Extending the seismic life span of bridges. Analytical evaluation of retrofit measures

The purpose of this paper is to emphasize the evaluation of retrofit solutions for bridges including nonlinear base isolations combined with nonlinear restoring springs based on a newly developed computational platform for nonlinear analysis of bridge structures. The paper emphasizes the platform that allows for nonlinear representation of bridge structural components, isolation components, soil springs, expansion joint gaps and miscellaneous linear and nonlinear link elements. Furthermore, the paper shows the integration of the individual models in an overall structural system with complex loading for evaluation of bridge capacity and seismic demand using efficient numerical procedures. The evaluation of an 11-span bridge subjected to extremely severe ground shaking is shown as a case study for the aforementioned retrofit technique.