Performance-Based Seismic Design: International Practices

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d l i u Performance-Based Seismic Design: B t l l a t a i International Practices b T a n H o l n i c rba Professor Guo-Qiang Li, n u o Tongji University, Shanghai,U C nd China © a Ron Klemencic, President Magnusson Klemencic Associates, USA

       

CTBUH Seismic Workshop Eight Countries Participated gs

n Australia/New Zealand i d l i Chile u B t l l a China t a i b T a Indonesia n H o l n i Japan c rba n Korea ou U C nd Philippines © a USA

Code-Based Seismic Design

s g All countries have codes that cover basic n i d l seismic design requirements i u B t l l a t a i b T a n H o – Minimum acceptable lateral l n i strength c a and stiffness n b r u U o – acceptable detailing C nd Minimum © a practices 

Performance-Based Seismic Design

s g Required for Tall/Irregular n Alternate Design Approach i d l i Buildings u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a China and Japan

Indonesia, Philippines, USA

Consistent Goals of PBSD

s g  A “decision maker” states a desire that a n i d l i building be able to “perform” u in a certain way: B t l  Protect life safety l a t a i b T  Minimize potential repair cost a n H o l  Minimize disruption of use n i c rba n u U o C nd uses his or her skill to provide  The “engineer” © a a design that will be capable of achieving these objectives

Seismic Demand Definition

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Code

PerformanceBased Design

d l i u • Frequent B t l l aperiod, t – Commonly around 50 year return a i b T a n H o l i • ExtremelycRare an n b r u 1,000 – Commonly to 2,500 year return period U o C nd © a • Intermediate (Design Level) – Commonly around 500 year return period

Performance Objectives

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d l i + u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a Ground Motion x% - 50 years





Performance Level

Design Ground Shaking

Acceptable Performance Level (maximum acceptable damage, given that shaking occurs)

Performance Levels

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a

Operational

Immediate Occupancy

Frequent EQ

Life Safety

Intermediate EQ

Collapse Prevention

Extremely Rare EQ

Computer Models • Frequent and Intermediate d l i u (Design Level) EQ B

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t l l a – 3D linear elastic modela t i b T a – Used to initially proportion n H o n elements cil a n b r u U o C nd © a

Computer Models • Extremely Rare EQ

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d l i u – 3D non-linear B t l l a t model a i b T a n – Dynamic Time H o l n i History Analysis c a n b r used u U o d – StaticC (Push-over) n © a also used in Chile, China and Japan

■ Japan Requirements Current Japanese Code Procedure Building Height ≦ 60m

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o (1), (2) andC (3) are the seismic design methods d nelasto-plastic pushover based© on static and/or a analysis. No

Yes

Alternative Methods

(1)

Allowable stress and horizontal load-carrying capacity calculation

(2)

Response and limit capacity calculation

(3)

(4)

Other methods equal or superior to (1) or (2)

Time-history dynamic response analysis

· ·Design review and

evaluation by the panel members, and special permission are required.

Masayoshi Nakai

■Definition of Seismic Demand Level (Japan) Design input motions for horizontal direction ( Example of Notification motions) 2000

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a (1.5×ERE)

1750 1500

Acceleration (cm/sec2)

Amplification factor (:Gs) of acceleration for the standard surface ground (:soil type 2) is considered. (: the abbreviated calculation)

(ground surface)

Extremely Rare Earthquakes (ERE)

1250

(ground surface)

Return Period: RE: 50 years

1000 750

ERE: 500 years

(exposed bedrock)

(5 times)

500

Rare Earthquakes (RE)

250

(ground surface) (exposed bedrock)

0 0.1

0.5

1

5

10 Period (sec.)

Acceleration response spectra for the Notification motions ( h=5% )

Masayoshi Nakai

■Performance Objectives (Japan) Summary of performance objectives / minimum requirements

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a Demand levels

Performance General objectives or minimum Drift story angle requirements Story ductility factor

