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Overview of Performance Based Design and AIT Experience
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- 2. 2 • Located 42 km from central Bangkok • 330 acre (130 Ha) green campus • Adjacent to Thammasat University & Thailand Science Park, Thailand’s National Science and Technology Development Agency (NSTDA) • Home to 2500+ faculty, staff, students from 50+ countries AIT Campus 2
- 3. 3 Asian Institute of Technology (AIT) SET SERD SOM
- 4. 4 AIT Solutions established in AIT since 2010
- 5. 5 Pls replace the text in the circle with our mission (next slide) “Building upon AIT schools, labs, research centers, and alumni resources to advance technological development of the region”
- 8. 8 Primary Focus of Research and Projects Clients, Partners, Consultants PBD Value Engineering Peer Review Structural System Development Smart Structures Wind Tunnel Studies Failure Investigations Innovative Solutions Specialized Modeling and Analyses
- 9. 9 Wind Engineering Solutions Structural dynamic wind loads & response study Structural dynamic wind loads & response study Facade pressure study
- 10. 10 100 200 300 metres PBD of 100+ Tall Buildings Gramercy Residences Stratford Residences Shang Salcedo Place Royalton Tower Discovery Primea One Shangri-la Place (Tower 1&2) Anchor Grandsuites Maven Tower 1 Knightsbridge Residences Imperium Tower Park Terraces Tower Garden Tower Shangri-la at the Fort Trump Tower
- 11. 11 11 Why this Seminar? And why are these topics important
- 12. 12 Colombo 2015 Kathmandu 2016 Bangkok 2016 Singapore 2016 Manila 2016 Oman 2017 Dubai 2017 Yangon 2015 Islamabad 2017 Wah 2017 NED 2017 Manila 2017 Hanoi 2017 Singapore 2017 Yangon 2017 MUET 2017
- 13. Structural Engineering is the Basis for Built Environment
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- 27. 27 27 A MUST read for structural Engineers
- 28. Demand and Complexity is Increasing for the Built Environment
- 29. Percentage of Urbanized World 29
- 30. World’s Population Urban-to-Rural Ratio 30 (www.un.org)
- 31. Population Growth is in Developing World 31 Source: www.prb.org, volume no. 66, July, 2011. Less Developed Countries will need more Low Cost Housing and infrastructure for nearly 2 Billon more people
- 32. Visions for the Future are for “Vertical Cities” 32 Japan, 4000m Sky Mile Tower, 1700 m JapanDubai City Tower, 2400 m One Dubai Tower, 1008 m
- 33. The Reality 33
- 34. 34 34 Source: CTBU Report, 2015
- 35. 35 35 The Twisting Turning Towers Trend Source: CTBU Report, 2015
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- 37. 37 Buildings and Structures are expected to be • Safe • Secure • Serviceable • Reliable • The contents of the structures are often much more valuable than structure itself • The loss of service/operations/business is a often larger than repair costs • Protective • Friendly • Sustainable • Affordable
- 38. 38 Key Challenges in (Tall) Buildings • Taller • Slender • Twisting • Unusual forms • Multi Use • Changing Plans • Larger column free spaces • Smaller Cores • Minimizing Floor Height • Minimize floor depth • Minimize column size • Minimize structural cost • Inclined columns • Free form • Unusual requests
- 39. 39 How does CTBUH look at Tall 39 Relatively Tall. Both for public and the professions who design and construct Proportion Slenderness, in plan and in elevations Systems and Technologies Uses something “different” than ordinary buildings
- 40. 40 40 Very Tall (1142) Super Tall (110) Mega Tall (3) Low Tall Low Rise >600 m>300 m>200 m>100 m<50 m Tall (3740) >150m Source: CTBU Report, 2015
