Seismic Response of Reinforced Soil Retaining Walls: Is PGA-Based Design Adequate?

Abstract

Current seismic design approaches for reinforced soil retaining walls and slopes are primarily based on the peak ground acceleration (PGA) and neglect other important ground motion characteristics. As a continuation of an earlier study, dynamic response of a segmental (modular block) retaining wall subjected to different ground motions is investigated. A numerical simulation approach is used to examine the influence of ground motion characteristics other than the PGA on the seismic response of the reinforced soil wall. A total of 19 recorded ground motions and 2 variable-amplitude harmonic waves were used as the input acceleration. All input motions were scaled to a PGA value of 0.15g in order to isolate the influence of other strong ground motion parameters including predominant frequency, duration and intensity. Results of the study demonstrate the extent to which input ground motions with the same PGA values can result in different wall responses. It is concluded that current seismic design guidelines for reinforced soil structures need to be revised to include important influences of other ground motion characteristics in order to enhance the safety and economy of these structures.