Stresses in each structural elements

Ductility factor of each structural elements

Rare Earthquakes (RE)

Extremely Rare Earthquakes (ERE)

Damage Limit

Collapse Limit

1/200 or less

1/100 or less 2.0 or less

Short-term allowable stress or less

4.0 or less

Masayoshi Nakai

Korean Seismic Performance Objectives

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a 2) Seismic Design Code

CHANG MINW OO

Design Earthquake Level （Korea）

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a 2) Seismic Design Code

CHANG MINW OO

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The Chilean Practice in Seismic Design

s g n i Chile has several loading and design codes, d l i differentiated by their function or structural system. u B t l l a The loading codes are: t a i b T  NCh433 for Residential and Office Buildings a nIsolated H o  NCh2745 for Base Buildings l n i  NCh2369 for Facilities c Industrial a n b r u o Performance Based U Design: Not in the Codes C d n number of special projects,  On a limited © a  Non-linear analysis models (push-over, time history)  To identify failure mode and performance level

CTBUH 2012 9th World Congress

renelagos engineers


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Elastic demands of Chilean Codes: (PE: 10% in 50 years)


NCh 2745 Of 2003 for Base Isolated Buildings NCh 433 Of 2009 for Residential and Office Buildings NCh 2369 Of 2003 for Industrial Facilities

NCh 2745 NCh 2745

NCh 433 NCh 433 NCh 2369


Acceleration Spectra

renelagos engineers


s g NCh 433 Of 2009 Chilean Seismic Code for Buildings: n i d l i  Type of analysis: Modal spectrumu analysis - Linear elastic B  Design loads: Elastic response reducedt by R* l l a t a i  Base Shear: ≥ Minimum Base shear b T  Drift control: At the Center a of Mass and at perimeter n H o l n i c rba n u U o C nd © a Elastic Spectrum: Sa (seismic zone 3)


Design Earthquake: are reduced forces by R*

renelagos engineers


s g NCh 433 Of 2009 Chilean Seismic Code for Buildings: n i d l i u Base shear limitations: B t l l  IA P/6g ≤ Base shear ≤ 0.35 SIA P/gita a b T a  If Base Shear is outn of range, forces and H o be scaled displacements imust to the exceeded limit. l n c a n b  Minimum base shearr for normal buildings: u U 2 is 5.0%P oseismicdZone - VCin ©- V in seismic an Zone 3 is 6.7%P o

o

bs bs


renelagos engineers

Seismic Design Procedure Specified By AS1170.4 (2007) s

g n i • Life safety and collapse prevention are the primary d l i performance objectives u B t l l a • Force-based design approach depending on: t a i b T a – building importance level n H o l – level of seismic hazard n i c a n b – site condition r u U o – building height C nd © a • Concrete and steel codes specify detailing requirements depending on the level of ductility demand

Kourosh Kayvani

Performance-based Measures in AS1170.4 (2007) s

•

•

•

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d l i Largely a prescriptive code, with some performance-based u B measures in the context of life safety and collapsetprevention. l l a t a i b T a Recognition of four levels n of importance with seismic hazards H o l corresponding to return periods typically between 500 to 2500 n i c a n b years. r u U o C d n Nonlinear analysis allowed for obtaining © statica(push-over) Structural Performance factor (S ) and ductility factor (µ) p

Kourosh Kayvani

Performance-based Measures in AS1170.4 (2007) s

•

•

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d l i Serviceability limit state (SLS) performance objective is u B t considered only for buildings of the highest importance level l l a t a i (of 4) to remain serviceable immediately after lower return b T period (500 years) earthquake shaking.a n H o l n i c a n b Limits storeyudrift, typically to 1.5% of story height, primarily r U o for maintaining structural integrity rather than limiting C d damage. © an Kourosh Kayvani

PEER TBI Guidelines in US • The Goal:

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– to provide guidance for the seismic design and review of tall buildings – to streamline the design and review process – to lead to consensus on best practices that’s widely supported

