Cyclic tests of unbonded steel plate brace encased in steel–concrete composite panel

Abstract

Cyclic loading tests for the panel buckling-restrained brace (panel BRB) comprising an unbonded steel plate brace encased in a novel type profiled steel sheet–concrete composite panel were carried out to mainly investigate the effects of construction details of profiled steel sheets and perforated steel channels on the hysteretic behavior of the panel BRBs. Two loading stages, including increasing and constant amplitudes of horizontal displacement in the first and the second stages respectively, were used for six panel BRB specimens. Tests reveal that the perforated channels can prevent the composite panels from failure by punching shear. When stiffening ribs of profiled sheets were installed parallel to the axis of the brace, the composite panels remained intact in general after two loading stages. When the stiffening ribs of profiled sheets were installed in the horizontal or vertical direction, the specimens in which welds were used for the grooves of profiled sheets near the brace can also prevent panels from failure in the two loading stages, and bending failure of panels occurred in the first loading stage for the specimens without welds for the grooves of profiled sheets. The specimens, in which failure of panels was avoided, achieved great ductility and energy dissipation capacity before tensile fracture of steel braces occurred. Due to strain hardening and frictional action, the ultimate axial compressive strength of each specimen significantly exceeds its yield strength.