04-27-2014, 08:22 AM
Experimental and Analytical Study of the Seismic Performance of Retaining Structures
Author: Linda Al Atik and Nicholas Sitar University of California, Berkeley | Size: 5.2 MB | Format: PDF | Quality: Unspecified | Publisher: PACIFIC EARTHQUAKE ENGINEERING RESEARCH CENTER | Year: 2009 | pages: 295
Recent changes in codes and improved understanding of strong ground motions have led increased demands in the seismic design of retaining structures. Correspondingly, the dynamic loads computed using currently available design procedures significantly exceed loads used the design of most of the existing retaining structures, suggesting that they may have significantly underdesigned. Field evidence from recent major earthquakes fails to show significant problems with the performance of retaining structures designed for static pressures only. In view of this, an experimental and analytical study of seismic earth pressures
on cantilever retaining structures was performed to address the apparent discrepancy between
theory and actual performance. Two sets of dynamic centrifuge model experiments were performed to evaluate magnitude and distribution of seismically induced lateral earth pressures on retaining structures and to study the seismic response of retaining wall–backfill systems. Two U-shaped cantilever retaining structures, one flexible and one stiff, were used in each experiment to model prototype structures representative of retaining-wall designs currently under consideration by the Bay Rapid Transit (BART) and the Valley Transportation Authority (VTA). Dry medium-dense at 61% and 72% relative density was used as backfill. The results obtained from the centrifuge experiments were used to develop and calibrate a two-dimensional (2-D) nonlinear finite element (FE) model built on the OpenSees platform. The finite element model was used to further study
the seismic response of retaining wall–backfill systems and to evaluate the ability of numerical
modeling in capturing the essential features of the seismic response observed in the centrifuge
experiments.
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