• It’s a rule book to a game with no rules

PEER TBI Guidelines – Service Level • Service Earthquake:

•

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d l i – 43-year return period u B t l – 2.5% damped spectra l a t a i b T a n H o n il PerformancecGoal: a n b r u compromise – Doesonot structure’s safety U C notnrequired d – Repair for occupancy © a – Essentially elastic response

PEER TBI Guidelines – MCE Level • Maximum Considered Earthquake •

• •

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d l i – 975 year-return period u B t l l a t Performance Goal a i b T – Minor risk of collapsen(~10%) Ha o l – Modest residuali drift (< 1%) n c rba n u response U 3-D nonlinear history analysis (Perform) o C nd © acceptance a Different criteria for – Deformation-controlled elements – Force-controlled elements

Performance-Based Seismic Design in China

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d l i u • the minor earthquake: 50 years return period B t l l a t a i • the moderate earthquake: 475 years return period b T a n H o • the severe earthquake: 1600～2400 years return period l n i c rba n u U o C nd © a Three levels of earthquakes

If

I

Ir


s g n Target performances of Buildings i d l i u B t l l a  No damage under minor earthquakes t a i b T a n  Repairable under moderate earthquakes H o l n i c a n b  No collapse under severe earthquakes r u U o C nd © a


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Building performance objectives under various earthquakes


Performance objective level

1

2

3

Minor earthquake

No damage

No damage

No damage

No damage

Slight damage

Minor damage

Moderate earthquake

No damage

Minor to moderate damage

Usable after normal maintenance

Usable after slightly repair

Deformation <3[ ∆U e]

Moderate damage

Serious damage

for normal use

Slight damage

Severe earthquake

Usable after normal maintenance

Minor to moderate damage Usable after repair

Usable after strengthening

4

Usable after heavy repair

Inter-story drift requirements of various performance objectives

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Performance objective level

Minor earthquake

Moderate earthquake

1

far less than [θe]

less than [θe]

slightly larger than [θe]

far less than [θe]

slightly larger than [θe]

less than 2 times of [θe]

much less than [θe]



less than [θe]


less than 0.9 times of [θp]

2

3

4

Severe earthquake


Provisions of PBSD in code 2010

s g Limit of relative inter-story driftsin d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a

Structural material

Type of structure

[θe]

[θp]

Frame

1/550

1/50

1/800

1/100

Shear wall, Frame tube-Core tube

1/1000

1/120

Multi-story and tall structures

1/250

1/50

Frame-Shear wall,

Reinforced concrete

Steel

Frame-Core tube

Convention Centro for Shanghai Expo 2010

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Architecture of Convention Centro

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Structure of Convention Centro

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d l i u B t l l a t a i b T a n H o l n i c rba n u U o C nd © a Mega-frame (span: 54m)

Under construction

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Application of buckling restrained braces (BRB) in Shanghai Expo Center

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Target seismic performance

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Minor earthquake

Moderate earthquake

Severe earthquake

Global behavior

No damage

Repairable

Collapse prevention

Limit of inter-story drift

1/300

1/100

1/50

Columns

Elastic

Elastic

Limited plastic deformation

Beams

Elastic

Elastic


Ordinary braces

Elastic

Elastic


BRB

Elastic

Plastic

Plastic


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Steel consumption

d l i u Structural B t Braces Beams Columns Trusses l system l a t a i b T a n BRBF 431t 2341t 3063t 1959t H o l n i c a n b CBF 1120t 2458t 3271t 1959t r u U o C nd © a

Total 7794t 8808t

Summary

• Performance-based Seismic Design allows s g n for cost-savings and better understanding of i d l i the building’s performance. u

B t l l a t a i b T a n H o l n i c rba n u U o C nd © a Global Financial Tower 492m

Jinmao Tower 420m

Shanghai Center Tower 632m

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d l i u B t l l a t a i Thank you for your attention! b T a n H o l n i c rba n u U o C nd © a

Performance-Based Seismic Design: International Practices

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