New Hybrid Multi-Core Buckling-Restrained Brace Designs for Enhanced Seismic Performance

Abstract

AbstractThe configuration of ductile steel elements in a steel frame is fundamental to the structure’s performance under seismic ground motion. Hybrid solutions are being explored as an alternative to traditional structural systems to improve on their limitations. The hybrid concept is hinged on harnessing benefits from the varying characteristics of different designs or materials carefully combined into one ductile design to achieve a desirable response. Contemporary seismic-resistant design of steel braced frames is based on dissipating earthquake energy through significant inelastic deformation in the brace elements. Buckling-restrained braces (BRBs) are a type of concentrically braced system characterized by braces that yield equally both in tension and in compression, thus exhibiting superior energy dissipation capability. However, BRBs often display a low post-yield stiffness, and consequently large residual drifts after seismic events. One promising solution is to design a hybrid BRB, which includes multi material steel cores. The present research has two main objectives: to investigate the potential of different combinations of core plate materials, then followed by an explicit design of hybrid brace systems that can accommodate the complex deformation pattern of the multiple core plates. Results indicate that the post-yield behavior of hybrid BRBs is improved when a 350WT carbon steel is used in conjunction with another metal having low-yield and high strain-hardening behavior, such as stainless steels, some aluminum alloys, or other grades of carbon steels. Finally, the design process and the details of two hybrid BRB configurations are presented.