Direct Displacement-Based Seismic Retrofit of a 2D Concrete Frame Using Buckling Restrained Braces

This study seeks to upgrade a five-story concrete frame building that had been seriously damaged in the 5.12 Wenchuan earthquake using direct displacement-based design (DDBD) method and buckling restrained braces (BRBs). DDBD is a state-of-the-art performance-based seismic design method suitable for multi-story concrete frame buildings. BRBs are newly emerged assembled structural elements with properties similar to metal dampers, which are compatible with DDBD. These concepts are integrated in this work to showcase the performance-oriented seismic retrofit, where BRB properties are quantitatively determined and allocated. The analyses were based on static and dynamic nonlinear procedures. It is shown that the proposed DDBD method is effective to make full use of the unique characteristics of the BRBs, so that the retrofit members can be designed and arranged in an optimal way to meet preset displacement objectives.