- 41. 41 Main Structural Concerns Stability and integrity 01 Strength and Servivbility 02 Deformation 03 Drift 04 Ductility 05 Energy Dissipation 06 Motion Perception 07
- 42. 42 Building Industry relies on Codes and Standards • Codes Specify requirements • Give acceptable solutions • Prescribe (detailed) procedures, rules, limits • (Mostly based on research and experience but not always rational) Spirit of the code is to help ensure Public Safety and provide formal/legal basis for design decisions Compliance to letter of the code is indented to meet the spirit
- 43. 43 What a Structural Engineer said ! Hardy Cross, 1885-1959
- 44. 44 For most buildings, dynamic wind response may be neglected Gust factor approach predict dynamic response of buildings with reasonable accuracy Structures are designed to respond elastically under factored loads Structures are designed to respond inelastically under factored loads it is not economically feasible to design structures to respond elastically to earthquake ground motion Design for Seismic EffectsDesign for Wind Load
- 45. 45 Basic Physics of Dynamics • Newton’s View, for rigid bodies F = ma
- 46. 46 Structural engineer’s View FKuuCuM for linear elastic, deformable bodies
- 47. 47 Dynamic Equilibrium FFKuuCuM NL Damping-Velocity Mass-Acceleration Stiffness-Displacement Nonlinearity External Force KuuCuM The basic variable is displacement and its derivatives
- 48. 48 Seismic Response FFKuuCuM NL Linear Time History Analysis 0 KuuM EQNL FFKu Free Vibration Pushover Analysis EQFKu Equivalent Static Analysis EQFKu Response Spectrums Response Spectrum Analysis Acceleration Records guMKuuCuM Nonlinear Time History Analysis
- 49. 49 Typical Linear Dynamic Response of Tall Building Animation
- 50. 50 Structures are designed to respond inelastically under factored loads it is not economically feasible to design structures to respond elastically to earthquake ground motion Design for Seismic Effects
- 51. Introducing AIT Solutions 51 0 5 10 15 20 25 30 35 40 45 0 10 20 30 40 50 60 The Problem with R Factor The elastic forces obtained from the standard RSA procedure The RSA elastic forces reduced by 𝑅 The inelastic forces obtained from the NLRHA procedure The actual reduction in RSA elastic forces. The “reward” of making a nonlinear model The underestimation causing a “false sense of safety” due to directly reducing the RSA elastic forces by 𝑅 factor Story Shear (x106 N) StoryLevel • The R factor may vary from 2 to 8 depending on definition of structure type • R factor could “off” by a factor of 2 to 4 • Other names for R factor are Response Factor, Behavior Factor (q), Structure Type factor (K) etc., Fawad Najam, 2017
- 52. 52 Effect of Modes on Story Moment 52
- 53. 53 Effect of Modes on Story Shear 53
- 54. 54 The Problem with R (and other) Factors Reducing each mode with same factor can underestimate demand Each Mode undergo different level of nonlinearity Modified Modal Superposition (Priestley and Amaris, 2002) R applied to only first mode, with higher modes assumed elastic Solution (Rachut, 2013) Uncoupled modal response history analysis (UMRHA) R” factor can only accurately reduce true demand of the 1st mode
- 55. 55 Are All Buildings Codes Correct ? • All codes have different values of R and other factors • If they differ, can all of them be correct ? • Did we inform the structures to follow which code when earthquake or hurricane strikes ? • Codes change every 3 or years, should we upgrade our structures every 3 or 5 years to conform ?
