EERI-UCI Chapter Seminar: Evaluating & Upgrading the Seismic Performance of Older Tall Buildings

The seismic performance of new tall buildings located in regions of high seismic hazard has been recently investigated by many, including the Pacific Earthquake Engineering Research (PEER) Center under its Tall Buildings Initiative (TBI) program. The Tall Building Initiative has now expanded to assess the seismic performance of existing tall buildings. Buildings being considered are 20 stories or more in height, and constructed on the West Coast of the U.S. between about 1960 and 1990. During this period, several hundred tall buildings were constructed in California, but earthquake-resistant design procedures were not fully developed. From these structures, a 35-story steel building, designed in 1968, and having representative details from that period, was selected for evaluation. In this presentation, results from three-dimensional nonlinear analysis models developed to assess the   potential seismic performance of this structure are presented. Two earthquake   hazard levels are used for the evaluation carried out in conformance with ASCE 41 requirements and other guidelines. The multitude of archaic details used in these older buildings provides a number of analysis and evaluation challenges. The structural analysis results are interpreted to assess the impact of suspected   deficiencies on seismic response, and the ability of different evaluation guidelines, numerical models and analysis methods to identify seismic vulnerabilities. With this understanding, retrofit strategies based on the use of fluid viscous dampers are explored. Recommendations for further research are offered. 

BIO: Steve Mahin is professor of structural engineering, and specializes in the design and analysis of structural systems to resist the effects of   potentially damaging earthquakes.  He work focuses on conceptual, analytical and experimental aspects of earthquake engineering.  He has carried out pioneering work in the development of   hybrid simulation methods, and has made major innovations related to seismic design of buildings, bridges, offshore structures, and industrial facilities. Today his work focuses on development of new types of resilient structures that are resistant to damage in   severe earthquakes, high performance computer simulation, and the effects of earthquakes, tsunami and other natural hazards on institutions and communities. He has more than 500 technical publications, and has been honored by the American Society of Civil Engineering by the Norman Medal, the Walter Huber Civil Engineering Research Prize, and election to the Offshore Technology Hall of Fame.  His accomplishments have been acknowledged by the Lifetime Achievement Award and Special Educators Achievement Award by the American Institute of Steel Construction.