PEER Reports

The behavior of bridges subjected to recent moderate and large earthquakes has led to bridge design detailed for better seismic performance, particularly through wider bridge foundations to handle larger expected design forces. Foundation uplift, which is not employed in conventional bridge design, has been identified as an important mechanism, in conjunction with structural yielding and soil-structure interaction that may dissipate energy during earthquakes. Preventing uplift through wider foundations looks past the technical and economic feasibility of allowing foundation uplift during...

Extensive damage to buildings and infrastructure observed during past earthquakes resulting from the liquefaction of shallow saturated soil deposits underneath structures has demonstrated the necessity for further research in the area of liquefaction-induced ground movement effects. This study explores utilizing helical piles as a countermeasure to reduce liquefaction-induced foundation settlement and investigates their seismic performance in liquefiable grounds. Two large-scale shake table test series, one without any mitigation measures and one using helical piles, were conducted using...

Most industrial and nuclear facilities rely on reinforced concrete (RC) structural walls as their primary seismic lateral-force-resisting components. These walls commonly have an aspect ratio smaller than 0.5 and have a very high stiffness and strength. There is a significant uncertainty regarding the behavior of these walls under earthquake loading, their failure modes, and their expected strengths and deformation capacities. Hybrid simulation is an effective experimental method to examine these issues: it enables simulation of the seismic response of squat and thick shear walls without...

This report presents an update to the Chiou and Youngs [2008a] NGA model for the prediction of horizontal peak ground acceleration and 5%-damped pseudo spectral acceleration for earthquakes in active tectonic regions such as California. The update is based on analysis of the greatly expanded NGA-West2 strong motion database. The updated model contains minor adjustments to the functional form developed by Chiou and Youngs [2008a] related to style of faulting effect, hanging wall scaling, scaling with the depth to the top of rupture, the effect of sediment depth, and the inclusion of two...