- 56. 56 Code Comparison for Seismic Performance • Compare Performance of buildings designed to different codes • ACI 318-14 + ASCE 7-10 • BS 8110-1997 + EURO-8 • EURO-2-2004 + EURO-8 • For low-seismic and high seismic zone • Manila > Very High • Bangkok > Low to medium • All produce different level or performance in different components !! Two MS Thesis, 2016 at AIT
- 57. Shift From Prescriptive to Performance Based Approach
- 58. 58 Prescriptive vs. Performance Approach Procedure Outcome Prescriptive (emphasis on procedures) Specify “what, and how to do” Make Concrete: 1:2:4 Implicit Expectation (a strength of 50 MPA is expected) Performance Based Approach (emphasis on Key Performance Indicators) What ever it takes (within certain bounds) Explicit Performance Concrete less than 40 MPA is rejected
- 59. 59 Prescriptive Codes – A Shelter and an Impediment • Public: • Is my structure safe ? • Structural Engineer: • Not sure, but I did follow the “Code” As long as engineers follow the code, they can be sheltered by its provisions
- 60. 60 The “Arbitrary Factors” in Codes
- 61. 61 Capacity Based on “Assumed” Failure Conditions
- 63. 63 A Move Towards Performance-based Approach • Prescriptive Codes restrict and discourage innovation Objective Requirements Prescribed Solution Objective Requirements Alternate Solution • Performance Based approach encourages and liberates it
- 64. 64 • Lack of explicit performance in design codes is primary motivation for performance based design • Performance based methods require the designer to assess how a building is likely perform extreme events and their correct application will help to identify unsafe designs. • Enables arbitrary restrictions to be lifted and provides scope for the development of innovative, safer and more cost-effective solutions
- 65. 65 Design Approaches Intuitive Design Prescriptive Code Based Design Performance Based Design >> >>>
- 66. 66 Performance based design can be applied to any type of loads, but was initially developed and targeted for earthquake loads
- 67. 67 Typical Performance Levels Based on FEMA 451 B
- 68. 68 Typical PB Review Enhance Structural Performance Improved serviceability, safety and reliability Explicit check on various performance indicators Improve Cost Effectiveness Achieve efficient use of materials, resources and time Direct reduction cost through reduction of structural material quantities Objectives to be achieved through Better structural system selection and its proportions Use of advanced design methodologies and tools
- 69. 69 Explicit Performance Objective in PBD Performance based design investigates at least two performance objectives explicitly Service-level Assessment Ensure continuity of service for frequent hazards (Earthquake having a return period of about 50) Collapse-level Assessment Ensure Collapse prevention under extreme hazards (the largest earthquake with a return period of 2500 years) Codes arbitrary implicit “Design Level”
- 70. 70 Performance Objectives Level of Earthquake Seismic Performance Objective Frequent/Service (SLE): 50% probability of exceedance in 30 years (43-year return period) Serviceability: Structure to remain essentially elastic with minor damage to structural and non- structural elements Design Basis Earthquake (DBE): 10% probability of exceedance in 50 years (475-year return period) Code Level: Moderate structural damage; extensive repairs may be required Maximum Considered Earthquake (MCE): 2% probability of exceedance in 50 years (2475-year return period) Collapse Prevention: Extensive structural damage; repairs are required and may not be economically feasible
- 71. 71 Seismic Hazard Spectrum, SLE and MCE MCE Level Service Level
- 72. 72 Selecting and Scaling Ground Motions Best represent – the characteristics of expected event at the site Magnitude Distance Fault type Scaling Spectral matchingUniform scale factor applied Using wavelet adjustment Amplitude scaling Need fewer ground motion Frequency domain Time domain Use RSPMatch Software Unrealistic – high energy content in the lower period range Distorted displacement & velocity records of original ground motion Selecting (Kevin & Finley,2014) Spectral matched Amplitude scaled Use 7 ground motion records and scale it to MCE level for NLRHA method (Klemencic et al. , 2007) Uniform Hazard Spectrum VS Conditional Mean Spectrum
- 73. 73 Analysis Procedures Non-Linear Response History Analysis (NLRHA) Non-Linear Static Procedure (NSP) Construction Sequence Analysis Uncoupled Modal Response History Analysis (UMRHA)—Chopra and Goel (2002) Linear Response Spectrum Analysis (LRSA) Linear Response History Analysis (LRHA) NeedR
