Reinforced Concrete Design of Tall Buildings

Contents

1 Chapter    Design Concept 

1.1  Characteristics of Reinforced Concrete.......1
1.1.1  Confined Concrete .........1
1.1.2  Ductility4
1.1.3  Hysteresis ......................5
1.1.4  Redundancy ...................6
1.1.5  Detailing ........................6
1.2  Behavior of Reinforced Concrete Elements 7
1.2.1  Tension .7
1.2.2  Compression ..................7
1.2.3  Bending 8
1.2.3.1  Thumb Rules for Beam Design ...8
1.2.4  Shear ... 14
1.2.5  Sliding Shear (Shear Friction) ...... 18
1.2.6  Punching Shear ........... 21
1.2.7  Torsion 22
1.2.7.1  Elemental Torsion .........22
1.2.7.2  Overall Building Torsion ...........25
1.3  External Loads 26
1.3.1  Earthquakes Loads ......26
1.3.2  Wind Loads .................27
1.3.2.1  Extreme Wind Conditions .........29
1.3.3  Explosion Effects ......... 31
1.3.4  Floods .32
1.3.5  Vehicle Impact Loads ..32
1.4  Lateral Load-Resisting Systems ................32
1.4.1  Shear Walls ..................33
1.4.2  Coupled Shear Walls ...36
1.4.3  Moment-Resistant Frames ............37
1.4.4  Dual Systems ...............38
1.4.5  Diaphragm ...................38
1.4.6  Strength and Serviceability ..........39
1.4.7  Self-Straining Forces ...40
1.4.8  Abnormal Loads ..........40viii  Contents
1.5  Collapse Patterns ......................40
1.5.1  Earthquake Collapse Patterns ...... 41
1.5.1.1  Unintended Addition of Stiffness .... 41
1.5.1.2  Inadequate Beam Column Joint Strength .42
1.5.1.3  Tension/Compression Failures ...42
1.5.1.4  Wall-to-Roof Interconnection Failure .......43
1.5.1.5  Local Column Failure ...43
1.5.1.6  Heavy Floor Collapse ...44
1.5.1.7  Torsion Effects ..............44
1.5.1.8  Soft First-Story Collapse ...........45
1.5.1.9  Midstory Collapse .........45
1.5.1.10  Pounding ......45
1.5.1.11  P- Δ  Effect .....45
1.5.2  Collapse due to Wind Storms .......47
1.5.3  Explosion Effects .........47
1.5.4  Progressive Collapse ...47
1.5.4.1  Design Alternatives for Reducing Progressive Collapse .......49
1.5.4.2  Guidelines for Achieving Structural Integrity ....................49
1.5.5  Blast Protection of Buildings: The New SEI Standard ......................50
1.6  Buckling of a Tall Building under Its Own Weight 50
1.6.1  Circular Building ......... 51
1.6.1.1  Building Characteristics ............52
1.6.2  Rectangular Building .. 53
1.6.2.1  Building Characteristics ............ 53
1.6.3  Comments on Stability Analysis .. 53

