On the Seismic Performance of Hat Knee Bracing System in Low-Rise Multistory Steel Structures

Abstract

In this paper, the behavior and performance of a new type of bracing system called Hat Knee Bracing (HKB) is investigated in low-rise multistory steel structures. This novel form of resistant system, which provides reasonable stiffness in moderate earthquakes, consists of a V shaped knee member connected to mid span of the beam and the brace members. In this research work, the “FEMA P695 evaluation method” is utilized in order to explore the nonlinear behavior of the HKB frame, and quantification of three seismic performance factors: Response Modification Factor, Over-strength Factor, and Deflection Amplification Factor. The seismic response simulation of archetype frames is performed using the OpenSees software. The results of analyses reveal that the performance of the HKB is suitable under a rare earthquake and under moderate intense earthquakes the damages are mostly concentrated in knee members instead of the principal members such as beams and columns.