- 74. 74 Judging Performance Acceptability • Acceptance criteria are indicators of whether the predicted performance is adequate for • Local (component based) • Global (overall structure-based) • The non-linearity and inelasticity need to be realized and considered
- 75. 75 Typical Force Displacement Relationship 75
- 76. 76 Performance Based Design Process Acceptance Criteria for Primary Components
- 77. 77 Performance Based Design Process Acceptance Criteria for Secondary Components
- 78. 78 Classification of Actions Element Action Type Classification Expected Behavior RC column Axial-flexure Shear Ductile Brittle Linear Linear RC shear wall Flexure Shear Ductile Brittle Nonlinear Linear RC coupling beams (Deep beam, ln/d<4.0) Shear Ductile Nonlinear RC coupling beams (slender beam, ln/d≥4.0 Flexure Shear Ductile Brittle Nonlinear Linear
- 79. 79 MCE Acceptance 79 Acceptance Criteria for Maximum Considered Earthquake (MCE) Item Value Peak transient drift (TBI, Page 71) , (LATBSDC, Page 40) Maximum of mean values shall not exceed 3%. Maximum drift shall not exceed 4.5%. Residual drift (TBI, Page 71) , (LATBSDC, Page 40) Maximum of mean values shall not exceed 1%. Maximum drift shall not exceed 1.5%. Coupling beam inelastic rotation ≤ASCE 41-13 limits Column Inelastic Rotation ≤ASCE 41-13 limits Shear wall reinforcement axial strain ≤0.05 in tension and ≤0.02 in compression Shear wall shear Remain elastic. (Check for 1.5 times mean value) Girder inelastic rotation ≤ASCE 41-13 limits Girders shear Remain elastic. Force Structural Displacement Immediate Occupancy (IO) Life Safety (LS) Collapse Prevention (CP)
- 80. 80 Demand Capacity (DC Ratio) • Definition of D/C: It is an index that gives an overall relationship between affects of load and ability of member to resists those affects. • This is a normalized factor that means D/C ratio value of 1 indicates that the capacity (strength, deformation etc) member is just enough to fulfill the load demand. • Two types of D/C ratio Members with brittle behavior D/C is checked by Strength (Elastic) Members with ductile behavior D/C is checked by deformation (Inelastic) • Total D/C ratio of the member is combined of these two.
- 81. 81 Cost Effectiveness > Utilization Ratio • Utilization Ratio • Compare, What is Needed against What is Required • One measure • The Demand/ Capacity Ratio (D/C) Demand/ Capacity Columns No. % D/C<0.5 178 16% 0.5<D/C<0.7 534 49% 0.7<D/C<1 346 31% 1<D/C<1.5 30 3% 1.5<D/C<2.5 12 1% D/C>2.5 0 0% Total 1100 100.00% Ideal Not Cost Effective Not Safe
- 82. Special Purposes Guidelines from USA for PBD 82 Applied Technology Council (ATC) Federal Emergency Management Agency (FEMA) and National Earthquake Hazards Reduction Program (NEHRP) PEER Guidelines for Tall Buildings Tall Buildings Initiatives (TBI) CTBUH Guidelines
- 83. AIT and PBD • Research labs to support innovation • More than 100 tall building projects in Asia • Carried out for several developers and structural engineers • Many of which further reviewed by third-party experts based in the USA • More than 50 MS and PhD Thesis on PBD Tall Buildings
- 84. 84 Building Distribution of PBD Projects
- 85. 85 Tower 1 Tower 2 A Case Study For Explanation of Process • 51-story high-rise residential building • 4-story below-grade car parking • Approximately 170 m high • Post-tensioned slab column frames and bearing walls • Mat foundation system 85
- 87. 87 Overall Design Methodology 87 1 Preliminary Design (Code based design approach) (by Designer) 2 Service Level Evaluation (43-year return period) 3 Collapse Prevention Level Evaluation (2475-year return period)
- 88. 88 Seismic Performance Objectives 88 Level of Earthquake Seismic Performance Objective Frequent/Service Level Earthquake (SLE): 50% probability of exceedance in 30 years (43-year return period) Serviceability: Limited structural damage, should not affect the ability of the structure to survive future Maximum Considered Earthquake shaking even if not repaired. Maximum Considered Earthquake (MCE): 2% probability of exceedance in 50 years (2475-year return period) Collapse Prevention: Building may be on the verge of partial or total collapse, extensive structural damage; repairs are required and may not be economically feasible.
- 89. 89 Acceptance Criteria (SLE) 89 Item Limit Story drift 0.5% Link beam Remain elastic Shear wall Remain elastic Column Remain elastic • Demand to capacity of the primary structural members shall not exceed 1.5, in which the capacity is computed by nominal strength multiplied by the corresponding strength reduction factor in accordance with ACI 318. • It is anticipated that the demand to capacity ratio of 1.5 based on design strengths can be expected to result in only minor inelastic response.
