CE 72.32 (January 2016 Semester): Lecture 1b: Analysis and Design of Tall Buildings using Commercial FE Programs
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The document outlines the modeling, analysis, and design of tall buildings using commercial finite element programs, emphasizing essential components such as load cases (static and dynamic), seismic loads, and structural supports. It discusses various software tools and methods for structural analysis, providing insight into material properties, load combinations, and design methodologies. Additionally, it highlights the importance of ensuring public safety through accurate modeling and the use of advanced engineering techniques.
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CE 72.32 (January 2016 Semester): Lecture 1b: Analysis and Design of Tall Buildings using Commercial FE Programs
- 1. Dr. Pramin Norachan Manager, Structural Engineering Unit, AIT Consulting Affiliated Faculty, Structural Engineering, AIT CE72.32 Tall Buildings Modeling, Analysis and Design Tall Buildings using Commercial Finite Element Programs
- 2. 1. Introduction 2. Commercial Finite Element Software 3. Basic Concepts of Finite Element Software 4. Modeling, Analysis and Design of Tall Buildings 5. Sequential Construction Cases 6. Wind Loads 7. Seismic Loads 8. Piles, Spring Supports and Foundations 9. Design Presentation Outline
- 3. To introduce commercial finite element programs used for analysis and design of tall buildings. To provide an understanding of the concepts, techniques and technologies in modeling, analysis and design of RC tall buildings using FE programs. Objectives
- 5. Dr. Pramin Norachan 5 Structural Mechanics Statics Dynamics Rigid Body Deformable Body Statics (Rigid Body) Mechanics of Materials Structural Analysis Matrix Structural Analysis Continuum or Advanced Mechanics of Materials Advanced Structures Dynamics (Rigid Body) Structural Dynamics Earthquake EngineeringWind EngineeringFinite Element Commercial FE programs (SAP2000, ETABS, STAAD Pro, ANSYS, ABAQUS, etc.) Rigid Body Deformable Body UndergraduateGraduate RC,PC, Timber, and Steel Designs Adv. RC,PC, and Steel Designs
- 6. Dr. Pramin Norachan 6 STRUCTURAL ENGINEERING IS THE ART OF USING MATERIALS That Have Properties Which Can Only Be Estimated TO BUILD REAL STRUCTURES That Can Only Be Approximately Analyzed TO WITHSTAND FORCES That Are Not Accurately Known SO THAT OUR RESPONSIBILITY WITH RESPECT TO PUBLIC SAFETY IS SATISFIED. Adapted From An Unknown Author Edward L. Wilson Professor Emeritus of Structural Engineering (The original developer of CAL, SAP and ETABS series of computer programs) University of California at Berkeley Three-Dimensional Static and Dynamic Analysis of Structures A Physical Approach With Emphasis on Earthquake Engineering
- 7. Dr. Pramin Norachan 7 Tall Building 2 Story House Stadium Offshore Structure Warehouse Bridge
- 8. Dr. Pramin Norachan 8 Architectural Functional Plans Structural System Trial Sections Modeling Analysis Revise Sections Member Design Acceptable Connection Design Detailing Final Design Yes No Conceptual Design Modeling and Analysis Design and Detailing
- 9. Dr. Pramin Norachan 9
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- 12. Dr. Pramin Norachan 12 MahaNakhon Tower (314 m)Baiyoke Tower II (304 m)
- 13. Dr. Pramin Norachan 13
- 15. Dr. Pramin Norachan Dr. Pramin Norachan Researches Structural Analysis and Design ABAQUS SAP2000, ETABS, PERFORM3D, CSIbridge ANSYS STAAD Pro ADINA MIDAS DIANA ROBOT NASTRAN SASC 15
- 16. Dr. Pramin Norachan 16 Structural and Earthquake Engineering Software Computers and Structures, Inc. (CSI) www.csiamerica.com
- 17. Dr. Pramin Norachan 17
- 18. Dr. Pramin Norachan 18 Integrated software for structural analysis and design
- 19. Dr. Pramin Norachan 19 Integrated software for structural analysis and design Ferris wheel