2 Chapter    Gravity Systems

2.1  Formwork Considerations ........55
2.1.1  Design Repetition ........58
2.1.2  Dimensional Standards ................58
2.1.3  Dimensional Consistency .............59
2.1.4  Horizontal Design Techniques .....60
2.1.5  Vertical Design Strategy ..............63
2.2  Floor Systems ..65
2.2.1  Flat Plates ....................65
2.2.2  Flat Slabs .....................65
2.2.2.1  Column Capitals and Drop Panels ...66
2.2.2.2  Comments on Two-Way Slab Systems ......67
2.2.3  Waffl e Systems ............67
2.2.4  One-Way Concrete Ribbed Slabs .67
2.2.5  Skip Joist System .........67
2.2.6  Band Beam System .....68
2.2.7  Haunch Girder and Joist System ..70
2.2.8  Beam and Slab System 73
2.3  Design Methods ........................73
2.3.1  One-Way and Two-Way Slab Subassemblies ..73
2.3.2  Direct Design Method for Two-Way Systems . 74
2.3.3  Equivalent Frame Method ............ 75Contents  ix
2.3.4  Yield-Line Method ......77
2.3.4.1  Design Example: One-Way Simply Supported Slab ...........78
2.3.4.2  Yield-Line  Analysis of a Simply Supported Square Slab .. 81
2.3.4.3  Skewed Yield Lines ......82
2.3.4.4  Limitations of Yield-Line Method ...83
2.3.5  Deep Beams ................83
2.3.6  Strut-and-Tie Method ..85
2.4  One-Way Slab, T-Beams, and Two-Way Slabs: Hand Calculations ................92
2.4.1  One-Way Slab; Analysis by ACI 318-05 Provisions .92
2.4.2  T-Beam Design ............97
2.4.2.1  Design for Flexure ........97
2.4.2.2  Design for Shear .........100
2.4.3  Two-Way Slabs .......... 103
2.4.3.1  Two-Way Slab Design Example .....106
2.5  Prestressed Concrete Systems  108
2.5.1  Prestressing Methods  111
2.5.2  Materials .................... 111
2.5.2.1  Posttensioning Steel .... 111
2.5.2.2  Concrete ..... 112
2.5.3  PT Design .................. 113
2.5.3.1  Gravity Systems .......... 113
2.5.3.2  Design Thumb Rules .. 115
2.5.3.3  Building Examples ..... 118
2.5.4  Cracking Problems in Posttensioned Floors .120
2.5.5  Cutting of Prestressed Tendons .. 121
2.5.6  Concept of Secondary Moments 123
2.5.6.1  Secondary Moment Design Examples .....124
2.5.7  Strength Design for Flexure ....... 133
2.5.7.1  Strength Design Examples .......134
2.5.8  Economics of Posttensioning ..... 142
2.5.9  Posttensioned Floor Systems in High-Rise Buildings ..................... 143
2.5.9.1  Transfer Girder Example ......... 144
2.5.10  Preliminary Design of PT Floor Systems; Hand Calculations ........ 146
2.5.10.1  Preview ...... 146
2.5.10.2  Simple Span Beam ...... 149
2.5.10.3  Continuous Spans ....... 152
2.5.11  Typical Posttensioning Details ... 172
2.6  Foundations ... 172
2.6.1  Pile Foundations ........ 178
2.6.2  Mat Foundations ........ 179
2.6.2.1  General Considerations ............ 179
2.6.2.2  Analysis ..... 182
2.6.2.3  Mat for a 25-Story Building .... 183
2.6.2.4  Mat for an 85-Story Building .. 185
2.7  Guidelines for Thinking on Your Feet .... 187
2.8  Unit Quantities ........................ 187
2.8.1  Unit Quantity of Reinforcement in Columns  188
2.8.2  Unit Quantity of Reinforcement and Concrete in Floor Framing Systems .......197

3 Chapter    Lateral Load-Resisting Systems 

3.1  Flat Slab-Frame System ......... 201
3.2  Flat Slab-Frame with Shear Walls ...........203
3.3  Coupled Shear Walls ..............204
3.4  Rigid Frame ...205
3.4.1  Defl ection Characteristics ..........207
3.4.1.1  Cantilever Bending Component .....207
3.4.1.2  Shear Racking Component ......207
3.5  Tube System with Widely Spaced Columns ......... 210
3.6  Rigid Frame with Haunch Girders .......... 210
3.7  Core-Supported Structures ..... 212
3.8  Shear Wall–Frame Interaction ................ 212
3.8.1  Behavior .................... 217
3.8.2  Building Examples .... 218
3.9  Frame Tube System ................224
3.9.1  Behavior ....................225
3.9.2  Shear Lag...................225
3.9.3  Irregular Tube ............229
3.10  Exterior Diagonal Tube ..........230
3.10.1  Example of Exterior Diagonal Tube: Onterie Center, Chicago ........ 231
3.11  Bundled Tube .232
3.11.1  Example of Bundled Tube: One Magnifi cent Mile, Chicago ...........232
3.12  Spinal Wall Systems ...............234
3.13  Outrigger and Belt Wall System ..............234
3.13.1  Defl ection Calculations ..............238
3.13.1.1  Case 1: Outrigger Wall at the Top .238
3.13.1.2  Case 2: Outrigger Wall at Quarter Height from the Top .......239
3.13.1.3  Case 3: Outrigger Wall at Midheight ....... 241
3.13.1.4  Case 4: Outrigger Wall at Quarter Height from the Bottom . 241
3.13.2  Optimum Location of a Single Outrigger Wall .......242
3.13.3  Optimum Locations of Two Outrigger Walls 247
3.13.4  Recommendations for Optimum Locations ..250
3.14  Miscellaneous Systems ........... 251