- 90. 90 Acceptance Criteria (MCE) 90 Item Limit Peak transient drift Mean value shall not exceed 3%. Maximum drift shall not exceed 4.5%. Residual drift Mean value shall not exceed 1%. Maximum drift shall not exceed 1.5%. Column Remain elastic Link beam rotation Conventional Reinf. ≤ 0.04 radians Shear wall reinforcement strain ≤ 0.05 in tension ≤ 0.02 in compression Shear wall concrete strain Intermediately confined concrete ≤ 0.004 + 0.1 ρ (fy / f'c) Fully confined concrete ≤ 0.015 Force-controlled action demand shall be 1.5 times the mean if it is not limited by well defined yield mechanism. If it is limited by well-defined yield mechanism, use the mean plus 1.3 times standard deviation but not less than 1.2 times the mean. The capacity is determined based on expected material properties with corresponding strength reduction factor.
- 91. 91 Seismic Input 91 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 1 2 3 4 5 6 7 8 9 10 SPECTRALACCELERATION(g) PERIOD (sec) RESPONSE SPECTRA SLE 2.5% Damping MCE 5% Damping
- 92. 92 Ground Motion Selection Modified by adding small wavelets to the time series to finally obtain accurate spectral matching with MCE ( Munir, 2011 ) Use RspMatch software to match the records to target spectrum Use PEER NGA and COSMOS databases (PEER, 2005, COSMOS 1999-2007) to find suitable ground motion records 7 ground motion records Records scaled by a constant factor spectrum roughly match with that of MCE MCE response spectrum is assumed to be 1.5 times the 5% damped DBE response spectrum. Uniform Hazard Spectrum Vs Conditional Mean Spectrum
- 93. 93 Finite Element Model • Linear Elastic Model • Used for DBE, SLE and wind analysis • Used ETABS • All components were modeled as elastic. • Response spectrum analysis was conducted for DBE and SLE earthquakes. • Nonlinear, Inelastic Model • Used for MCE analysis • Used Perform 3D • Inelastic member properties • Flexural response of shear walls • Flexural response of coupling beams • Flexural response of slab outrigger beams • Elements that are assumed to remain elastic were modeled with elastic member properties. • Nonlinear time history analysis was conducted for seven sets of ground motions. 93
- 94. 94 Recognizing and Considering Nonlinearity 94 Advanced Concrete l Dr. Naveed Anwar
- 95. 95 Nonlinear Modelling Fig: Idealized Models of Beam-Column Elements NEHRP Seismic Design Technical Brief No.4 Consider Geometric nonlinearity (P-∆) effects
- 96. 96 NL Modeling of Shear Walls For fiber elements use adequate amount of concrete and steel fibers Each one of these fibers is assigned nonlinear material stress-strain relationship (Modeling for Structural Analysis, Behavior and Basics. Graham H. Powell)
- 97. 97 Material Models Mander’s model for concretePark’s model for steel
- 99. 99 Modal Analysis ResultsTranslationin Minor direction Translationin Major direction Torsional • T1=5.32 sec • 60% in Minor direction • T6=1.28 sec • 18% in Minor direction • T9=0.75 sec • 6.5% in Minor direction • T2=4.96 sec • 66% in Major direction • T7=0.81 sec • 5.2% in Major direction • T4=1.56 sec • 15% in Major direction T3=4.12 sec T8=0.65secT5=1.30 sec
- 100. 100 Base Shear 100 4.1% 2.9% 13.2% 8.7% 3.4% 5.4% 20.0% 14.3% 10.9% 7.0% 0% 5% 10% 15% 20% 25% X Y BaseShear% Along Direction Base Shear Percentage of Total Weight of Building Elastic SLE Elastic DBE Wind*1.6 (RWDI) Elastic MCE Inelastic MCE NLTHA
- 101. 101 Story Drift 101 0 10 20 30 40 50 -5% 0% 5% Story Transient Drift (%) Transient Drift in X-dir. at MCE Level ARC CHY DAY ERZ LCN ROS TAB Average Avg. Drift Limit Max. Drift Limit 0 10 20 30 40 50 0.0% 0.5% 1.0% 1.5% 2.0% Story Residual Drift (%) Residual Drift in X-dir. at MCE Level ARC CHY DAY ERZ LCN ROS TAB Average Avg. Drift Limit