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- 22. Dr. Pramin Norachan 22 Integrated analysis, design and drafting of building systems
- 23. Dr. Pramin Norachan 23
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- 25. Dr. Pramin Norachan 25 Integrated 3D bridge design software
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- 28. Dr. Pramin Norachan 28 Nonlinear analysis and performance assessment for 3D structures
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- 31. Dr. Pramin Norachan 31 Integrated design of flat slabs, foundation and spread footing
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- 34. Dr. Pramin Norachan 34 Design of simple and complex reinforced concrete columns
- 36. How do the FE programs work? Creating the model (Pre-process) Reporting results (Post-process) Analysis of the Structure (FEM) A, E A, E Displacements Stresses 1 2 3 36
- 37. 1) Line Elements : Truss and Beam Elements (1D, 2D, 3D) 2) Surface Elements : Plane Stress, Plane Strain, Plate and Shell Elements (2D, 3D) 3) Solid Elements (3D) 37 Element Types
- 38. Real Structures Solid Model 3D Shell-Frame 3D Frame 2D Frame There are various ways to model a real structure 2D 3D 38 Concepts of Structural Modeling
- 39. Cable Structures Line Structures Surface Structures Solid Structures - Cable Stayed - 2D/3D Trusses - 2D/3D Frames - Plate, Shell - Plane Stress 39 Structural Types
- 40. Tall Buildings Columns : Frame elements Which types of elements will we choose to model structures? Floors : Plate or Shell elements Suspension bridges Main Towers : Frame elements Decks : Frame, Plate or Shell elements Cables : cable elements (Line structures) (Surface structures) (Line structures) (Line structures) (Line or surface structures) Beams : Frame elements (Line structures) 40
- 41. Dr. Pramin Norachan 41 EXCITATION STRUCTURE RESPONSES Loads - Gravity (DL, LL) - Wind - Earthquake Vibrations Settlements Thermal Changes (Static of Dynamic) (Elastic or Inelastic) F = K × Δ Displacements Strains Stresses Stress Resultants (Internal Forces) - Axial Force - Shear - Moment (Linear or Nonlinear) DESIGN
- 42. Dr. Pramin Norachan 42 EXCITATION STRUCTURE RESPONSES (Loads) (Stiffness) F = K × Δ (Deformation) F F K K Δ Δ F K F K
- 43. Dr. Pramin Norachan Dr. Pramin Norachan Gravity Load Lateral Load Moment Shear Moment Shear F F F F F F F F 43
- 45. 45
- 46. 46 Create the structure Assign Supports Assign Material Properties and Section Assign Loads Hinge Roller 6.00
- 47. 47 Assign Supports Perform Analysis Perform Design 3.00 3.00 3.00 3.00 3.00 3.00 stress strain E, v Concrete Steel (Concrete, Steel, Others) W W W W F F F F Fix Fix Fix M(+) M(+) M(-)M(-) M(-) Draw Grid Line Define Material Properties Define Sections Draw the Structure Assign Loads 1 2 3 4 5 6 7 8 1 2,3 4 5,6 7 8
- 53. 53 Line Element Area Element Draw the Structure4
- 55. 55 Point Load Line Load Area Load Assign Loads6
- 61. 61 • Static Load Cases - Dead Load (Sequential Construction : D) - Live Load (L) - Wind Load (W) - Equivalent Static Load Cases (E) Load cases are defined by the user and used for analysis purpose only • Dynamic Load Cases - Response Spectrum Load Cases (E) - Time History Load Cases (E) Load Cases
- 66. 66 • Static Load Cases - Dead Load (Sequential Construction : D) - Live Load (L) - Wind Load (W) - Equivalent Static Load Cases (E) Load cases are defined by the user and used for analysis purpose only • Dynamic Load Cases - Response Spectrum Load Cases (E) - Time History Load Cases (E) Load Cases
- 67. Wind Load
- 68. Dr. Pramin Norachan 68 Severe damage to an office building caused by Hurricane Andrew (1992)
- 69. Dr. Pramin Norachan 69 Torsional Flutter of the Tacoma Narrows Bridge (1940)
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- 75. Dr. Pramin Norachan 75 Vertical variation of external wind pressure coefficient Cp with respect to plan aspect ratio L/B.
