Sensitivity of seismic response of pile?supported, multi?span viaduct bridges to interaction between soil?foundation and structural parameters

摘要

Soil-structure interaction (SSI) in pile-supported bridges coupled with non-linear behavior of the structural bridge elementsis a complex problem. A sub-structuring technique that accounted for the kinematic and inertial SSI effects and non-linearfinite element method (FEM) numerical model in the software SAP2000 were employed to investigate the response of a typical4-span continuous bridge in two orthogonal directions founded in five soil profiles belonging to AASHTO site classes Cand D. The FEM analysis results were disaggregated to delineate the effect of SSI and pier column inelasticity (PCI) on threeoutput quantities, i.e., bridge deck acceleration (A), bridge displacement (δ), and pier column shear force (V). Sensitivityanalysis, conducted using Morris method, ascertained the influence of SSI and PCI on the output quantities. It was revealedthat all three response quantities were more sensitive to PCI in both orthogonal directions in all soil profiles compared toSSI. However, sensitivity of the response quantities to SSI was significant in the transverse bridge direction in all but onesoil profile, which was explained through a lumped parameter model. Contrary to the current AASHTO code requirement,the inclusion of SSI for the design of pile-supported bridges in all seismic design categories (SDCs) is recommended forthe bridge typology studied herein.