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

Abstract

Hinged 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.

Precast concrete column base with replaceable energy dissipation connectors: Quasi‐static tests and numerical research

“…A Nonlinear Beam Column element with a length of only 0.1 mm is added at the upper end of the REDC on each side. Hysteretic material is employed to represent the repeated opening and closing of the interface between the upper concrete segment and the square steel tube 38 . In this case, the element has a large axial stiffness in compression, while the constitutive model of the Hysteretic material can be simplified to a double broken line in tension, of which the second axial stiffness is several times larger than the first axial stiffness.…”

“…Hysteretic material is employed to represent the repeated opening and closing of the interface between the upper concrete segment and the square steel tube. 38 In this case, the element has a large axial stiffness in compression, while the constitutive model of the Hysteretic material can be simplified to a double broken line in tension, of which the second axial stiffness is several times larger than the first axial stiffness. Both the first and second stiffnesses in tension are significantly smaller than the axial stiffness in compression.…”