Dynamic analysis of a multi-span simply supported prestressed concrete bridge with restrainers and seismic isolation devices

Abstract

The Nonlinear F.E. code Structural Analysis Program (SAP) in which the primary nonlinear characteristics of bearings, impact elements and steel restrainer cables considered herein in order to investigate the dynamic analysis of a multi-span simply supported MSSS prestressed concrete bridge, equipped with steel restrainer cables and Lead Rubber Bearings LRB devices including Soil Structure Interaction (SSI) effects. A MSSS bridge with restrainer cables and lead rubber bearings at the two abutments and intermediate bents located in North Algeria is selected according to RPOA for seismic design category 1 is considered in this study.  A detailed 3D nonlinear analytical model of study bridge subjected to three components identical seismic excitation including pounding elements, restrainer cables and bearing devices at expansion joints is developed. The nonlinear characteristics of theses boundary elements are represented by bilinear hysteretic models. Under strong seismic excitations, the large longitudinal displacements result the collision between bridge decks or even unseating of these decks at expansion joints of MSSS bridge. Finally, the study reveals among others that in order to prevent deck unseating resulting from restrainer failures and subsequent bridge collapse, particular attention should also be given to proper design of nonlinear characteristics of restrainers and bearing devices.