4  Chapter  Wind Loads 

4.1  Design Considerations ............ 253
4.2  Natural Wind .255
4.2.1  Types of Wind ...........256
4.3  Characteristics of Wind ..........256
4.3.1  Variation of Wind Velocity with Height (Velocity Profi le) ..............257
4.3.2  Wind Turbulence .......258
4.3.3  Probabilistic Approach ...............260
4.3.4  Vortex Shedding ........ 261
4.3.5  Dynamic Nature of Wind ...........264
4.3.6  Pressures and Suctions on Exterior Surfaces 264
4.3.6.1  Scaling .......264
4.3.6.2  Internal Pressures and Differential Pressures ..................265
4.3.6.3  Distribution of Pressures and Suctions ....265
4.3.6.4  Local Cladding Loads and Overall Design Loads ...........266Contents  xi
4.4  ASCE 7-05: Wind Load Provisions .........267
4.4.1  Analytical Procedure—Method 2, Overview .........273
4.4.2  Method 2: Step-by-Step Procedure ......... 274
4.4.2.1  Wind Speedup over Hills and Escarpments: Factor ....280
4.4.2.2  Gust Effect Factor ....... 281
4.4.2.3  Determination of Design Wind Pressures Using Graphs ........289
4.4.2.4  Along-Wind Response 292
4.4.2.5  Worksheet for Calculation of Gust Effect Factor Along-Wind Displacement and Acceleration
4.4.2.6  Comparison of Gust Effect Factor and Along-Wind Response ....299
4.4.2.7  One More Example: Design Wind Pressures for Enclosed Building, Method 2 ... 301
4.5  National Building Code of Canada (NBCC 2005): Wind Load Provisions ....304
4.5.1  Static Procedure ........304
4.5.1.1  Specified Wind Load ..304
4.5.1.2  Exposure Factor
4.5.1.3  Gust Factors,
4.5.1.4  Pressure Coefficient,
4.5.2  Dynamic Procedure ...306
4.5.2.1  Gust Effect Factor,(Dynamic Procedure)
4.5.2.2  Design Example: Calculations for Gust Effect
4.5.2.3  Wind-Induced Building Motion .... 311
4.5.2.4  Design Example .......... 312
4.5.2.5  Comparison of Along-Wind and Across-Wind Accelerations .............. 314
4.5.3  Wind Load Comparison among International Codes and Standards ............ 315
4.6  Wind-Tunnels . 315
4.6.1  Types of Wind-Tunnel Tests .......320
4.6.1.1  Rigid Pressure Model . 321
4.6.1.2  High-Frequency Base Balance and High-Frequency Force Balance (HFBB/HFFB Model)
4.6.1.3  Aeroelastic Model .......324
4.6.1.4  Multidegree-of-Freedom Aeroelastic Model ....................330
4.6.1.5  Option for Wind-Tunnel Testing .... 331
4.6.1.6  Lower Limit on Wind-Tunnel Test Results ....................... 331
4.6.2  Prediction of Acceleration and Human Comfort .... 331
4.6.3  Load Combination Factors ......... 332
4.6.4  Pedestrian Wind Studies ............ 332
4.6.5  Motion Perception: Human Response to Building Motions ............ 335
4.6.6  Structural Properties Required for Wind-Tunnel Data Analysis ............ 335
4.6.6.1  Natural Frequencies .... 336
4.6.6.2  Mode Shapes ............... 336
4.6.6.3  Mass Distribution ....... 337
4.6.6.4  Damping Ratio ............ 337
4.6.6.5  Miscellaneous Information ...... 338
4.6.6.6  Example ..... 338
4.6.7  Period Determination and Damping Values for Wind Design ......... 341

