Pushover Analysis of I-5 RAVENNA Bridge

Nonlinear pushover analysis is a powerful tool for evaluating the inelastic seismic behavior of structures. This paper presents a detailed seismic analysis of a complex bridge. The I-5 Ravenna Bridge was assessed through nonlinear pushover analyses that highlights many important issues of bridges constructed on hollow core prestressed concrete piles. A three dimensional finite element analysis of the bridge have been carried out including modeling of the bridge bearings, expansions joints, and soil-structure interaction. The nonlinear response of the bridge was investigated from the first pier hinging to the inelastic equilibrium condition using three different response spectrums representing ground motions with different return periods. The effects on the seismic demand due to period lengthening and damping increase produced by structural deterioration were evaluated. The effects of three different soils on the bridge performance were investigated as well. Using dense sand increased the stiffness of the system and the ductility capacity. In addition, change the soil type has insignificant effect on the post-yielding stiffness of the bridge.