Experimental Evaluation of Ductility of Bracing Members

Abstract

AbstractIn earthquake‐prone region, concentrically braced frames (CBFs) are used as lateral load resistance systems and prevents damage in structures. Special concentrically braced frames (SCBFs) are special type of CBFs system which is designed for higher level of displacement ductility and energy dissipation. In case of SCBF system, the connections are designed to undergo inelasticity which helps in dissipating the energy of the system. Two types of the connections that are used in the SCBF system are out‐of‐plane buckling (OOPB) connection and in‐plane buckling (IPB) connection. The latter is a newly developed connection for the SCBF system to prevent out‐of‐plane buckling of the braces which minimizes the damage of the non‐structural components of the building. In the present study, a state‐of‐the‐art comparison of the IPB and OOPB brace system were done keeping slenderness ratio and compactness ratio constant. Large‐scale tests were conducted on the two type of connections. Elliptical clearance of eight‐time the thickness of the gusset plate was used for the OOPB braced system. Linear clearance of three times the thickness of the knife plate was used for the IPB braced system. The parameters that were compared to measure the efficiency of the connections were displacement ductility, cumulative energy ductility and failure mechanism. It is found that the OOPB brace system performs better as compared to the IPB brace system keeping all other parameters constant. The reasons for the poor performance of the IPB brace system were discussed.