5  Chapter  Seismic Design

5.1  Building Behavior ...................349
5.1.1  Infl uence of Soil ........349
5.1.2  Damping ....................350
5.1.3  Building Motions and Defl ections ........... 352
5.1.4  Building Drift and Separation .... 352
5.2  Seismic Design Concept ......... 353
5.2.1  Structural Response .. 353
5.2.2  Load Path .................. 353
5.2.3  Response of Elements Attached to Buildings .........354
5.2.4  Adjacent Buildings ....354
5.2.5  Irregular Buildings .... 355
5.2.6  Lateral Force–Resisting Systems ............ 356
5.2.7  Diaphragms ............... 357
5.2.8  Ductility..................... 358
5.2.9  Damage Control Features ...........360
5.2.10  Continuous Load Path ................ 361
5.2.11  Redundancy ............... 361
5.2.12  Confi guration .............362
5.2.13  Dynamic Analysis .....364
5.2.13.1  Response-Spectrum Method...367
5.2.13.2  Response-Spectrum Concept .. 371
5.2.13.3  Deformation Response Spectrum . 372
5.2.13.4  Pseudo-Velocity Response Spectrum ..... 373
5.2.13.5  Pseudo-Acceleration Response Spectrum ....................... 374
5.2.13.6  Tripartite Response Spectrum: Combined Displacement–Velocity–Acceleration (DVA) Spectrum ... 374
5.2.13.7  Characteristics of Response Spectrum ... 379
5.3  An Overview of 2006 IBC ..... 381
5.3.1  Occupancy Category . 381
5.3.2  Overturning, Uplifting, and Sliding ........383
5.3.3  Seismic Detailing ......383
5.3.4  Live-Load Reduction in Garages ............384
5.3.5  Torsional Forces ........384
5.3.6  Partition Loads ..........384
5.4  ASCE 7-05 Seismic Provisions: An Overview.....384
5.5   An Overview of Chapter 11 of ASCE 7-05, Seismic Design Criteria ...........386
5.5.1  Seismic Ground-Motion Values .386
5.5.1.1  Site Coefficients
5.5.1.2  Site Class ....389
5.5.1.3  Design Response Spectrum ......389
5.5.2  Equivalent Lateral Force Procedure ........390
5.5.2.1  Parameters S
5.5.2.2  Site-Specifi Ground Motion Analysis .....397
5.5.3  Importance Factor and Occupancy Category 398
5.5.3.1  Importance Factor
5.5.3.2  Occupancy Categories .399
5.5.4  Seismic Design Category ...........400
5.5.5  Design Requirements for SDC A Buildings .401
5.5.6  Geologic Hazards and Geotechnical Investigation .404Contents  xiii
5.5.7  Base Shear for Preliminary Design .........405
5.5.8  Design Response Spectrum for Selected Cities in the U.S.A. ......... 414
5.6  An Overview of Chapter 12 of ASCE 7-05, Seismic Design Requirements for Building Structures .....427
5.6.1  Seismic Design Basis 427
5.6.2  Structural System Selection .......427
5.6.3  Diaphragms ...............429
5.6.3.1  Irregularities ...............430
5.6.4  Seismic Load Effects and Combinations 430
5.6.5  Direction of Loading . 431
5.6.6  Analysis Procedure ... 432
5.6.7  Modeling Criteria ...... 432
5.6.8  Modal Analysis ......... 433
5.6.9  Diaphragms, Chords, and Collectors ...... 433
5.6.10  Structural Walls and Their Anchorage ...434
5.6.11  Drift and Deformation ................ 435
5.6.12  Foundation Design .... 436
5.6.12.1  Foundation Requirements for Structures Assigned to Seismic Design Category C . 437
5.6.12.2  Foundation Requirements for Structures Assigned to Seismic Design Categories
5.7  ASCE 7-05, Seismic Design: An In-Depth Discussion ........ 438
5.7.1  Seismic Design Basis  439
5.7.2  Structural System Selection .......440
5.7.2.1  Bearing Wall System ..440
5.7.2.2  Building Frame System ........... 441
5.7.2.3  Moment Frame System ............ 441
5.7.2.4  Dual System ................ 441
5.7.3  Special Reinforced Concrete Shear Wall 442
5.7.4  Detailing Requirements .............442
5.7.5  Building Irregularities ................443
5.7.5.1  Plan or Horizontal Irregularity 446
5.7.5.2  Vertical Irregularity ....448
5.7.6  Redundancy ...............448
5.7.7  Seismic Load Combinations .......449
5.7.7.1  Seismic Load Effect ....450
5.7.7.2  Seismic Load Effect with Overstrength .. 451
5.7.7.3  Elements Supporting Discontinuous Walls or Frames .......... 451
5.7.8  Direction of Loading . 451
5.7.9  Analysis Procedures .. 452
5.7.9.1  Equivalent Lateral-Force Procedure ........ 455
5.7.9.2  Modal Response Spectrum Analysis .......463
5.7.10  Diaphragms, Chords, and Collectors ......464
5.7.10.1  Diaphragms for SDC A ...........465
5.7.10.2  Diaphragms for SDCs B through F .........465
5.7.10.3  General Procedure for Diaphragm Design .......................465
5.7.11  Catalog of Seismic Design Requirements ..... 473
5.7.11.1  Buildings in SDC A .... 473
5.7.11.2  Buildings in SDC B .... 474xiv  Contents
5.7.11.3  Buildings in SDC C .... 475
5.7.11.4  Buildings in SDC D .... 476
5.7.11.5  Buildings in SDC E .... 478
5.7.11.6  Buildings in SDC F ..... 478
5.8  Seismic Design Example: Dynamic Analysis Procedure (Response Spectrum Analysis) Using Hand Calculations ..... 478
5.9  Anatomy of Computer Response Spectrum Analyses (In Other Words, What Goes on in the Black Box) .............487
5.10  Dynamic Response Concept ...497
5.10.1  Difference between Static and Dynamic Analyses .500
5.10.2  Dynamic Effects due to Wind Loads ......503
5.10.3  Seismic Periods .........504
5.11  Dynamic Analysis Theory .....505
5.11.1  Single-Degree-of-Freedom Systems .......505
5.11.2  Multi-Degree-of-Freedom Systems .........508
5.11.3  Modal Superposition Method ..... 511
5.11.4  Normal Coordinates .. 511
5.11.5  Orthogonality ............ 512
5.12  Summary ....... 518

