Design Implementation of Buckling Restrained Braces for Seismic Retrofitting of Reinforced Concrete Multi-Column Bridge Bents

摘要

The bridge seismic retrofit measure presented in this paper aims to concentrate all the inelastic demand and energy dissipation, during a moderate to large earthquake, in disposable elements while the main structure remains essentially elastic and its integrity is preserved. Buckling restrained brace (BRB) systems have been successfully implemented in buildings; however, their implementation in bridges has been limited. The design implementation of BRBs that is presented include the analysis of the overall behavior of the bridge under two seismic performance levels and outlines design options for the brace-to-concrete connection. A case study of a representative reinforced concrete bridge bent constructed in the 1950 to mid-1970 in the Pacific Northwest is presented in an effort to demonstrate the retrofit procedure for the transverse direction. This retrofit option provides an additional tool for bridge design professionals looking to comply with performance-based criteria used to assess typical retrofit options.