- 76. Dr. Pramin Norachan 76
- 77. • Static Load Cases - Dead Load (Sequential Construction : D) - Live Load (L) - Wind Load (W) - Equivalent Static Load Cases (E) Load cases are defined by the user and used for analysis purpose only • Dynamic Load Cases - Response Spectrum Load Cases (E) - Time History Load Cases (E) 77 Load Cases
- 78. Dr. Pramin Norachan 78 Pressure loads on Surrounding areas Point loads at the center of diaphragms Wind Pressure Point loads at column nodes 1 2 3
- 79. 79 Point loads at the center of diaphragms 2
- 80. 80 Point loads at the center of diaphragms 2
- 81. 81 Pressure loads on Surrounding areas 3
- 82. 82 Pressure loads on Surrounding areas 3
- 83. 83 Pressure loads on Surrounding areas 3
- 84. 84 Pressure loads on Surrounding areas 3
- 85. Seismic Load
- 86. Dr. Pramin Norachan 86 A reinforced concrete house in Chiang Rai collapsed due to a strong earthquake event.
- 87. Dr. Pramin Norachan 87 The other wood house which is located nearby the first RC house can stand over the earthquake event. There was no structural damage which could be observed. The first reason is possible due to the light weight (mass) of the wood building, which produced the less seismic force. The second reason is due to the wood structure is very flexible, which can perform with large deformation.
- 88. Dr. Pramin Norachan 88 m 2 k u gu 2 k c (a) Moving Base m 2 k u ( ) ( )eff gp t mu t 2 k c (b) Stationary Base ( ) ( )eff gp t mu t Effective Earthquake Force, ( )effp t 0 ?m 0 ?gu
- 89. 89 Seismic Load 1) Equivalent Statics 2) Response Spectrum 3) Time History - Static approach - Simple regular structures - Low-to-medium-rise building - Dynamic approach - All structures - Suitable for structural design - Dynamic approach - All structures - The most accurate analysis - Both linear and nonlinear - Based on fundamental mode - Linear analysis - Linear analysis - Take time for analysis - Difficult to combine the results
- 90. • Static Load Cases - Dead Load (Sequential Construction : D) - Live Load (L) - Wind Load (W) - Equivalent Static Load Cases (E) Load cases are defined by the user and used for analysis purpose only • Dynamic Load Cases - Response Spectrum Load Cases (E) - Time History Load Cases (E) 90 Load Cases
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- 92. • Static Load Cases - Dead Load (Sequential Construction : D) - Live Load (L) - Wind Load (W) - Equivalent Static Load Cases (E) Load cases are defined by the user and used for analysis purpose only • Dynamic Load Cases - Response Spectrum Load Cases (E) - Time History Load Cases (E) 92 Load Cases
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- 96. • Static Load Cases - Dead Load (Sequential Construction : D) - Live Load (L) - Wind Load (W) - Equivalent Static Load Cases (E) Load cases are defined by the user and used for analysis purpose only • Dynamic Load Cases - Response Spectrum Load Cases (E) - Time History Load Cases (E) 96 Load Cases
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- 99. Piles, Spring Supports and Foundations
- 100. 100 The fist model is used for finding number of piles and preliminary designing the foundations based on loads at the supports. The model with Normal Supports
