosion. Structural concrete members
should be designed to
meet the code requirements to provide corrosion protection for
steel bars. Exposed steel
may be protected by galvanizing, painting, or epoxy.
3.4.13. Material Transportation
Material should be selected locally in order to reduce
transportation cost and to ensure
getting it on time. Cast in place concrete requires less
transportation than steel, which
requires prefabrication in a shop while concrete is cast and
mixed on site which requires
only ready-mix transportation. Transportation costs depend on
the distance between the
project and factory. For instance, imported material will
increase shipping costs and may
causing delay in construction schedule which will affect the
cost of project. In contrast, if
the project is closed to the factory will be more economical and
sustainable.
Transportation will also control and limit element size. Hence,
transportation affects the
selection of structural materials.
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3.4.14. Environmental Impact and Energy Consumption
Reduction of environmental pollution or impact is a new policy
required, for a green
building and healthy environment. Before selection of structural
material one should have
enough knowledge about the different materials and their
environmental impacts. For
example, one study investigated two different types of
structural beam. One of them is
reinforced concrete beam and the other is I- steel beam as shown
in figure 3.11.
Figure 3.11: Schematic structures (a) concrete beam (b) I steel
beam. (Leslie and Jonathan p209)
This study was done using the ATHENA database and computer
program to study: Water
pollution, air pollution, solid waste, energy consumption,
resource use, and global warming
potential. The investigation was done in Canada, which has the
same cost and material
availability as the United States (Leslie and Jonathan p207).
The test results show in table
3.1 resource use of about 48.85 kg reinforcement concrete and
about 18.69 kg of steel. Table
3.1 also shows concrete and steel produced the same high mount
of carbon dioxide, and
produced the same amount of solid waste as well. Steel produced
3 times more water
pollution than concrete. Steel also produced more air pollution
than concrete. Finally, the
energy consumption for steel is much higher than the energy
consumption of concrete.
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Hence, the production of concrete is better than steel because
it is consuming less energy
and less environmental impact (Leslie and Jonathan p 209).
Table 3.1: Environmental Impact of reinforced concrete and steel
beams
(Leslie and Jonathan p210) 3.4.15. Low Maintenance Cost
The initial cost is very important to select structural material
but the running cost, or
maintenance cost is also important. To estimate initial cost is
relatively easy but to predict
running cost is more difficult. Even though, the life span of
concrete buildings is expected
to be longer than that of steel buildings, whether steel and
concrete are required periodic
maintenance and inspection (Tim Lease, P.E. 2003). For example,
concrete should be
isolated from water to prevent water penetration to reach the
steel bars that causes corrosion.
On the other hand, steel needs also painting, and maintaining
the fireproofing and corrosion
resistance, which causes steel failure. (Tim Lease, 2003).
3.4.16. Design Possibility
The shape and size of buildings and structural elements is one
of the most vital issues to
determine the type of structural material. Concrete can have any
form since concrete seeks
the form (Madsen 2005). In addition, concrete allows adding an
extra floor or any
horizontal extension as well. Furthermore, concrete could be
switched from another type of 32
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material like steel. For example, the New York City developer
built Hotel & Tower at the
former Chicago Sun-Times site. This building switched from
structural steel to concrete so
that two additional stories could be added to the 1,125-foot
building. Also, the concrete slab
could be a flat slab which does not require beam space and thus
will provide extra clear
height for each floor (Madsen, 2005). On the other hand, steel
could be used for large span
projects while concrete is recommended for short spans. Steel
can provide extra clear height
because the element size is much less than concrete (Madsen,
2005).
3.4.17. Material Availability
Selection of a local structural material is an axiomatic issue
because imported material will
increase the cost because of shipping costs and limitation of
transportation. However, the
material availability differs from country to country. For
example, in Saudi Arabia concrete
is the most available material because the source of cement,
aggregate, and sand are
provided while steel considered as imported material from Mexico
and Brazil. In contrast,
the United States considered as one of the main producer of
steel in the world. Even
thought, steel cost has increased in the last two years America
is still able to produce about 6
million tons per year (Madsen, 2005). The total usage per year
in the United States is about
4 million tons in the field of construction. Therefore, 2
million tons per year is considered
as redundant. On the other hand, most of states had shortage of
cement in 2004 because of
event like the Florida hurricanes. Some of the United States
have many companies who
produce cement, and thus build most of building of concrete.