6 Chapter    Seismic Design Examples and Details 

6.1  Seismic Design Recap ............ 523
6.2  Design Techniques to Promote Ductile Behavior 526
6.3  Integrity Reinforcement ......... 529
6.4  Review of Strength Design ..... 530
6.4.1  Load Combinations ... 532
6.4.2  Earthquake Load E .... 532
6.4.2.1  Load Combination for Verifying Building Drift .............. 534
6.4.3  Capacity Reduction Factors,  φ.... 534
6.5  Intermediate Moment-Resisting Frames . 535
6.5.1  General Requirements: Frame Beams .... 535
6.5.2  Flexural and Transverse Reinforcement: Frame Beams .................. 535
6.5.3  Transverse Reinforcement: Frame Columns . 537
6.5.4  Detailing Requirements for Two-Way Slab Systems without Beams ........................ 538
6.6  Special Moment-Resisting Frames .......... 539
6.6.1  General Requirements: Frame Beams .... 539
6.6.2  Flexural Reinforcement: Frame Beams ..540
6.6.3  Transverse Reinforcement: Frame Beams .... 541
6.6.4  General Requirements: Frame Columns . 541
6.6.5  Flexural Reinforcement: Frame Columns ..... 541
6.6.6  Transverse Reinforcement: Frame Columns .544
6.6.7  Transverse Reinforcement: Joints ...........546
6.6.8  Shear Strength of Joint ...............546
6.6.9  Development of Bars in Tension 548
6.7  Shear Walls ....548
6.7.1  Minimum Web Reinforcement: Design for Shear ..548
6.7.2  Boundary Elements ...549
6.7.3  Coupling Beams ........ 550
6.8  Frame Members Not Designed to Resist Earthquake Forces ........................ 551
6.9  Diaphragms ... 552
  6.9.1  Minimum Thickness and Reinforcement .... 552
  6.9.2  Shear Strength ......... 552
  6.9.3  Boundary Elements . 553
6.10  Foundations ... 553
  6.10.1  Footings, Mats, and Piles ......... 553
  6.10.2  Grade Beams and Slabs-on-Grade ........554
  6.10.3  Piles, Piers, and Caissons .........554
6.11  Design Examples ....................554
  6.11.1   Frame Beam Example: Ordinary Reinforced Concrete Moment Frame ........ 555
  6.11.2   Frame Column Example: Ordinary Reinforced Concrete Moment Frame ........ 557
  6.11.3   Frame Beam Example: Intermediate Reinforced Concrete Moment Frame ........ 559
  6.11.4   Frame Column Example: Intermediate Reinforced Concrete Moment Frame ........ 561
  6.11.5  Shear Wall Example: Seismic Design Category A, B, or C ...........563
  6.11.6   Frame Beam Example: Special Reinforced Concrete Moment Frame ........565
  6.11.7   Frame Column Example: Special Reinforced Concrete Moment Frame ........ 570
  6.11.8   Beam–Column Joint Example: Special Reinforced Concrete Frame ....... 574
  6.11.9  Special Reinforced Concrete Shear Wall ....577
  6.11.9.1  Preliminary Size Determination  579
  6.11.9.2  Shear Design ........... 579
  6.11.9.3  Shear Friction (Sliding Shear) ...580
  6.11.9.4  Longitudinal Reinforcement  581
  6.11.9.5  Web Reinforcement  581
  6.11.9.6  Boundary Elements  583
  6.11.10  Special Reinforced Concrete Coupled Shear Walls .......................587
  6.11.10.1  Coupling Beams .....588
  6.11.10.2  Wall Piers ...............593
6.12  Typical Details ........................599
6.13  ACI 318-08 Update .................600
  6.13.1  Outline of Major Changes ........600
  6.13.2  Summary of Chapter 21, ACI 318-08 ....605
  6.13.3  Analysis and Proportioning of Structural Members ......................605
  6.13.4   Reinforcement in Special Moment Frames and Special Structural Walls .......605
  6.13.5   Mechanical Splices in Special Moment Frames and Special Structural Walls .......606
  6.13.6   Welded Splices in Special Moment Frames and Special Structural Walls .......606
  6.13.7  Ordinary Moment Frames, SDC B .......606
  6.13.8  Intermediate Moment Frames ..606
  6.13.9  Two-Way Slabs without Beams 607
  6.13.10   Flexural Members (Beams) of Special Moment Frames ...............607
  6.13.11  Transverse Reinforcement ........608
  6.13.12  Shear Strength Requirements ...609xvi  Contents
  6.13.13   Special Moment Frame Members Subjected to Bending and Axial Loads ......609
  6.13.14  Shear Strength Requirements for Columns . 611
  6.13.15  Joints of Special Moment Frames ......... 611
  6.13.16  Special Structural Walls and Coupling Beams ..... 611
  6.13.17  Shear Wall Design for Flexure and Axial Loads .. 612
  6.13.18  Boundary Elements of Special Structural Walls ... 613
  6.13.19  Coupling Beams ...... 613

