Panel Discussion: PBEE Practice and Needs

Paul Somerville, URSJoe Maffei, R&C

Ron Hamburger, SGHLloyd Cluff, PG&E

Tom Shantz, CaltransJim Malley, Degenkolb

Overview – Jim Malley Many significant accomplishments in

multiple areas PBEE methodology, becomes foundation for

application specific tasks Non-ductile concrete advances Ground motion work, especially NGA Procedure for quantifying system

performance (ATC-63) Lifelines, bridges and systems analysis

applications Life beyond NSF looks bright!

Earthquake Ground Motion

Paul Somerville

Lack of suitable recorded time histories for seismic design in the Western U.S.

Complexity of damage patterns and the challenge of urban seismic zonation

Lack of suitable recorded time histories for seismic design

The fine work of the PEER NGA Program notwithstanding, design earthquakes in most parts of the Western United States are from larger earthquakes and/or closer distances than are represented in the NGA data base

Earthquake science is being applied to fill this gap, e.g. in the Tall Bldgs Initiative

We do not have recorded time histories for the design earthquake in most parts of the western United States.

We need to rely on simulated time histories like those below.

Complexity of Damage Patterns - the Challenge of Urban Seismic Zonation

Damage is often not simply related to surface geology – the current code approach using Vs30 for soils leaves many unexplained effects

Very dense urban strong motion arrays (spacing < 1 km) combined with simulations are needed to advance our understanding of the blotchy nature of earthquake damage patterns

Northridge Earthquake Red tagged buildings occurred in clusters

The Sherman Oaks cluster is not understood

The Santa Monica and West LA cluster is related to the edge of the LA Basin formed by the Santa Monica fault

Earthquake Forecasting

Earthquake prediction (location, time and magnitude of a specific earthquake) is not currently possible, but

Earthquake forecasting (changes in likelihood of earthquakes over months to years) may soon become viable

How should engineering practice respond?

Earthquake forecast for Japan just before the 2000 Tottori earthquake

The forecast showed high probability for that earthquake (marked by the cross) and the 2004 Niigata Chuuetsu earthquake to the northeast

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STEEL GRAVITY

FRAMING

Collapse Prediction in Evaluation Guidelines

Performance EvaluationApproach

Joe’s

Beer!Beer!Food!Food!

Beer!Beer!Food!Food!

Joe’s

Beer!Beer!Food!Food!

Joe’s

Pacific Earthquake Engineering Research CenterJune 13, 2007San Francisco

Summative Meeting Panel Discussion:PBEE Practice and Needs

Lloyd S. CluffPacific Gas and Electric Company

Director, Earthquake Risk ManagementGeosciences Department

Perspectives on 10 years of Earthquake Engineering ResearchPEER

Perspectives

Strategy to establish PEER 1995-96 Role of California Seismic Safety Commission Role of Pacific Gas and Electric Company Lifelines component of PEER User needs-driven research agenda Public/Private/Partnerships (PPP) Leveraged funding

Accomplishments and Future DirectionsAccomplishments Leveraged funding

PPP (PG&E, Caltrans, CEC, FEMA, BART) 1996 – 2007 ~$12.5 million Implementation of research results

Useful research results that can be implemented Managing earthquake risks

Improve system performance

Future Directions Lifeline interdependencies during earthquakes

Highways and bridges/Power utilities/Water supply System performance

Individual lifelines Lifeline groups