Center studies collapse of concrete buildings

The Pacific Earthquake Engineering Research Center (PEER) was awarded a five-year, $3.6 million NEES Grand Challenge grant from the National Science Foundation (NSF) to study the collapse potential of older, nonductile concrete buildings during earthquakes. These buildings are pervasive throughout the United States and other countries, and are considered a high risk. According to PEER, the project will fully utilize the George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES) (www.nsf.gov/news/special_reports/nees/about.jsp ).

Nonductile concrete buildings were a prevalent construction type in highly seismic zones of the United States prior to enforcement of codes for ductile concrete in the mid-1970s, and are widespread in many countries. California alone has an estimated 40,000 of these buildings, including residential, commercial, and critical service facilities. The poor seismic performance of nonductile concrete buildings was evident in recent earthquakes, including Northridge (1994); Kobe, Japan (1995); Chi Chi, Taiwan (1999); Kocaeli, Duzce, and Bingol, Turkey (1999, 1999, 2003); Sumatra (2005); and Pakistan (2005).

For this project, PEER will study the vulnerability and toughening of nonductile concrete infrastructure against earthquake effects. Specifically, PEER’s research will develop procedures to identify the truly dangerous buildings from among the large building population, thereby turning an intractable problem into one that can be addressed with available resources. According to PEER, mitigation strategies developed during this study also can inform strategies to mitigate for other natural and manmade hazards such as hurricanes and explosions.

"Existing vulnerable buildings are the number one seismic safety problem in the world, and nonductile reinforced concrete buildings are a noteworthy percentage of these that have yet to be addressed in a systematic way," said Jack Moehle, PEER’s director. "This project will tackle this issue in a comprehensive way, leading to solutions that can save thousands of lives."

NEES, managed by NEES Consortium, Inc., in Davis, Calif., is a shared network of 15 experimental facilities, collaborative tools, a centralized data repository, and earthquake simulation software, all linked by the ultra high-speed Internet2 connections of NEESgrid. Together, these resources provide the means for collaboration and discovery in the form of more advanced research based on experimentation and computational simulations of the ways buildings, bridges, utility systems, coastal regions, and geomaterials perform during seismic events.

The PEER project team will include the following institutions and their respective departments: University of California (UC) at Berkeley–Architecture Dept. and Civil Engineering Dept.; UC Irvine–Civil Engineering Dept.; UC Los Angeles–Civil Engineering Dept.; San Jose State University–Civil Engineering Dept.; University of Puerto Rico at Mayaguez–Civil Engineering Dept.; University of Kansas at Lawrence–Civil Engineering Dept.; University of Washington–Political Science Dept.; Purdue University-Civil Engineering Dept.; and University of Southern California–School of Policy, Planning, and Development.

The project team is partnering with the Earthquake Engineering Research Institute to form the Concrete Coalition, an alliance of concerned engineers, planners, policy experts, and other stakeholders who will work with the project team to develop and implement effective mitigation strategies.

Research will concentrate on four areas:

1. Exposure-An inventory of older-type concrete buildings will be developed for one urban region to serve as a testbed for regional loss studies.
2. Component and system performance-Laboratory and field experiments will be conducted on concrete components and soil-foundation-structure systems to improve understanding of conditions that lead to collapse.
3. Building and regional simulation-Computer models and simulations will be developed and used to study regional distribution of building collapses in a major earthquake.
4. Mitigation strategies-Effective mitigation strategies will be developed to promote action for risk reduction.

Expected outcomes of PEER’s study include improved inventory, data, and models for components and subsystems, single-building simulation capabilities, improved fragilities/regional simulations, public policy, improved engineering assessment and retrofit tools, increased diversity in earthquake engineering, and active rehabilitation of truly vulnerable buildings nationwide initiated through public policy and professional encouragement.