7 Chapter    Seismic Rehabilitation of Existing Buildings

7.1  Code-Sponsored Design ......... 619
7.2  Alternate Design Philosophy .. 619
7.3  Code Provisions for Seismic Upgrade ..... 621
7.4  Building Deformations ...........622
7.5  Common Defi ciencies and Upgrade Methods ......623
7.5.1  Diaphragms ...............624
7.5.1.1  Cast-in-Place Concrete Diaphragms ........624
7.5.1.2  Precast Concrete Diaphragms .627
7.5.2  Shear Walls ................627
7.5.2.1  Increasing Wall Thickness ......627
7.5.2.2  Increasing Shear Strength of Wall .628
7.5.2.3  Infi lling between Columns ......628
7.5.2.4  Addition of Boundary Elements ....628
7.5.2.5  Addition of Confi nement Jackets ...629
7.5.2.6  Repair of Cracked Coupling Beams ........629
7.5.2.7  Adding New Walls ......629
7.5.2.8  Precast Concrete Shear Walls ..629
7.5.3  Infi lling of Moment Frames .......629
7.5.4  Reinforced Concrete Moment Frames ....630
7.5.5  Open Storefront ......... 631
7.5.6  Clerestory .................. 631
7.5.7  Shallow Foundations . 632
7.5.8  Rehabilitation Measures for Deep Foundations ...... 632
7.5.9  Nonstructural Elements .............. 633
7.5.9.1  Nonload-Bearing Walls ........... 633
7.5.9.2  Precast Concrete Cladding ...... 633
7.5.9.3  Stone or Masonry Veneers .......634
7.5.9.4  Building Ornamentation ..........634
7.5.9.5  Acoustical Ceiling ......634
7.6  Seismic Rehabilitation of Existing Buildings, ASCE / SEI 41-06 ..................634
7.6.1  Overview of Performance Levels ............ 641
7.6.2  Permitted Design Methods .........642
7.6.3  Systematic Rehabilitation ...........643
7.6.3.1  Determination of Seismic Ground Motions .....................644
7.6.3.2  Determination of As-Built Conditions ....644
7.6.3.3  Primary and Secondary Components ......645
7.6.3.4  Setting Up Analytical Model and Determination of Design Forces .............645
7.6.3.5  Ultimate Load Combinations: Combined Gravity and Seismic Demand .........647
7.6.3.6  Component Capacity Calculations
7.6.3.7  Capacity versus Demand Comparisons ...649
7.6.3.8  Development of Seismic Strengthening Strategies ........... 651
7.6.4  ASCE / SEI 41-06: Design Example ......... 661
7.6.4.1   Dual System: Moment Frames and Shear Walls .............. 661
7.6.5  Summary of ASCE / SEI 41-06 ...666
7.7  Fiber-Reinforced Polymer Systems for Strengthening of Concrete Buildings ........667
7.7.1  Mechanical Properties and Behavior ......667
7.7.2  Design Philosophy .....668
7.7.3  Flexural Design .........668
7.8  Seismic Strengthening Details ................668
7.8.1  Common Strategies for Seismic Strengthening ......669

