Catalyzing Innovation in Performance-Based Design for Disaster Resilient Buildings and Structures

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1 Naveed Anwar, PhD Catalyzing Innovation in Performance-Based Design for Disaster Resilient Buildings and Structures

2 Excellence the quality of being outstanding or extremely good 2

3 To be Excellent, something must be above average, better than standard, and of higher performance 3

4 What a Structural Engineer said! Hardy Cross,

5 Building Industry relies on Codes and Standards Specify requirements Give acceptable solutions Prescribe (detailed) procedures, rules, limits Mostly based on experience and not always rational Spirit of the code to provide Public Safety and Convenience Compliance to letter of the code is indented to meet the spirit 5

6 The First Code - Hammurabi's (1772 BC) Implicit Requirements Explicit Collapse Performance Consequence of non-performance Clause 229: If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death. 6

7 Public Safety and the Codes In case you build a new house, you must also make a parapet for your roof, that you may not place bloodguilt upon your house because someone falling might fall from it - Prescriptive Modern Codes, c2000 Ref: Teh Kem, Associate Prof. NUS Performance Oriented Law of Moses (1300 BC) The Bible, Book of Deuteronomy, Chapter 22, Verse 8 7

8 Formal, Modern Buildings Codes Rebuilding of London Act after the Great Fire of London in 1666 AD. In 1680 AD, The Laws of Indies Spanish Crown London Building Act of In USA, the City of Baltimore first building code in In 1904, a Handbook of the Baltimore City In 1908, a formal building code was drafted and adopted. The Internatio nal Building Code (IBC) by (ICC). European Union, the Eurocodes. 8

9 Ancient masterpieces were built before the modern codes Master builders had freedom to dream and to realize them 9

10 Public Safety and Disaster Resilience

11 Lack of Resources for Communities Population Natural or Man-made Phenomena Inappropriate Built Environment Urbanization and Unplanned development Disaster Hazard Vulnerability Exposure Risk To reduce risk of disaster and increase safety, we need tp estimate hazard properly, and Reduce Vulnerability 11

12 How modern codes intent to ensure Safety Define appropriate/estimated hazard or load levels Prescribe limits on structural systems, members, materials Define procedures for analysis and design Provide rules for detailing Provide specifications for construction and monitoring Hope that all of this will lead to reduced vulnerability and safer structures 12

13 The Modern Codes With intent to make buildings safe for public (ACI ) Extremely Detailed prescriptions and equations using seemingly arbitrary, rounded limits with implicit meaning (IS ) 13

14 The General Structural Code Families UBC, IBC ACI, PCI, CRSI, ASCE, AISI, AASHTO BS, SG, IS, MNBC, NBC, PBC,. Euro-codes China, USSR, Japan 14

15 Prescriptive Codes A Shelter Public Will the building be safe? Owner Will the building collapse/ will it be damaged? Can I use the building after a given earthquake? How much will repair cost? How long will it take to repair? Can I make building that will not be damaged and will not collapse Structural Engineer: Not sure, but I did follow the Code As long as engineers follow the code, they can be sheltered by its provisions 15

16 A Move Towards Performance Based Prescriptive Codes restrict and discourage innovation Objective Requirements Prescribed Solution Performance Based approach encourages and liberates it Objective Requirements Alternate Solution 16

17 Motivation for PBD 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 17

18 Ensuring Explicit Safety Performance (And increase Disaster Resilience)

19 Common Hazards leading to Safety Concerns 19

20 Broad Performance Indicators Indicator Level Earthquake Related Wind Related Water Related Fire Related Global Drift, Overturning, Sliding Drift, Overturning, Sliding, Uplift Sliding, Floatation Stability Member Strength, Ductility, Deformation Strength, Deformation, Water tightness, Strength, Deformation Fire rating Connection Strength, Ductility, Stability Strength, Stability Strength, Stability, water tightness Fire rating Material Ductility, Strength Wind pervious Water proof/ water resistant Fire proof, fire resistant 20

21 Location Plan & Layout Appropriate Material Strength & integrity Evacuation Location Design Elements Material Selection Strength & integrity Debris Location Basic Design Mitigation Plan Material Usage Location Mitigation Plan Integrated Disaster Resilient Design Design Considerations Earthquakes Cyclones, Typhoons Floods Landslide Design Process Step Site Selection Construction Practices Architectural Planning Structural Design Plumbing Design Electrical Waste Disposal Material Selection Regional Planning 21

