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Performance-based assessment of a reinforced concrete bridge with bucking restrained braces

This study evaluates the potential advantages of using buckling restrained braces (BRBs) to seismically rehabilitate an existing bridge. These benefits may include an enhanced bridge performance, environmental sustainability and expedient replacement. A three-dimensional numerical model of a three-span reinforced concrete box girder bridge was developed in the software Opensees. The model includes soil-structure interaction effects and incorporates BRBs between bent columns to increase the bridge seismic performance. The performance of the BRB components is consistent with that obtained from experimental results carried out at the University of Utah. The BRB inelastic behavior is represented using the Menegotto-Pinto model, which can reproduce the combined isotropic and kinematic strain hardening properties of these components. Nonlinear time history analyses (THAs) are then performed to assess the seismic performance of the BRBs and the existing concrete columns. The structure is evaluated under several performance limit states using far-field records from FEMA P695, which are scaled to the maximum considered earthquake (MCE) level at the site. The proposed model in this study also considers 3D Incremental Dynamic Analyses (IDAs) to approximate bridge collapse as a function of the seismic intensity level. The results show that properly designed BRB components increase the bridge energy dissipation capacity, which increases the serviceability limit states. The IDA data also shows that the inclusion of BRBs reduces bridge damage during strong seismic events. A design procedure for BRB in reinforced concrete bridges is provided based on analyses results.

Author(s):

Yuandong Wang    
The University of Utah
United States

Luis Ibarra    
The University of Utah
United States