8 Chapter    Tall Buildings 

8.1  Historical Background ............688
8.2  Review of High-Rise Architecture ..........692
8.3  Functional Requirements ........694
8.4  Defi nition of Tall Buildings ....695
8.5  Lateral Load Design Philosophy .............695
8.6  Concept of Premium for Height ..............696
8.7  Relative Structural Cost ..........697
8.8  Factors for Reduction in the Weight of Structural Frame ....697
8.9  Development of High-Rise Architecture .699
  8.9.1  Architect–Engineer Collaboration ........704
  8.9.2  Sky Scraper Pluralism ..............704
  8.9.3  Structural Size .........705
8.10  Structural Scheme Options .....705
  8.10.1  Space Effi ciency of High-Rise Building Columns  716
  8.10.2  Structural Cost and Plan Density Comparison ..... 717
8.11  Summary of Building Technology .......... 718
8.12  Structural Concepts ................ 719
8.13  Bending and Shear Rigidity Index ..........720
8.14  Case Studies...724
  8.14.1  Empire State Building, New York, City, New York .......................724
  8.14.2  South Walker Tower, Chicago, Illinois .724
  8.14.3  Miglin-Beitler Tower, Chicago, Illinois 726
  8.14.4  Trump Tower, Chicago, Illinois ............730
  8.14.4.1  Vital Statistics .......... 731
  8.14.5  Jin Mao Tower, Shanghai, China .......... 731
  8.14.6  Petronas Towers, Malaysia .......734
  8.14.7  Central Plaza, Hong Kong ........736
  8.14.8  Singapore Treasury Building ... 739
  8.14.9  City Spire, New York City ........ 740
  8.14.10  NCNB Tower, North Carolina .. 740
  8.14.11  Museum Tower, Los Angeles, California .... 743
  8.14.12  MGM City Center, Vdara Tower, Las Vegas, Nevada ....................744
  8.14.13  Citybank Plaza, Hong Kong ..... 746
  8.14.14  Trump Tower, New York .......... 746xviii  Contents
  8.14.15  Two Prudential Plaza, Chicago, Illinois  747
  8.14.16  Cent Trust Tower, Miami, Florida ......... 749
  8.14.17  Metropolitan Tower, New York City ..... 751
  8.14.18  Carnegie Hall Tower, New York City ... 752
  8.14.19  Hopewell Center, Hong Kong .. 753
  8.14.20  Cobalt Condominiums, Minneapolis, Minnesota . 754
  8.14.21  The Cosmopolitan Resort & Casino, Las Vegas, Nevada .............. 757
  8.14.22  Elysian Hotel and Private Residences, Chicago, Illinois ............... 759
  8.14.22.1  Foundations ............ 759
  8.14.22.2  Floor Systems .........760
  8.14.22.3  Gravity System ....... 761
  8.14.22.4  Lateral System ....... 761
  8.14.22.5  Tuned Liquid Damper ......... 761
  8.14.23   Shangri-La New York (610 Lexington Avenue), New York ................. 762
  8.14.24   Millennium Tower, 301 Mission Street, San Francisco, California ......... 768
  8.14.25  Al Bateen Towers, Dubai, UAE ............773
  8.14.25.1  Wind Loads ............777
  8.14.25.2  Seismic Loads ........778
  8.14.26  SRZ Tower, Dubai, UAE ..........778
  8.14.26.1  Wind Loads ............779
  8.14.26.2  Seismic Loads ........ 782
  8.14.26.3  Computer Model .... 782
  8.14.26.4  Building Behavior .. 783
  8.14.26.5  Wind ...... 783
  8.14.27  The Four Seasons Hotel and Tower, Miami, Florida ..................... 783
  8.14.28  Burj Dubai ...............786
8.15  Future of Tall Buildings ......... 791

