This report investigates the seismic performance of a reinforced concrete
bridge with prestressed hollow core piles. Both nonlinear static and nonlinear dynamic analyses were carried out. A three- dimensional “spine” model of the bridge was developed using SAP2000, including modeling of the bridge bearings, expansions joints, and soil-structure interaction. The effect of foundation soil flexibility was examined by running analyses on three different soil types and comparing the results.
The dynamic nonlinear response of the bridge was investigated by using three ground motions with different return periods. The nonlinear static response of the bridge was investigated using different variants of capacity spectrum methods. Nonlinear static analysis provided poor results compared to nonlinear dynamic analysis, due to higher mode effects. Results of both nonlinear static and dynamic analyses showed that the piles fail in a brittle fashion under seismic loading. Using results from 3D finite element analysis of the piles and pile-crossbeam connection, a more advanced spine model was created. The pile-crossbeam connection improved the strength of the bridge.