Performance of novel perforated double-core steel-plate assembled buckling-restrained braces

Abstract

This study proposed and evaluated a novel perforated double-core steel-plate assembled buckling-restrained brace (PDBRB). First, the mechanical properties of the PDBRB were theoretically derived to inform its design. Second, quasi-static tests were carried out on three PDBRB specimens with different configurations and one conventional perforated steel-plate assembled buckling-restrained brace (PBRB) specimen to comparatively evaluate the mechanical properties, energy dissipation performance, and optimal configuration of the PDBRB. Third, finite element analyses of the four test specimens were conducted to determine their stress distributions, equivalent plastic strains, and high-mode buckling deformation patterns. The following conclusions were drawn from the results of these investigations: 1) the novel PDBRB exhibited similar mechanical properties to those of the PBRB but with superior cumulative plastic deformation and energy dissipation capacity; 2) middle restraining plates were essential for the PDBRB, as when they were not present, the PDBRB exhibited a larger axial compressive force and compressive strength adjustment factor, fewer fatigue loading cycles, less total dissipated energy, and a smaller cumulative plastic deformation and equivalent visual damping ratio, especially when there was no gap between the two core plates; 3) The proposed design method can be used to accurately predict the mechanical properties of PDBRB; 4) the yielding process of the PDBRB began from the opening segments, neither the connecting nor transition segments yielded under a maximum displacement of 30 mm, and the maximum equivalent plastic strains in the PBRB and PDBRB with restraining plates were similar and considerably smaller than those in the PDBRBs without middle restraining plates; 5) under compression, a larger number of high-mode waves were generated in the core of the PDBRBs than in that of the PBRB. The deformed shapes of the two core plates of the PDBRB were mutually independent and dissimilar when middle restraining plates were provided but similar when these restraining plates were excluded regardless of whether a gap or unbonded material was provided between the core plates.