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23 Earthquakes as a Catalyst for PBD Performance based design can be applied to any type of loads, but was initaily developed and targeted for earthquake loads 23

24 Explicit Performance Objective in PBD Performance based design investigates at least two performance objectives explicitly Service-level Assessment Codes arbitrary implicit Design Level Collapse-level Assessment Ensure continuity of service for frequent hazards (Earthquake having a return period of about 50) Ensure Collapse prevention under extreme hazards (the largest earthquake with a return period of 2500 years) 24

25 Performance Level Definitions Owner Engineer Will the building be safe? Can I use the building after the hazard? How much will repair cost in case of damage? Free to choose solutions, but ensure amount of yielding, buckling, cracking, permanent deformation, acceleration, that structure, members and materials experiences How long will it take to repair? Need a third party to ensure public safety and realistic Performance Guidelines Peer Review 25

26 Performance Objectives fro Sesimic Design 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 26

27 Define Performance Levels Based on FEMA 451 B 27

28 Link the Hazard to Performance Levels Loading Severity Hazard Resta urant Resta urant Consequences Resta urant Vulnerability Structural Displacement 28

29 How to Work with PBD 29

30 Progression and Future Directions in PBD

31 Design Approaches Intuitive Design Code Based Design Performance Based Design Consequences and Risk Based Design Resilience Based Design

32 Design Approaches Intuitive Design Code Based Design Performance Based Design Consequences and Risk Based Design Resilience Based Design

33 Design Approaches Intuitive Design Code Based Design Performance Based Design Consequences and Risk Based Design Resilience Based Design

34 Design Approaches Intuitive Design Code Based Design Performance Based Design Consequence and Risk Based Design Resilience Based Design

35 Design Approaches Intuitive Design Code Based Design Performance Based Design Consequence s and Risk Based Design Resilience Based Design

36 Green Buildings Resilient Buildings Main authors : Arup Supported by USRC and many others 36

37 Performance Based Design Explicit confirmation of higher or expected performance level using innovative solutions Value Engineering Get the best value for resources Peer Review Provide an independent view and confirmation 37

38 Some Case Studies

39 PBD and Asian Institute of Technology, AIT Research labs to support innovation More than 70 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 39

40 Knightsbridge Residences (64-story) Milano Residences Gramercy Residences (72-story) Trump Tower (56-story) Some Projects in Makati, Philippines 40

41 Park Terraces Located in Makati City, Philippines Two 50-story towers, one 62 story tower Remove perimeter beams, for better View First application of buckling restrained brace (BRB) system in Philippines 41

42 Sutherland Tower (44-story) Dettifoss Tower (46-story) Livingstone Tower (53-story) Niagara Tower (42-story ) Acqua Private Residences Mandaluyong City, Philippines 42 42

43 Ninoy Acquino International Airport Terminal 1 Performance Based Approach used for Disaster Resilience Traditional Code Based Review would make it unfeasible Seismic evaluation and retrofit design Evaluate for Collapse Prevention structural performance level under strong earthquakes 43 43

44 Star View Residences Bangkok 44

45 R & D to Enhance Performance 45

46 Application of PBD to PC Hybrid Buildings 46

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48 The Plan 48

49 Modeled and Design for Two Approaches Roof Residential Floors m (38 Stories) Cast-in-Place Shear Walls Precast Concrete Walls RC Walls Car Parking Floors Transfer Beams RC Columns Code Based Design Linear Model PBD Nonlinear Model 49

50 PBD Findings and Fixes No. Components Actions Comments for Seismic Evaluation at MCE level 1 Shear Walls Flexure OK Shear Increase horizontal reinforcements and wall thickness 2 Columns Flexure OK Shear Increase horizontal reinforcements and column size 3 RC Walls Flexure Increase confinement reinforcements (2 Stories) Shear Increase horizontal reinforcements (2 Stories) 4 PC Walls Flexure Increase confinement reinforcements (2 Stories) Shear Increase horizontal reinforcements (2 Stories) 5 Plies Axial OK 6 Foundations Flexure OK Shear OK 7 Transfer Beams Flexure Increase longitudinal reinforcements Shear Increase horizontal reinforcements 8 Coupling Beams Flexure OK Shear Increase horizontal reinforcements 50

51 Excellence in Construction Design Codes and Guidelines High performance, Higher safety higher value, cost effective Sustainable Peer Review PBD Basic Design Value Engineering Client Public Officials 51

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