Pseudo‐dynamic and quasi‐static testing of hinged truss with all‐steel buckling‐restrained braces at base

Abstract

AbstractHinged truss with buckling‐restrained braces at base (HTBB) is composed of a rocking steel braced frame system and two replaceable all‐steel buckling‐restrained braces (BRBs) installed symmetrically on both sides at the bottom of the rocking steel braced frame. BRBs are used as hysteretic energy‐dissipating devices and damage is concentrated in BRBs. The rocking steel braced frame remains in an elastic state to control the deformation mode of the structure. Pseudodynamic testing and quasi‐static testing were conducted on a 1/3‐scale HTBB test specimen to investigate its seismic performance. The test program also includes the retrofitting process and replacement process. Pseudodynamic testing revealed that the HTBB effectively controlled the deformation pattern. The quasi‐static cyclic testing demonstrated that the system behaved in a ductile and stable manner with no strength degradation, even up to 2.5% roof drift. The damage was concentrated in the BRBs, and no damage to the hinged truss was observed throughout the testing. The failure was governed by the fracture of the BRBs. The effectiveness of the displacement‐controlled retrofitting solutions was verified and the function of the test specimen can be restored by replacing the damaged BRBs, which indicated that HTBB belongs to a resilient structural system. Finally, a finite‐element model was developed to simulate the seismic response of the test specimen. Comparisons showed good agreement between the numerical results and the pseudodynamic test results.