This paper presents a detailed seismic analysis of a complex bridge. The I-5 Ravenna Bridge was assessed through nonlinear dynamic and pushover analyses that highlight many important issues for bridges constructed on hollow-core prestressed concrete piles. A three dimensional finite element analysis of the bridge has been carried out, including modeling of the bridgebearings, expansion joints, and soil-structure interaction. The nonlinearresponse of the bridge was investigated from the first occurrence of pierhinging to the inelastic equilibrium condition using three different response spectra representing ground motions with different return periods. The effects on the seismic demand due to period lengthening and the damping increase produced by structural deterioration were evaluated. Different versions of the capacity spectrum method were investigated and the results were compared to those of the dynamic analysis. In general, the capacity spectrum method proposed in FEMA 440 gave the most accurate results. 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, changing the soil type has only an insignificant effect on the post-yielding stiffness of the bridge.
Samenvatting