- 102. 102 Story drifts and lateral displacements are within the acceptable limits. The building is expected to remain serviceable under frequent earthquakes. Strength demand to capacity ratios of primary structural members were less than 1.5. Performance Evaluation (SLE) 102
- 104. 104 Shear Walls Performance 104 Strain Gauge (C04) SW 1-1 -5 5 15 25 35 45 55 -0.006 -0.001 0.004 Story Axial Strain (mm/mm) Wall Axial Strain (C04) ARC CHY DAY ERZ LCN ROS TAB Average Steel Yielding Strain Strain gauge locations in shear walls
- 105. 105 Shear Walls 105 -5 5 15 25 35 45 55 -200000 -100000 0 100000 200000 Story Shear Force (KN) Shear Wall Shear Demand vs. Capacity (SW1-1) ARC CHY DAY ERZ LCN ROS TAB AVERAGE Capacity Maximum Limit Capacity SW1-1
- 106. 106 Coupling Beams 106 -10 0 10 20 30 40 50 60 -0.1 -0.05 0 0.05 Story Rotation (radians) Link Beam Rotation (LB-1) ARC CHY DAY ERZ LCN ROS TAB Average
- 107. 107 Energy Dissipation Total dissipated energy Dissipated energy from coupling beams
- 108. 108 Slab Outrigger Beams • Post-tensioned slab was designed as “nonparticipating” system (not part of the lateral load resisting system) to resist the gravity loads under the expected lateral displacements. • Checked by two methods to reduce the likelihood of punching shear failure under seismic loading. • Inelastic rotation of the slab outrigger beams was checked in accordance with ASCE 41. • Story drift with respect to gravity load punching shear D/C ratio was checked in accordance with ACI 318-08 Sect. 21.13.6.
- 109. 109 Slab Outrigger Beams 109 0 10 20 30 40 50 -0.05 0 0.05 0.1 Story Slab Beam Rotation (radians) Moment Hinge Rotation due to Positive and Negative Moment(SB2-1) ARC CHY DAY ERZ LCN ROS TAB Average Limit
- 110. 110 Core Only Config 1 Config 2 Config 3 Config 4 Config 5 Research on Partial Outrigger Options (Flag Walls)
- 111. 111 Diaphragm Transfer Forces Large diaphragm transfer forces should be anticipated at offsets or discontinuities of the vertical elements of the seismic-force- resisting system. (a) Setback in the building profile (b) Podium level at grade.
- 113. 113 Typical Diaphragm Components Chord (Diaphragm) Chord (Diaphragm) Collector (Support) Shear Friction (Support) Shear (Diaphragm) Shear Wall Diaphragm 1 2 4 3
- 114. 114 Realistic Model - Finite Element Model • Finite element modeling of a diaphragm can be useful for assessing the force transfer among vertical elements, force transfer around large openings or other irregularities. Shear WallsShear Walls Shear Walls
- 115. 115 Multi-Tower Vs Single Tower Models
- 116. 116 Modeling Options • Individual design of tower and podium separately in practice • Restraint of resources such as software, processing time, understanding and references Single tower without podium Single tower with half podium Single tower with whole podium Twin tower with whole podium
- 117. 117 Diaphragms 117 Tower diaphragm Ground level diaphragm
- 118. 118 Diaphragm Reinforcement 118 Multi Tower Scenario for in-phase and out-phase
- 119. 119 Soil Structure Interaction Modeling TBI Guidelines (Practice at AITS) Practice Research at AIT
- 121. 121 • Out-of plane flexure and shear (Lateral pressure from soil) • Inertia component • Kinematic component • In-plane shear (force transferred from ground and basement level diaphragms) Basement Walls 121
- 122. 122 How to Work with PBD 122 Requires: • Detailed modeling • Nonlinear-dynamic analysis • Appropriate computing tools, knowledge , skills and lots of patience Go Beyond Codes Sophisticated Structural Modelling Stare of Art Computer based tools