9 Chapter    Special Topics

9.1  Damping Devices for Reducing Motion Perception ....793
9.1.1  Passive Viscoelastic Dampers ......793
9.1.2  Tuned Mass Damper ...795
9.1.2.1  Citicorp Tower, New York ........796
9.1.2.2  John Hancock Tower, Boston, Massachusetts ...................798
9.1.2.3  Design Considerations for TMD ....799
9.1.3  Sloshing Water Damper ...............799
9.1.4  Tuned Liquid Column Damper ....799
9.1.4.1  Wall Center, Vancouver, British Columbia ........................800
9.1.4.2  Highcliff Apartment Building, Hong Kong .......................800
9.1.5  Simple Pendulum Damper ...........800
9.1.5.1  Taipei Financial Center 802
9.1.6  Nested Pendulum Damper ...........803
9.2  Seismic Isolation ......................804
9.2.1  Salient Features ..........806
9.2.2  Mechanical Properties of Seismic Isolation Systems ........................808
9.2.3  Elastomeric Isolators ..808
9.2.4  Sliding Isolators .......... 810
9.2.5  Seismically Isolated Structures: ASCE 7-05 Design Provisions ....... 810
9.2.5.1  Equivalent Lateral Force Procedure ......... 813
9.2.5.2  Lateral Displacements . 813
9.2.5.3  Minimum Lateral Forces for the Design of Isolation System and Structural Elements at or below Isolation System .......... 816
9.2.5.4  Minimum Lateral Forces for the Design of Structural Elements above Isolation System .. 816
9.2.5.5  Drift Limits . 817
9.2.5.6  Illustrative Example: Static Procedure ..... 817
9.3  Passive Energy Dissipation ......829
9.4  Preliminary Analysis Techniques ..............830
  9.4.1  Portal Method ........... 833
  9.4.2  Cantilever Method ....834
  9.4.3  Lateral Stiffness of Frames ........837
  9.4.4  Framed Tube Structures .............845
9.5  Torsion ...846
  9.5.1  Preview......................846
  9.5.2  Concept of Warping Behavior ...857
  9.5.3  Sectorial Coordinate  ω¢ ............. 861
  9.5.4  Shear Center ..............863
9.5.4.1  Evaluation of Product Integrals 865
  9.5.5  Principal Sectorial Coordinate Diagram..865
9.5.5.1  Sectorial Moment of Inertia
  9.5.6  Torsion Constant J ....865
  9.5.7  Calculation of Sectorial Properties: Worked Example ....................866
  9.5.8  General Theory of Warping Torsion .......867
9.5.8.1  Warping Torsion Equations for Shear Wall Structures ......870
  9.5.9  Torsion Analysis of Shear Wall Building: Worked Example........... 871
  9.5.10  Warping Torsion Constants for Open Sections ....... 881
  9.5.11  Stiffness Method Using Warping-Column Model ..883
9.6  Performance-Based Design ......885
  9.6.1  Design Ideology ........885
  9.6.2  Performance-Based Engineering ............886
  9.6.3  Linear Response History Procedure .......887
  9.6.4  Nonlinear Response History Procedure .887
  9.6.5  Member Strength ......888
  9.6.6  Design Review ..........888
  9.6.7  New Building Forms .889
9.7  Wind Defl ections ......................890
9.8  2009 International Building Code (2009 IBC) Updates .........892
  9.8.1  An Overview of Structural Revisions .....892
9.8.1.1  Earthquake Loads ........892
9.8.1.2  Wind Loads .892
9.8.1.3  Structural Integrity ......893
9.8.1.4  Other Updates in Chapter 16 ....893
9.8.1.5  Chapter 18: Soils and Foundations .893
9.8.1.6  Chapter 19: Concrete ...893
  9.8.2  Detail Discussion of Structural Revisions ....893
9.8.2.1  Section 1604.8.2: Walls ............893
9.8.2.2  Section 1604.8.3: Decks ...........894
9.8.2.3  Section 1605.1.1: Stability .......894
9.8.2.4  Sections 1607.3 and 1607.4: Uniformly Distributed Live Loads and Concentrated Live Loads
9.8.2.5  Section 1607.7.3: Vehicle Barrier Systems .......................894
9.8.2.6  Section 1607.9.1.1: One-Way Slabs ........894
9.8.2.7   Section 1609.1.1.2: Wind Tunnel Test Limitations ...........894
9.8.2.8  Section 1613.7: ASCE 7-05, Section 11.7.5: Anchorage of Walls .....897
9.8.2.9  Section 1607.11.2.2: Special Purpose Roofs ....................897
9.8.2.10  Section 1613: Earthquake Loads ...897
9.8.2.11   Minimum Distance for Building Separation .....................898
9.8.2.12  Section 1613.6.7: Minimum Distance for Building Separation ..899
9.8.2.13  Section 1614: Structural Integrity ..899
9.8.3  Chapter 17: Structural Tests and Special Inspections ........................900
9.8.3.1  Section 1704.1: General ...........900
9.8.3.2  Section 1704.4: Concrete Construction....900
9.8.3.3  Section 1704.10: Helical Pile Foundations .......................900
9.8.3.4  Section 1706: Special Inspections for Wind Requirements ..............900
9.8.4  Chapter 18: Soils and Foundations ...........900
9.8.4.1  Section 1803: Geotechnical Investigations .......................900
9.8.4.2  Section 1807.2.3: Safety Factor 900
9.8.4.3  Section 1808.3.1: Seismic Overturning ...901
9.8.4.4   Sections 1810.3.1.5 and 1810.3.5.3.3: Helical Piles ...........901
9.8.5  Chapter 19: Concrete ..901
9.8.5.1  Section 1908.1: General ...........901
9.8.5.2  Section 1908.1.9: ACI 318, Section D.3.3 901
9.8.5.3  Sections 1909.6.1 and 1909.6.3: Basement Walls and Openings in Walls ......901
9.8.6  Anticipated Revisions in 2012 IBC ..........901