development of next-generation performance-based seismic design guidelines atc 58 performance...

Development of Next-Generation Performance-Based Seismic Design Guidelines

ATC 58 Performance Assessment ATC 58 Performance Assessment Calculation Tool (PACT)Calculation Tool (PACT)


What is PACT?What is PACT?

• PACT is intended to be an open-source, engineer-friendly, software system coded entirely in VB 6.0 and Fortran.

• It is a small part of a very large effort (ATC-58)

• PACT is an implementation of the PEER PBEE methodologyProbability of

• Death• Dollars • Downtime

Only this one at this time


What Goes Into PACT?What Goes Into PACT?

• PACT gathers and stores very Basic Building Information To the extent needed to define

• basic proportions (plan dimensions, story heights, perimeter length)• Structural system• Nonstructural systems and components• Contents

• User specified correlation of damage for performance groups (currently binary)

• Extent of other information needed is a function of user’s expertise Basic Assessment (very little, if any)

• Modification of default quantities Enhanced Assessment (from little to extensive)

• Specification of detailed quantities and repair costs• Adding new and modifying existing performance groups and fragility functions

• Engineering Demand Parameters Estimates of story drifts and accelerations at each floor

• (H-Dir-1, H-Dir-2, and Non-directional)


Performance Group Damage Performance Group Damage States and FragilitiesStates and Fragilities

Damage state threshold

Required/ optional

Demand parameter

iDSEDP

Median EDP

iDSEDP Uncertainty,beta

iDS

DS0 (no damage) Required DS1 Optional DS2 Optional DS3 Optional etc. Optional

DSj (complete damage)

Required

Force or displacement demand from

structural analysis

Value of demand for which the DS has a 50% chance of occurring (and of not occurring)

Associated with components only; independent of IM

None

Complete

DS1 DS2 DS3 DSj

0

0.5

1.0

P iDS DS

EDP1EDP 2EDP 3EDP jEDP

ln1

Pi i

iDS DS

EDPDS DS EDP

EDP

None

Complete

DS1DS1 DS2DS2 DS3DS3 DSjDSj

0

0.5

1.0

P iDS DS


ln1

Pi i

iDS DS

EDPDS DS EDP

EDP


Correlation of DamageCorrelation of Damage

P(DS2)=0.60P(DS2)=0.60

0 1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

P(D

S>

= D

Si)

DS0 DS1 DS2 DS4

Interstory drift, %

EDPi

P(DS4)=0.07P(DS4)=0.07

P(DS3)=0.26P(DS3)=0.26

P(DS0)=0.07

Randomly generated horizontal


What does PACT do with this What does PACT do with this information?information?

• PACT takes the basic building information provided and,• a set of engineering demand parameters for the building (say results of

5, 10 or 20 nonlinear dynamic response analyses for a given scenario or hazard level, PACT gathers and stores very Basic Building Information and,

• It performs simulations using Cholesky Decomposition to generate 100s of realizations

• Based on these realizations, PACT generates probability of loss curves for the entire building, a particular floor, a particular direction, or a single component.

• Results are presented in a uniform fashion across various levels of generalization and can be saved and exported to Excel, text files, and various graphic formats.

• PACT is an XML based product and all of the input, intermediate, and output data is preserved in a hierarchical format that can be retrieved, modified, and enhanced at any time.


Performance Group Damage Performance Group Damage States and FragilitiesStates and Fragilities

Damage state threshold

Required/ optional

Demand parameter

iDSEDP

Median EDP

iDSEDP Uncertainty,beta

iDS

DS0 (no damage) Required DS1 Optional DS2 Optional DS3 Optional etc. Optional

DSj (complete damage)

Required

Force or displacement demand from

structural analysis

Value of demand for which the DS has a 50% chance of occurring (and of not occurring)

Associated with components only; independent of IM

None

Complete

DS1 DS2 DS3 DSj

0

0.5

1.0

P iDS DS


ln1

Pi i

iDS DS

EDPDS DS EDP

EDP

None

Complete

DS1DS1 DS2DS2 DS3DS3 DSjDSj

0

0.5

1.0

P iDS DS


ln1

Pi i

iDS DS

EDPDS DS EDP

EDP


Correlation of DamageCorrelation of Damage

P(DS2)=0.60P(DS2)=0.60

0 1 2 3 4 5 6 7 80

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

P(D

S>

= D

Si)

DS0 DS1 DS2 DS4

Interstory drift, %

EDPi

P(DS4)=0.07P(DS4)=0.07

P(DS3)=0.26P(DS3)=0.26

P(DS0)=0.07

Randomly generated horizontal


Let us take a look at it!Let us take a look at it!

Viewer Discretion Is Advised

PACT is a product still under development and every thing about it changes several times everyday.

What I show you is basically the “Enhanced Assessment Option.” I comment on where and how the “Basic Assessment Option would be different

For complete legal jargon, see me after this session.

We have the informed consent of the audience. Proceed!


A demonstration of PACT as is A demonstration of PACT as is nownow


PACT Analysis TypesPACT Analysis Types

• Intensity-based assessmentswhat are the chances of losses of given amount, if

the building is subjected to ground motion of specific intensity?

• Scenario-based assessmentswhat are the chances of experiencing more than

$10M damage from a M6 on the San Andreas Fault?

• Time-based assessmentwhat are the chances of losses exceeding a given

amount, over a given time period?


Time-based AssessmentTime-based Assessment

• You already saw how intensity and scenario based assessments are done.

• For time-based assessment, the user is asked to upload or enter a hazard curve.


Time-based AssessmentTime-based Assessment

• Then the user is asked to associate a set of previous runs with particular points on the hazard curve.

• PACT then performs integrations generating a loss surface and annualized loss curves.

• Annualized loss curves may be combined and manipulated exactly as other loss curves.

0.5 1 1.5 2 2.5 3 3.5 40

0.05

0.1

0.15

0.2

0.25

Capital losses ($M)

Annual probability of being exceeded

Annualized loss before retrofit= $100k

Annualized loss after retrofit= $60k

0.5 1 1.5 2 2.5 3 3.5 40

0.05

0.1

0.15

0.2

0.25

Capital losses ($M)

Annual probability of being exceeded

Annualized loss before retrofit= $100k

Annualized loss after retrofit= $60k


Thank you.Thank you.

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