- 123. 123 Peer Review Owner Will the building be safe? Can I use the building after the hazard? How much will repair cost in case of damage? How long will it take to repair? Engineer Free to choose solutions, but ensure amount of yielding, buckling, cracking, permanent deformation, acceleration, that structure, members and materials experiences Need a third party to ensure public safety and realistic Performance Guidelines Peer Review
- 124. Going Beyond PBD
- 125. 125 Non-Structural Damage Assessment of Tall Buildings
- 126. 126 Design Approaches Intuitive Design Code Based Design Performance Based Design Consequences and Risk Based Design Resilience Based Design
- 127. 127Source: Arup, Supported by USRC and many others Green Buildings Resilient Buildings
- 128. 128 Linking Performance to other Indicators 128 Operational (O) Immediate Occupancy (IO) Life Safety (LS) Collapse Prevention (CP) 0 % Damage or Loss 99 % Ref: FEMA 451 B CasualtiesLowest Highest Rehab Cost to Restore after eventLowest Highest Retrofit Cost to Minimize ConsequencesHighest Lowest Downtime for RehabLowest Highest
- 129. 129 • A holistic approach which seeks to identify all hazard-induced risks (including those outside the building envelope) and mitigate them using integrated multi-disciplinary design and contingency planning to achieve swift recovery objectives in the aftermath of a major earthquake. • The key principle in resilience-based design is to limit expected damage to structural and architectural components and egress systems (elevators, stairs, and doors) Resilience Based Earthquake Design
- 130. 130ARUP
- 131. 131 Two Levels of Seismic Hazard is Considered • DBE or Design Basis earthquake (DBE): Defines the peak horizontal acceleration with 10% probability of exceedance in 50 years. • MCE or Maximum Considered Earthquake: Defines the peak horizontal acceleration with 2% probability of exceedance in 50 years. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 1 2 3 4 5 6 Frequent/Service-level Earthquake Spectral Acceleration (g) Maximum Considered Earthquake (MCE - 2475 Years Return Period)
- 132. 132 Structural Responses under SLE and MCE Level Seismic Hazard 0 5 10 15 20 25 30 35 40 45 50 55 0 0.002 0.004 0.006 0.008 No:ofstory drift Drift under SLE level Drift-X Drift-Y 0 5 10 15 20 25 30 35 40 45 50 55 0 0.5 1 1.5 2 No:ofstory Acceleration (g) Acceleration under SLE level Acceleration 0 5 10 15 20 25 30 35 40 45 50 55 0 0.2 0.4 0.6 0.8 1 No:ofstory velocity (m/sec) Velocity under SLE level velocity 0 5 10 15 20 25 30 35 40 45 50 55 0 0.005 0.01 0.015 No:ofstory Drift Drift under MCE Drift-X Drift-Y 0 5 10 15 20 25 30 35 40 45 50 55 0 0.5 1 1.5 2 No:ofstory acceleration (g) Acceleration under MCE Acceleration 0 5 10 15 20 25 30 35 40 45 50 55 0 0.5 1 1.5 2 2.5 No:ofstory velocity (m/sec) Velocity under MCE velocity
- 133. 133 Overall Nonstructural Damage under both SLE and MCE 4.7% 0.6% 0.2% 3.9% 23.17% 3.01% 0.84% 19.32% 0.0% 5.0% 10.0% 15.0% 20.0% 25.0% Total damage Architectural damage Mechanical and electrical damage Building content damage Percentageofdamage Service level earthquake Maximum considered earthquake
- 134. 134 Repair Cost of Nonstructural Damage under both SLE and MCE 35.48 6.17 6.36 22.95 183.61 58.11 17.31 108.19 0 40 80 120 160 200 Total damage Architectural damage Mechanical and electrical damage Building content damage Directeconomiccost(Million-peso) Service level earthquake Maximum considered earthquake
