Structures with Added Buckling Restrained Brace Elements

The number of high rise building has increased significantly as supporting infrastructure in many big cities in Indonesia. Most of the high rise buildings in Indonesia are constructed using reinforced concrete (r/c) moment resisting frame systems. However, due to the high seismicity of many of the regions of Indonesia, the use of moment resisting frames as single system, especially for tall buildings, are restricted. This structural system is in general quite flexible, and therefore excessive lateral drifts are experienced under seismic forces. In practice, adding buckling restrained brace (BRB) can be used to limit the lateral drift in high rise buildings. The objective of this paper is to present a study on the use of BRB elements in high rise r/c frame buildings to evaluate their seismic performance. In this paper, a 20 story office building located in a high seismicity region is modeled into two basic distinctions, i.e. building with BRB and without BRB. The adopted system of BRB is UBB (Unbonded Brace) type. The seismic response of the buildings is obtained by conducting non-linear time history analysis with seven scaled ground motions. Then, the performance of these buildings are evaluated and compared. Based on the findings, some recommendations are proposed for the use of BRB in the design of high rise r/c frame buildings located in regions with high seismicity.