Cement companies will
increase by 2008 in these regions (Madsen, 2005).
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3.4.18. Building Type
Selection of structural system and material depends greatly on
the building function. For
example, for factories or large stores the best system is a long
span steel frame, while short
spans are good for housing and hospital buildings. Office
buildings are better with moment
frame or braced frame in order to provide flexibility for
partitions. By contrast, apartment
buildings require party walls to provide privacy, sound
insulation, and fire resistance.
Courthouses and hospitals require the best material for noise
isolation.
3.4.19. Building Location
Building location also affects selection of structural system
and material. For example, if the
building is located in seismic zone, the building should be of
lightweight material in order to
minimizing building mass. In contrast, heavyweight material is
bets in hurricane zones in
order to maximize building mass to resist the wind load.
Location by country will also affect
the selection of materials. For example, in Saudi Arabia it is
better to use concrete in order
to resist the wind load and reduce cost while wood or steel are
better in the United States
because these resources are abundant. Furthermore, each country
has its own building code,
constrains, and policies which are different in each
country.
3.4.20. Building Height Limit
This criterion is also a significant criteria to select
structural systems and materials. Fazlur
Khan (Fig. 3.12) defined optimal structure system for various
building heights, defined by
number of floors. Hence, building height depends on factors like
structural system,
structural material, and drift control.
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Figure 3.12: Structure Systems vs. Height (Schierle, 2006, p.
9-15)
3.4.21. Code Requirements
Structural design must follow building codes used in the
country. Structural materials must
have the specification required by code. Building codes are
different from country to
country. There are many building codes, such as: International
building code (IBC),
uniform building code (UBC), Indian code, and Egyptian code, for
example. In addition,
some country has several codes. For instance, the United States
used to have several codes:
UBC in the west, BOCA on the east coast, and Southern Building
Code in southern states.
Furthermore, some countries are using the others code; like in
Saudi Arabia the current 35
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36
official used code is the International Building Code IBC 03.
Building codes may be
adapted with variations depending on weather condition, land
topography, and other special
conditions in seismic and hurricane zones. Building codes are
updated about every three
years, based on new research and conditions.
3.4.22. Site Condition (Access and Storage)
One constraint to select structural system and material is the
site condition. The site
conditions include the access to the site, storages area, site
location, and the site topography.
For example, if the site access is small or limited, that will
limit the type of equipment and
trucks that can reach the site. A site with large storage area
could use cast in place concrete,
while prefab systems are better for tight sites. Also, site
location is important to minimize
transportation distance and costs. For instance, for a project
in Los Angeles downtown with
traffic jams, the contractor should get authorization to
determine a convenient time for
material delivery.
3.4.23. Technology Availability
More and more, the field of architecture and structure has new
developments and
technologies. Further, technology of structural systems and
material may be available in one
country but not in other one. Hence, the selected system and
material should be available
locally. For example, some countries have no steel production
but produce concrete for
export In this case; use of the local material will minimize
cost and avoid transportation
costs. Technology includes equipment and tools. For instance,
crane height available may
control the maximum height of a building.
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3.4.24. Energy Efficiency and Thermal Mass
The performance of structural material can be determined and
measured by the energy
efficiency of the selected material. Each material has its own
heat properties, like heat
absorption, transmission, and reflection. For example, concrete
reduces temperature changes
in summer and winter season as well as adobe and stone
structures do (PCA & CRSI p11).
In addition, concrete releasing and absorbing heat causes
reduction of energy consumption
three ways:
First, concrete requires less energy to maintain constant
interior temperature which saves the
monthly bill. Second, concrete has greater time lag between
cooling load and peak heating
which delays heat transmission, consequently will reduce the
monthly bill (PCA & CRSI
p11). Finally, concrete reduces initial building cost by using
small cooling and heating
equipment because the concrete thermal mass lowers the cooling
and heating loads as can be
seen in figure 3.13 the difference of heat gain between the
concrete slab and steel metal deck
through 24 hours (PCA & CRSI p11).