- 135. 135 Serious Injury and Casualty 0 200 400 600 800 1000 1200 1400 1600 Casulty (People) Serious injury (People) Total population Casulty (People) Serious injury (People) Total population Casulty (People) Serious injury (People) Total population Nighttime population distribution Daytime-HAZUS population distribution model Daytime-FEMA population distribution model 1 13 1432 1 4 403 1 7 716 0 1 0 1 0 1 POPULATION (PEOPLE) Service level earthquake Maximum considered earthquake
- 136. Using AI ad Machine Learning
- 137. 137 A Swing Towards the AI • Rich Pictures • Analytical Hierarchy Process (AHP) • Artificial Neural Networks (ANN) • Genetic Algorithms (GA) • Expert Systems (ES) • Machine learning (ML) • Fuzzy Logic • Deep Thinking • Big Data and Data Mining 137
- 138. 138 Using AI in Structural Design Process Architectural Design Preliminary Sizing Structural Modeling Structural Analysis Code Based Design Performance Based Design 138 Iterative, computationally intensive and time consuming
- 139. Our Approach
- 141. Model I: Prediction of Structural weight per floor area of building Building Target Wt/F.A (kN/sqm) Simulated Accuracy ELM MLP-BP ELM MLP-BP (B1) 14.12 14.46 14.63 0.976 0.963 (B2) 12.99 13.86 12.12 0.933 0.933 (B3) 11.47 13.01 12.24 0.865 0.933 (B4) 14.12 14.75 13.64 0.955 0.966 (B5) 14.12 14.72 13.21 0.957 0.946 14.12 12.99 11.47 14.12 14.12 14.46 13.86 13.01 14.75 14.72 14.63 12.12 12.24 13.64 13.21 B1 B2 B3 B4 B5 Target ELM MLP-BP 0.800 0.850 0.900 0.950 1.000 B1 B2 B3 B4 B5 Mean ELM MLP-BP The average accuracy of ELM network is about 94% The average accuracy of MLP-BP network is about 95% Accuracy
- 143. 143 Earthquake and Structures Source: Murty (2004) Force on Buildings Generated due to Acceleration at each Level
- 145. 145 What is Expected and can be Achieved
- 146. 146 49th Floor 26th Floor B1 Quick Summary of Event Based on Sensor Data Analysis Location of Epicenter Earthquake Event Magnitude 6.2 Location 13.99 N 120.67 E Depth 172.0 Km Time 2017-08-11, 05:28 UTC P H I L I P P I N E S Park Terraces Towers 1-3
- 147. 147 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 1 2 3 4 5 6 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 1 2 3 4 5 6 0 50 100 150 200 250 300 0 1 2 3 4 5 6 0 50 100 150 200 250 300 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 450 500 0 1 2 3 4 5 6 0 50 100 150 200 250 300 350 400 450 500 0 1 2 3 4 5 6 Frequent/Service-level Earthquake Recorded Earthquake Event Spectral Acceleration (g) – (X – Direction) Design-basis Earthquake (DBE - 475 Years Return Period) Maximum Considered Earthquake (MCE - 2475 Years Return Period) Frequent/Service-level Earthquake Recorded Earthquake Event Spectral Acceleration (g) – (Y – Direction) Design-basis Earthquake (DBE - 475 Years Return Period) Maximum Considered Earthquake (MCE - 2475 Years Return Period) Frequent/Service-level Earthquake Recorded Earthquake Event Spectral Velocity (mm/sec) – (X – Direction) DBE (475 Years Return Period) MCE - 2475 Years Return Period Spectral Velocity (mm/sec) – (Y – Direction) Frequent/Service-level Earthquake Recorded Earthquake Event DBE (475 Years Return Period) MCE - 2475 Years Return Period Frequent/Service-level Earthquake Recorded Earthquake Event Spectral Displacement (mm) – (X – Direction) DBE - 475 Years Return Period MCE - 2475 Years Return Period Spectral Displacement (mm) – (Y – Direction) Frequent/Service-level Earthquake Recorded Earthquake Event DBE - 475 Years Return Period MCE - 2475 Years Return Period Level of Seismic Hazard Posed by This Event
- 148. 148 In the view of practicing structural engineer a gap between what is taught and what is needed to practice in performance based design is filled by on job learning and knowledge acquired from experienced engineers
- 149. Thank you for your kind attention View publication statsView publication stats