Experimental Study of All-Steel Buckling Restrained Brace With Windowed Lateral Support Elements

The buckling restrained brace (BRB) that has been worldwide adopted as a structural control device possesses excellent energy dissipation mechanism and can overcome the disadvantages of the traditional brace. However, the traditional BRB is a fully close design, it is therefore impossible to inspect the condition of the internal components during manufacturing and after earthquakes. This study proposed an all-steel buckling restrained brace with windowed lateral support elements that allow inspecting the internal condition of the BRB. We also studied the optimization in selecting the sizes and positions of the windows in the internal components without affecting its strength to provide an economically feasible all-steel BRB that is convenient for manufacturing and installation and meets the rigorous testing protocols. The all-steel BRB consists of the steel core, lateral support and constraining elements. In this study, scaled all-steel BRBs were tested under cyclic loadings by using an MTS 250 kN test machine. Test results showed that the mechanical behavior of the BRB with windows on the sides of lateral support elements is stable and that damage always occurred at the energy dissipation sections after low cycle fatigue tests. The difference between tensile and compressive forces was small under identical strain, and the accumulated inelastic deformation exceeded the requirement of test protocols. These test results confirm that the windows opened on the proposed BRB have insignificant effects on the strength of the device and that the proposed device meets the design requirement and is thus considered as a stable energy dissipative apparatus.