Finite-Element Analyses of Mechanically Stabilized Earth Walls Subjected to Midlevel Seismic Loads

Abstract

The objective is to examine the performance of specific detailing components of mechanically stabilized Earth (MSE) walls when subjected to midlevel seismic excitations, such as those expected in the State of Colorado. The motivation for this study is the elevated peak ground accelerations mandated by the 2007 4th Edition of AASHTO LRFD bridge design specifications. According to this revision, highway-related projects must be designed for an elevated 1,000-year return period earthquake, as opposed to the earlier editions’ 500-year return period earthquake. Finite-element analyses are performed using LS-DYNA to examine the displacement-based, dynamic behavior of individual MSE wall components, such as geogrid reinforcement and wall facings. Walls at two heights, 4.57 m (15.0 ft) and 9.14 m (30.0 ft), with two types of facings (modular block and segmental panel walls), reinforced using geogrids, are modeled based on the Colorado Department of Transportation drawings. These walls are subjected to three synthetic earthquake motions generated by the USGS 2002 deaggregation tool for three sites spread across the geographical extent of the State of Colorado. The results show that typical MSE walls perform well with respect to connection details when subjected to midlevel seismic loads.