- 101. The Model with Piles The second model is included both piles and foundations. The internal forces of piles which are used to design pile detailing can be known by perform the linear analysis for this model. 101
- 102. Equivalent Spring Supports Actual pile embedded in soil 102 𝐾𝑣 = 𝐹𝑣 ∆ 𝑣 𝐾ℎ = 𝐹ℎ ∆ℎ 𝐹𝑣 𝐹ℎ ∆ 𝑣 ∆ℎ 𝐾𝑣 𝐾ℎ Soil represented by lateral spring Pile modeled with lateral spring Pile deformation under applied loads 𝐾 = 𝐾𝑠 × 𝐴ℎ 𝐾
- 103. The Model with Spring Supports This model can be used for foundation design by exporting the foundation floor to SAFE, and it will be used for analysis and design in the remaining works. 103
- 104. Design
- 105. Programs for Structural Design - Beams - Columns - Shear Walls - Arbitrary shape Columns - Composite Columns - Slabs - Post tension Slabs - Foundations
- 107. Design for Parts of the Structures Water tank Mat Foundation Floor Transfer beam Roof Structures
- 108. Swimming pool Guard house Project road Fence Design for Parts of the Structures
- 110. Dr. Pramin Norachan 110 Demand Force (D) ≤ Structural Capacity (C) u nF F 1.0u n FD C F Strength Design Method (SDM)
- 111. Dr. Pramin Norachan 111 No. Load Combinations Description 1 1.4 DL Dead load 2 1.2 DL + 1.6 LL Gravity load 3 1.2 DL + 1.0 LL + 1.6 WL Wind load (compression) 4 0.9 DL + 1.6 WL Wind load (tension) 5 1.2 DL + 1.0 LL + 1.0 EQ Seismic load (compression) 6 0.9 DL + 1.0 EQ Seismic load (tension) ACI 318-08 (Strength Design Method) : SDM Load factor on the live load LL in No. 3 and 5 shall be permitted to be reduced to 0.5 except for all areas where LL is greater than 500 kg/m2.
- 112. Dr. Pramin Norachan 112 No. Load Combinations Description 1 DL Dead load 2 DL + LL Gravity load 3 DL + 0.75 LL + 0.75 (0.6 WL) Wind load (compression) 4 0.6 DL + 0.6 WL Wind load (tension) 5 DL + 0.75 LL + 0.75 (0.7 EQ) Seismic load (compression) 6 0.6 DL + 0.7 EQ Seismic load (tension) ASCE 7-10 (Allowable Stress Design)
- 113. Dr. Pramin Norachan 113 Member Items Demand (D) Capacity (C) Design Concept Pile Number of piles Service load combinations (including footing weight) Ultimate pile load → Calculate from soil report Safe load = Ultimate load SF SF ≈ 2.0 – 2.5 RC Design Ultimate load combinations (including footing weight) D n C ( )n n n PMM F V Compression Tension 1.0u n FD C F F uF
- 114. Dr. Pramin Norachan 114 Member Items Demand (D) Capacity (C) Design Concept Footing RC design Ultimate load combinations (including footing weight) Column above footing RC design Ultimate load combinations (including footing weight) n n n M F V 1.0u n FD C F uF uF 1.0u n FD C F One-way shear Punching shear n n PMM F V Compression Tension
- 115. Dr. Pramin Norachan 115 Member Items Demand (D) Capacity (C) Design Concept Beam/ Stair RC design Ultimate load combinations Column/ Shear wall RC design Ultimate load combinations One-way slab RC design Ultimate load combinations Two-way slab RC design Ultimate load combinations n n n M F V 1.0u n FD C F uF uF 1.0u n FD C F n n PMM F V Compression Tension uF n n n M F V 1.0u n FD C F uF n n n M F V 1.0u n FD C F One-way shear Punching shear
- 116. Dr. Pramin Norachan 116 2 n s y a M A f d 0.85 ' s y c A f a f b • Flexural Design • Shear Design n c sV V V ' 0.53c cV f bd v y s A f d V s
- 117. Dr. Pramin Norachan 117
- 118. Dr. Pramin Norachan Manager, Structural Engineering Unit, AIT Consulting Affiliated Faculty, Structural Engineering, AIT Thank You