Jonathan P. Stewart, professor and chair of the civil and environmental engineering department at University of California, Los Angeles, was chosen as the 2018 recipient of the Bruce A. Bolt Medal, which is awarded jointly by the Seismological Society of America (SSA), the Consortium of Organizations for Strong-Motion Observation Systems (COSMOS) and the Earthquake Engineering Research Institute (EERI).
The Bolt Medal is awarded to recognize individuals worldwide whose accomplishments involve the promotion and use of strong-motion earthquake data and whose leadership in the transfer of scientific and engineering knowledge into practice or policy has led to improved seismic safety.
Stewart has made a number of significant contributions to earthquake engineering. His work on soil-structure interaction has resulted in empirically validated models for kinematic and inertial interaction effects on foundations and walls. His work on soil amplification has clarified the roles of linear and nonlinear response, the factors that affect them and uncertainty in site response estimates. His nonlinear amplification models have been incorporated into contemporary ground motion prediction equations and form the basis for how site effects are handled in current practice. He recognized seismic compression of fills and unsaturated soils as an important problem and developed procedures for estimating earthquake-induced settlement of such materials.
He has been an active participant in numerous post-earthquake field reconnaissance investigations, and has followed up on those investigations with research aimed at understanding observed performance of soil profiles, embankments and levees and soil-structure systems in the U.S., Italy, Greece, Turkey, Taiwan and Japan. He conceived of and is currently leading the development of the Next Generation Liquefaction (NGL) project, a major effort that will finally harmonize the data and model development process by which soil liquefaction hazard evaluation procedures are developed.
Stewart has put a great deal of effort into transferring the results of his research and the research of others into engineering practice. In addition to publishing clear and practical papers in the technical literature, he has been active in study groups and code committees. He has taken the lead in writing major reports on ground motion evaluation for performance-based design, analysis and mitigation of landslide hazards, performance of nonlinear site response analysis, performance- based design of tall buildings, soil-structure interaction for buildings and performance of hazard-consistent, one-dimensional ground response analysis. These reports are noteworthy for their combination of academic rigor and practical utility. He has served on and led code committees developing new site coefficients, nonlinear analysis procedures and seismic hazard maps for the United States.
Stewart is the current editor of Earthquake Spectra and former Chief Editor for the ASCE Journal of Geotechnical and Geoenvironmental Engineering. Previously, he was selected by SSA and EERI to deliver the 2016 William B. Joyner Lecture in recognition of his work on the characterization of earthquake ground motions for engineering applications, with special emphasis on site response effects. Past recognition of Dr. Stewart’s work has included the Huber Prize and Casagrande Awards from the American Society of Civil Engineers, a Fulbright Scholarship from the U.S. State Department, a National Science Foundation CAREER award, and the Distinguished Teaching Award from the UCLA Academic Senate.