A noontime series of seminars hosted by PEER and the Earthquake Engineering Research Institute (EERI) formed part of the activities of the EERI-Berkeley student chapter this semester. The seminars are intended to foster student interest in both organizations by providing a forum for interaction between students and internationally known experts in earthquake hazards mitigation. Ken Elwood, a PEER Ph.D. candidate, is the series coordinator.
The topic of the January kickoff seminar was the September 21, 1999, Chi-Chi, Taiwan, Mw 7.6 earthquake. The speakers were Norman Abrahamson, Senior Seismological Engineer of Pacific Gas and Electric Co., Nicolas Sitar, UC Berkeley Professor of Geotechnical Engineering, and Jack Moehle, Professor of Civil Engineering and PEER Director. The speakers were members of reconnaissance teams investigating the earthquake. The earthquake occurred in one of the most densely seismically instrumented regions in the world and therefore provided a trove of data for research purposes. A great many recordings of strong motion were obtained in the near field, a subject of great attention in earthquake engineering.
PG&E Senior Seismologist Norman Abrahamson
The February seminar by Robert Youngs, of Geomatrix Consultants, Inc., was "Earthquake Ground Motion Hazard Assessment and UC Berkeley." Youngs described current practices in probabilistic and deterministic ground motion assessment and discussed the application of these approaches in the special circumstances of the UC Berkeley campus. The campus is intersected by the northern portion of the Hayward fault, which, because of its frequent return period and location in relation to urban areas, is currently considered one of the most dangerous faults in the world.
UC buildings were again the topic in the March seminar. Guest speaker Dominic Kelly, of Degenkolb Engineers, spoke on "Barrows Hall, UC Berkeley Seismic Corrections." Kelly presented the evaluation results and strengthening scheme being proposed for this eight-story reinforced concrete campus structure. The building is located less than one-half mile from the Hayward fault. Particularly challenging aspects of this retrofit assignment are the client constraints of wanting to strengthen the building from the outside only so that the building can remain functional during construction, and to maintain the existing window layout.
The last seminar in the spring semester series was entitled "Estimating Losses at UC Berkeley," by Mary Comerio, Professor of Architecture, UC Berkeley. The April seminar summarized a pilot study that developed a methodology for assessing vulnerability, estimating losses, and evaluating the economic impact of those losses for the University campus. More specific than a regional description of loss, the vulnerability assessment includes the assembly of data in six key areas: (1) soil conditions, (2) infrastructure conditions, (3) structural conditions of buildings, (4) nonstructural conditions of buildings, (5) space use of buildings, and (6) occupants of buildings. The loss estimate includes an assessment of repair and replacement costs and downtimes for buildings. These are then built into an economic evaluation of the impact of closure or reduced operations on the local economy, on research, and on human capital. At the University of California, Berkeley, conservative cost estimates for repairs ranged from $600 million to $2.6 billion for different magnitude "credible" earthquakes, assuming only buildings with 60 percent structural damage would be replaced. In an M 7.0 earthquake on the Hayward fault, 4060 percent of the campus space would need more than 20 months for repair. If the university were forced to close for a year, the aggregate losses to the local economy reach $800 million in gross sales annually. In addition, for every student that stays in California to work following graduation, the contribution to the state's GDP is about $1 million in present dollars. The report is now published on the Internet at http://www-iurd.ced.berkeley.edu/pub/disaster-resistant.pdf.
The PEER-EERI series was well attended, and the seminars are expected to continue in the fall semester.