A Comparison Between the Performance of Moment Resisting Frames Having Conventional Braces with Moment Resisting Frames Having Buckling Restrained Braces

Conventional bracing systems have an essential weakness to tolerate lateral loads effectively.The bracing elements may buckle under large compressive axial forces before they can fulfill their role in the range of plastic material behavior. If by some means bracing elements are prevented to buckle, they will be able to endure compressive axial loads exceedingly. This increases the damping ability of the bracing system considerably. In this paper the performance of moment resisting frames combined with conventional bracing systems is compared with the moment resisting frames having buckling restrained braces. Structural models with 4, 8, 12 and 16 are considered. Seismic loading of models are proceeded according to Iranian code of instruction for seismic rehabilitation of existing buildings and Iranian standard of 2800-05. Design of steel elements is performed based on Iranian national building code-part 10. Pushover nonlinear analysis is employed to identify the performance level of models. In addition the performance of two considered systems is compared by the aid of nonlinear dynamic analysis using Northridge and Tabasaccelerograms.

Keywords:

performance , moment resisting frames combined with conventional bracing systems , moment resisting frames having buckling restrained braces , Pushover nonlinear analysis , nonlinear dynamic analysis