On seismic response of stiff and flexible retaining structures

This paper presents an overview of the results of experimental and analytical studies of the seismic response of stiff and flexible retaining structures. These studies were motivated by very large dynamic forces in areas of high seismicity predicted by current seismic design methodologies based on the work of Okabe [3] and Mononobe and Matsuo [4]. However, there is no evidence of systematic failures of retaining structures in major earthquakes even when the ground accelerations clearly exceeded the design assumptions. The experimental program consisted of a series of geotechnical centrifuge model studies with different types of structures with cohesionless and cohesive backfill. Overall, the results of these studies show that the Mononobe-Okabe (M-O) method of analysis provides a reasonable upper bound for the response of stiff retaining structures and that flexible retaining structures experience loads significantly smaller than those predicted by this method. Moreover, for deep embedded structures the dynamic forces do not continue to increase with depth and gradually become a small fraction of the overall load on the walls.