Effects of Nonlinear Soil-Structure Interaction on the Inelastic Seismic Demand of Pile-Supported Bridge Piers

Abstract eng:
The significance of the effects of soil-structure interaction (SSI) on the seismic performance of structures is not yet clearly understood. This is attributed to the complex nonlinear nature of SSI and the lack of sufficient statistical description of its effects on the seismic response of structures. In this regard, this paper presents a study on the effects of nonlinear SSI on the inelastic seismic demand of bridge piers by comparing the flexiblebase and fixed-base seismic demands of prototype pile-supported bridge piers. The prototype system comprised a common highway bridge pier supported on a pile group. The height of the pier and the thickness of the site soil layer were varied to provide first mode fixed-base structural periods of 0.3 to 2.0 s and first mode site periods (at low amplitude of motion) of 0.6, 1.0 and 2.0 s. An ensemble of 26 ground motions recorded on rock or stiff soil was selected and applied at the bottom of the soil layers. The numerical models for nonlinear dynamic analyses included the site soil, the foundation and the pier, and were developed with the commercial finite difference program FLAC. This paper discusses the effects of SSI on ductility and total displacement demands of the piers. It also investigates the accuracy of the nonlinear static pushover analysis for demand estimation of pile-supported bridge piers. It was observed that where SSI is significant, pushover analysis may overestimate the base shear of the piers and the global ductility factor may overestimate their ductility demand. KEYWORD:

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket