Dr. Naveed Anwar

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

Naveed Anwar, PhD

Dr. Naveed Anwar2

Excellencethe quality of being outstanding or

extremely good

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

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What a Structural Engineer said !

Hardy Cross, 1885-1959

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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

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The First Code - Hammurabi's (1772 BC)

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.

Implicit Requirements

Consequence of non-Performance

Explicit Collapse Performance

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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”

Modern Codes, c2000

PrescriptiveLaw of Moses (1300 BC)

The Bible, Book of Deuteronomy, Chapter 22, Verse 8

Performance Oriented

Ref: Teh Kem, Associate Prof. NUS

Dr. Naveed Anwar

Formal, Modern Buildings Codes

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“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 1844.

In USA, the City of Baltimore first building code in

1859.

In 1904, a Handbook of

the Baltimore

City

In 1908 , a formal

building code was

drafted and adopted.

The International Building Code (IBC) by (ICC).

European Union,

the Eurocodes.

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Ancient masterpieces were built before the modern codes

Master builders had freedom to dream and to realize them

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Public Safety and Disaster Resilience

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Population

Urbanization and Un-planned

development

Inappropriate Built

Environment

Lack of Resources for Communities

Natural or Man-made Phenomena

Disaster Hazard ExposureVulnerability

To reduce risk of disaster and increase safety,

we need tp estimate hazard properly,

and Reduce Vulnerability

Risk

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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 …

Dr. Naveed Anwar

The Modern Codes – With “intent” to make buildings safe for public

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(ACI 318 – 14)

Extremely Detailed prescriptions and equations using

seemingly arbitrary, rounded limits with

implicit meaning

(IS 456-2000)

Dr. Naveed Anwar

The General Structural Code Families

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UBC, IBC

ACI, PCI, CRSI, ASCE, AISI,

AASHTO

BS, SG, IS, MNBC, NBC, PBC, ….

Euro-codes China, USSR, Japan

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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

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A Move Towards Performance Based

• Prescriptive Codes restrict and discourage innovation

• Performance Based approach encourages and liberates it

Objective RequirementsPrescribed

Solution

Objective RequirementsAlternate Solution

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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

Dr. Naveed Anwar

Ensuring Explicit Safety Performance(And increase Disaster Resilience)

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Common Hazards leading to Safety Concerns

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Indicator Level

Earthquake Related

Wind Related Water Related Fire Related

GlobalDrift, Overturning, Sliding

Drift, Overturning, Sliding, Uplift

Sliding, Floatation Stability

MemberStrength, Ductility, Deformation

Strength, Deformation,

Water tightness, Strength, Deformation

Fire rating

ConnectionStrength, Ductility, Stability

Strength, Stability Strength, Stability, water tightness

Fire rating

Material Ductility, Strength Wind perviousWater proof/ water resistant

Fire proof, fire resistant

Broad Performance Indicators

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Integrated Disaster Resilient Design

Design

Process Step

Design Considerations

Earthquakes Cyclones, Typhoons Floods Landslide

Loc

atio

n

Pla

n &

La

yo

ut

Ap

pro

pria

te

Ma

teria

l

Str

en

gth

&

inte

grity

Eva

cu

atio

n

Loc

atio

n

De

sig

n E

lem

en

ts

Ma

teria

l

Se

lec

tio

n

Str

en

gth

&

inte

grity

De

bris

Loc

atio

n

Ba

sic

De

sig

n

Mitig

atio

n P

lan

Ma

teria

l U

sag

e

Loc

atio

n

Mitig

atio

n P

lan

Site Selection

Construction

Practices

Architectural Planning

Structural Design

Plumbing Design

Electrical

Waste Disposal

Material Selection

Regional Planning

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Performance based design can be applied to any type

of loads, but was initaily

developed and targeted for

earthquake loads

Earthquakes as a Catalyst for PBD

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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”

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Performance Level Definitions

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

GuidelinesPeer Review

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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

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Define Performance Levels

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Based on FEMA 451 B

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Link the Hazard to Performance Levels

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Structural Displacement

Lo

adin

g S

ever

ity

Resta

urant

Resta

urant

Resta

uran

t

Haz

ard

Vulnerability

Consequences

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How to Work with PBD

Dr. Naveed Anwar

Progression and Future Directions in PBD

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Design Approaches

Intuitive Design

Code Based Design

Performance Based Design

Consequences and Risk Based Design

Resilience Based Design

Dr. Naveed Anwar

Design Approaches

Intuitive Design

Code Based Design

Performance Based Design

Consequences and Risk Based Design

Resilience Based Design

Dr. Naveed Anwar

Design Approaches

Intuitive Design

Code Based Design

Performance Based Design

Consequences and Risk Based Design

Resilience Based Design

Dr. Naveed Anwar

Design Approaches

Intuitive Design

Code Based Design

Performance Based Design

Consequence and Risk Based Design

Resilience Based Design

Dr. Naveed Anwar

Design Approaches

Intuitive Design

Code Based Design

Performance Based Design

Consequences and Risk Based Design

Resilience Based Design

Dr. Naveed Anwar

Green Buildings Resilient Buildings

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Main authors : ArupSupported by USRC and many others

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• Explicit confirmation of higher or expected performance level using innovative solutions

Performance Based Design

• Get the best “value” for resourcesValue Engineering

• Provide an independent view and confirmation

Peer Review

Dr. Naveed Anwar

Some Case Studies

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PBD andAsian 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

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Gramercy Residences

(72-story)Knightsbridge Residences

(64-story)

Trump Tower

(56-story)

Milano Residences

Some Projects in Makati, Philippines

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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

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Acqua Private ResidencesMandaluyong City,

Philippines

Niagara Tower

(42-story )

Sutherland Tower

(44-story)

Dettifoss Tower

(46-story)

Livingstone Tower

(53-story)

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Ninoy AcquinoInternational 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

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Star View ResidencesBangkok

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R & D to Enhance Performance

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Application of PBD to PC Hybrid Buildings

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The Plan

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Modeled and Design for Two Approaches

117.9 m

(38 Stories)

Transfer

Beams

Residential

Floors

Cast-in-Place

Shear Walls

Precast

Concrete Walls

RC Walls

Car Parking FloorsRC Columns

Roof

Code Based Design – Linear Model PBD – Nonlinear Model

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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

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Client

PBD Value Engineering

Peer Review

Basic Design

Public Officials

Design Codes and Guidelines

High performance, Higher safetyhigher value, cost effectiveSustainable

Excellence in Construction

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