Experimental study on horizontal low-cycle loading of high-strength concrete medium high shear wall with cold-formed steel braces

Abstract

This study presents the findings from experimental tests conducted on four medium-high shear walls with a shear span ratio of 1.8. The focus of the study is to investigate the effect of different types of cold-formed steel diagonal braces on the seismic performance of the shear walls. The specimens were subjected to horizontal low-cycle loading to observe their failure behavior, including cracking load, ultimate displacement, yield load, and ultimate load. Additionally, a comparative analysis of the stress distribution in the cold-formed steel braces, braces with different steel ratios but of the same type, and braces with the same steel ratio but of different types, was conducted. The research findings indicated that the inclusion of an appropriate amount of cold-formed steel braces with an appropriate steel ratio significantly improved the ultimate displacement and shear stiffness of the structures. The cold-formed steel braces effectively restrained crack development and prevent structural collapse after failure. However, it was observed that the lattice-type braces failed to confine the internal concrete to form a compressed concrete strut capable of resisting both shear and bending moment simultaneously. The addition of cold-formed steel braces was found to be advantageous in improving the shear stiffness of the specimens. In particular, the cold-formed angle steel braces in SRHCW-2 were more effective in enhancing the shear stiffness compared to the lattice-type cold-formed steel braces in SRHCW-3. Moreover, an increase in the steel brace ratio on top of the lattice-type cold-formed steel braces in SRHCW-3, as observed in SRHCW-4, contributed to a certain improvement in the structural shear stiffness.