Figure 3.13: Thermal reservoir comparisons (PCA & CRSI
p11)
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3.4.25. Soil Class
There is a strong correlation between soil and building
foundation Selection and design of
building foundation should be done after analyzing and examining
the soil. There are six
types of soil in table 3.2: soft clay, stiff clay, sand
compacted, gravel, sedimentary rock, and
hard rock (granite). Each type has a different capacity as shown
in the table, ranging from 2
ksf (100 kPa) for soft clay to 200 ksf (9600 kPa) for the hard
rock soil.
Table 3.2: Soil types and capacity (IBC table 1615.1.1,
excerpts)
For example, if the soil is poor, it should be replaced with
other type of soil or should be
excavated to a strong layer of soil. However, rock type soil can
be build on and need no
excavation. On the other hand, some soft soils may require piles
extending to stiffer layers
as shown in figure 3.13.
Figure 3.14: End bearing piles (Schierle, foundation lecture,
2006)
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3.4.26. Healthy Living & Indoor Air Quality
Indoor air quality affects healthy life, and requires
appropriate specifications of material.
Sick buildings are building with materials which produce gases
or other organic material
(PCA & CRSI p9). Each material has its own percentage of
pollution, but concrete has the
lowest interior environment impact compared to other finish
materials. Furthermore,
concrete does not require fire proofing or other coating
material which causes indoor air
pollution (PCA & CRSI p9).
3.4.27. Morphology
Correlation and integration of structure system with the
building function should be a major
objective. Each type of building has compatible structure
systems and may not be
compatible with others. For example, for office buildings,
moment frame or braced frame
systems provide flexible space for rental purpose; while
apartments and hotels require party
walls for sound insulation and privacy that can also be used as
shear walls and for fire
insulation. For exhibit halls and showrooms it is best to use
large span structures to provide
flexible space with few columns to avoid blocking of views. By
contrast, apartments and
hotels need no long span and may have short span to minimize
structure depth and cost and
provide better stiffness. Structures should also correlate with
the architectural morphology.
For example, trusses limit the size of ducts to pass through
them while Vierendeel girders
allow larger ducts (Fig. 3.14).
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Figure 3.15: Truss (a) vs. Vierendeel (b) duct constraints
3.4.28. Weather & Climate Conditions
Weather conditions obviously will affect the selection of
structural material. For example, in
hot weather area like Saudi Arabia using of wood would not be
recommended as much as
using of concrete or steel , since wood is not available. In
addition, the weather conditions
include strong winds and snow. For instance, in high wind speed
areas it is better to use
heavyweight material or braced frame system or shear walls in
order to prevent uplift and
minimize the lateral drift caused by wind force. Hence, climate
will affect the selection of
structural system and material as well. In snow area it is
better to use the sloped roofs to
minimize snow load. To design for snow load will be necessary in
order to prevent roof
collapse.
3.4.29. Security
According to current world events most buildings are designed to
protect occupants from
external dangers. There are several methods to provide security
for buildings. One of them is
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to select the safest structural material. Concrete is highly
recommended in a valuable
building that requires a high level of security like data
processing centers, hospitals, military
constructions, and nuclear facilities (CRSI p17 1997).
3.4.30. Exterior Cladding
Structural systems and materials should also be integrated with
the exterior cladding.
Several types of exterior cladding are available: precast
concrete, cast in place concrete,
masonry, glass, metal, stone, aluminum sheets, and marble. Cast
in place concrete is one of
the best but most costly systems because it can act as exterior
cladding and structural frame
as well. Furthermore, no need for connection between the
structural element and the
architectural concrete walls. The exterior cladding system
should be known in the first
structural stages in order to calculate their loads (CRSI, 1997,
p. 17).
3.4.31. Minimal Story Height
Structural systems and materials should reduce story height as
much as possible in order to
reduce the total cost as well. However, high stories are
preferred for luxury housing.
