Seismic evaluation of repaired multi-column bridge bent using static and dynamic analysis

Abstract

Abstract Simulation of the cyclic response of a structurally deficient as-built reinforced concrete three-column bridge bent is conducted. The bent had deficient seismic details and was previously tested under cyclic loads in the field; damage included concrete crushing and longitudinal steel buckling at the column ends. A fiber-based bridge bent model is developed in OpenSees which includes soil-structure interaction (SSI) using simplified springs. The in-situ test of the as-built bent is used to validate the model. Subsequently, the damaged bent is conceptually repaired with a carbon fiber-reinforced polymer (CFRP) enlarged column cross-section, denoted as “CFRP donut”, which includes a CFRP shell, headed steel bars, nonshrink concrete and a steel collar at the column bottom ends; CFRP composite jackets are employed above the CFRP donut to increase column shear and confinement. Design guidelines of the repair using a simplified strut-and-tie model (STM) are presented. A comparison of the as-built and repaired bridge bents under nonlinear static pushover analysis, incremental dynamic analysis (IDA), and fragility analysis using 22 far-field ground motions shows that the repair method is successful.