Hysteretic performance of inverted-V patterned BRB systems considering vertical pre-compression effects

Buckling-restrained braces (BRBs) could be installed in pares in high-rise frames or long-span structures, forming inverted-V patterned BRB systems, and the pre-compression effects are inevitably introduced into the BRB systems due to the vertical loads transmitted from upper structures. This paper presents the investigations on hysteretic performances of the inverted-V patterned BRB systems subjected to lateral cyclic loadings and vertical pre-compression. First, a parametric study via finite element (FE) analyses is conducted, considering the parameters including: pre-compression factors, vertical translational rigidity ratios, angles of the BRB systems and material properties of the BRB cores. According to the FE results, design recommendations are provided for practical designs of the BRB system and each individual BRB member. Then, based on the evaluation of the vertical and horizontal loading effects applied to the roof of a long-span structure equipped with the BRB system, formulas are proposed for designing of the long-span roof subjected to pre-compression as well as lateral earthquake effects. Finally, design procedures for the BRB system and the long-span roof are provided, which are further demonstrated by a practical design example.