Concrete structures require less story height than the other
systems because flat plate floor
slab does not require a structural beam at all which helps to
pass the service lines under the
slab. Reducing the exterior cladding height will minimize cost.
In addition, reducing height
will reduce costs for plumbing, electrical, and HAVC.
Furthermore, decreasing floor height
obviously will reduces building volume and then reduce HAVC
consumption (CRSI p22
1997).
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3.4.32. Cash Flow and Financing Costs
Structural systems and materials should be adapted to the owner
demands and his ability to
pay. For example, cost is different for cast in place and
precast concrete. Steel fabrication
requires pre-financing and long time of order, while concrete
requires less time and less
costs. Hence, concrete can save owner money, keeping money in
the bank until the material
is ready. In addition, concrete can be provided in shorter time
which will help to finish the
construction on time in comparison to steel which requires
pre-order (CRSI p37 1997). For
example, the Wall Street journal project costs $175 million for
construction and the delay to
finish this project cost $9 million per month ($3 million in
interest and $6 million in lost
rent) for about $300,000 a day (CRSI, 1997, p37).
3.4.33. Building Configuration
Since the structure system is defined by the form of the
building, there is a strong correlation
between structure system and building shape. The shape of
building could be the shape of
plan or elevation. A complex shape will cost more than a simple
shape, and may require a
specific material, labor skills, and technology.
3.4.34. Future Modification
Structural system should provide flexibility to allow future
changes. Windows, doors, plan
layout, etc. may change in the future and require the structure
to allow such changes.
Concrete floor slab like flat slab as well as flat plate slab
are adoptive to this requirements
(CRSI, 1997, p25).
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Chapter 4 Background
4.1. Introduction
This chapter describes the wind force effects on buildings and
lateral force resisting systems.
In addition, it includes information about lateral drift in tall
buildings as well as a previous
study about lateral drift.
4.2. Wind Force
Wind consists of blowing air as shown in figure 4.1. Air has
mass and density that has
specific speed and blowing in specific direction. The energy of
wind can be calculated
according to the following equation: E = 0.5mv (Ambrose &
Vergun, 1995, p7).
Figure 4.1: Wind flow around a tall building (J. Holmes wind,
2001, p186)
4.2.1. Wind Situations
The initial stage of building design should take in account wind
speed, based on ground
level wind. The wind situation according to figure 4.2 is
considered: mild breeze 10 mph,
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stiff breeze 30 mph, windstorm periphery 50 mph, hurricanes 90
mph, violent hurricane 150
mph, and tornado up to 250 mph. (Ambrose & Vergun, 1987,
p36).
4.2.2. Correlation of Wind Speed and Pressure
Wind forces affect the building through the air pressure that
causes shear force on the
opposite direction. There is a strong correlation between wind
speed, air pressure and shear
force. When wind speed increased the pressure on the vertical
surfaces will increase as well
as the shear force. Figure 4.2 shows the relationship between
wind speeds at left which
ranges from (0 to 250 mph) and at right wind conditions which
vary from mild breeze to
tornado. The curved line visualizes the equation to calculate
the equivalent static pressure on
buildings in relation to wind speed. (Ambrose & Vergun,
1995, p8)
Figure 4.2: Relation of wind velocity to pressure on a
stationary Object (Ambrose & Vergun, 1987, p37)
4.2.3. General Wind Effects
Wind has strong effects on buildings. Wind causes shear force,
lateral drift, and other
effects, as shown in figure 4.3.
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4.2.3.1. Direct Positive Pressure
Horizontal wind on a vertical building causes a force on the
surface which faces the wind
direction (Ambrose & Vergun, 1995, p9).
4.2.3.2. Aerodynamic Drag
Wind affects building surfaces parallel to wind direction as
well, as can be seen in figure
4.3. The wind affects the roof of the building in horizontal
action which generates force on
the building forward wind direction path (Ambrose & Vergun,
1987, p38).
4.2.3.3. Negative Pressure (Suction)
On the building side opposite to the air path (leeward side),
wind causes negative pressure
which is called suction. The suction acts outward on the surface
of the building (Ambrose