Department of Civil and Environmental Engineering

CEE Seminar

“Modeling and Simulation of Near-Fault Strong Ground Motions for Earthquake Engineering Applications”

Speaker: Dr. George P. Mavroeidis, Ph.D.

Thursday, April 15, 2004

10:30 a.m. – 11:30 am*

Tompkins Hall of Engineering, Dean’s Conference Room

*Followed by a Question & Answer Session

Abstract: Even though the destructive effect of the near-fault strong ground motions on long-period structures (e.g., long-span bridges, tall buildings, storage tanks) was originally recognized more than three decades ago, the lack of an adequate number of near-source ground motion records has hindered their thorough study. It is only recently that the gradually increasing number of recorded near-source time histories has enabled strong motion seismologists to better understand the character of the near-fault ground motions and earthquake engineers to start considering methods to incorporate near-source effects in engineering codes and design. This study aims at providing to earthquake engineers simple tools and techniques that enhance the physical understanding, characterization, proper parameterization, analytical modeling, and numerical simulation of near-fault ground motions for earthquake engineering applications. A simple analytical model is proposed for the representation of near-source ground motions that adequately describes the impulsive character of near-fault ground excitations both qualitatively and quantitatively. The model input parameters have an unambiguous physical interpretation and scale, to the extent possible, with physical parameters of the fault rupture. A simplified methodology, for generating realistic broadband near-fault ground motions that are adequate for engineering analysis and design, is outlined and applied. A comprehensive study of the elastic and inelastic response of the single-degree-of-freedom (SDOF) system subjected to near-fault ground motion excitations is also presented. As a key parameter of the ground motion model emerges the pulse duration that is used to normalize the abscissa (period-axis) of response spectra. Such normalization makes feasible the specification of design spectra and reduction factors appropriate for near-fault ground motions. The effect of fault rupture characteristics (i.e., slip, rupture velocity, state of stress) on near-fault ground motions is also investigated using a kinematic approach in an attempt to identify physical processes that lead to specific ground motion patterns. Finally, the primary characteristics of strain, rocking, and torsional components of ground motion in the near-fault region induced by seismic excitations are discussed and a simplified approach is presented for the description of the torsional component of the dynamic ground deformation field.

About the Speaker: Dr. George P. Mavroeidis is currently a Postdoctoral Research Associate at the State University of New York at Buffalo, where he obtained his Ph.D. in Civil Engineering with a specialization in Engineering Seismology and Earthquake Engineering. Dr. Mavroeidis obtained his M.S. in Civil Engineering from Rensselaer Polytechnic Institute in Troy, New York. Among his research interests includes Structural Dynamics, Structural Mechanics, and Geotechnical Engineering. He also has professional affiliations with the Seismological Society of America, the Earthquake Engineering Research Institute, the Technical Chamber of Greece, and the American Society of Civil Engineers.