Structural evaluation of steel moment resisting frames upgraded with buckling restrained knee braces

In this study, the structural performance of three and six storey steel buildings accompanied with buckling restrained braces was evaluated. The buildings studied were regular in plan and had a typical 3 bay x 3 bay frame with plan dimensions of 14 m x 14 m. For this, two dimensional models for the buildings were created and then buckling restrained braces in knee configuration were installed above and/or below the beams of the frame system. The seismic response of the structures with and without buckling restrained knee braces was assessed through nonlinear static and dynamic analyses. Moreover, two different spectrum compatible earthquakes, namely, 1999 Hector Mine and 1999 Düzce, were used in the dynamic analyses. Analytical results indicated that the steel moment resisting frames with buckling restrained knee braces had greater lateral load carrying capacity and lower inter-storey displacement than the bare frames.