Location

San Diego, California

Session Start Date

3-26-2001

Session End Date

3-31-2001

Abstract

Refuge accelerogram, 1987 Superstition Hills, CA; and the Kushiro Port station, 1993 Kushiro-Oki, Japan, among others. To understand the nature of these nonlinear effects, we have developed a model of nonlinear soil dynamics that includes nonlinear effects such as anelasticity, hysteretic behavior and cyclic degradation due to pore water pressure. The hysteresis behavior is given by the Generalized Masing rules. This new formulation has a functional representation and it includes the Cundall-Pyke hypothesis and Masing original formulation as special cases. It also provides a mean to quantify anelastic damping as a function of the stress-strain loop. Using the in situ observations from the Gamer Valley downhole seismographic array (GVDSA), we have modeled scenarios of ground motions at the surface for this site. The simulations show amplitude reduction as well as the shift of the fundamental frequency to lower frequencies as observed on vertical arrays. The synthetic accelerograms show the development of intermittent behavior-high frequency peaks riding on low frequency carrier-as observed in the acceleration records mentioned above. Comparisons between the nonlinear model predictions and those computed with the equivalent linear model demonstrate that the latter model fails to capture essential manifestations of nonlinear soil response.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-26-2001

Document Version

Final Version

Rights

© 2001 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 26th, 12:00 AM Mar 31st, 12:00 AM

New Observations and Methods for Modeling Nonlinear Site Response

San Diego, California

Refuge accelerogram, 1987 Superstition Hills, CA; and the Kushiro Port station, 1993 Kushiro-Oki, Japan, among others. To understand the nature of these nonlinear effects, we have developed a model of nonlinear soil dynamics that includes nonlinear effects such as anelasticity, hysteretic behavior and cyclic degradation due to pore water pressure. The hysteresis behavior is given by the Generalized Masing rules. This new formulation has a functional representation and it includes the Cundall-Pyke hypothesis and Masing original formulation as special cases. It also provides a mean to quantify anelastic damping as a function of the stress-strain loop. Using the in situ observations from the Gamer Valley downhole seismographic array (GVDSA), we have modeled scenarios of ground motions at the surface for this site. The simulations show amplitude reduction as well as the shift of the fundamental frequency to lower frequencies as observed on vertical arrays. The synthetic accelerograms show the development of intermittent behavior-high frequency peaks riding on low frequency carrier-as observed in the acceleration records mentioned above. Comparisons between the nonlinear model predictions and those computed with the equivalent linear model demonstrate that the latter model fails to capture essential manifestations of nonlinear soil response.