Seismic life-cycle cost evaluation of steel-braced frames: Comparing conventional BRBF with emerging SCVDF and HBF systems

Abstract

In the past two decades, various self-centering bracing systems have been developed to enhance structural seismic resilience. However, compared to conventional bracing systems, their high initial cost and lower efficiency in controlling peak floor accelerations have reduced their economic benefits and limited their application in engineering projects. Accordingly, the self-centering viscous energy-dissipative brace (SCVDB) and the hybrid bracing system (HB), the synergistic combination of the SCVDB and buckling-restrained brace (BRB), have emerged as innovative approaches with exceptional capabilities in passive control over peak floor acceleration demand. Despite their promise, a comprehensive understanding of the life-cycle economic benefits of structures equipped with these bracing systems remains limited. This study aims to comprehensively highlight the life-cycle economic benefits associated with self-centering viscous energy-dissipative braced frames (SCVDFs) and hybrid braced frames (HBFs) compared to traditional buckling-restrained braced frames (BRBFs) across various structural heights using the improved HAZUS assessment methodology. Focusing on 4-, 8-, and 12-story buildings designed with BRBFs, SCVDFs, and HBFs, each maintaining identical peak inter-story drift ratios, the research conducts dynamic analyses combined with Monte Carlo simulations. Critical parameters such as residual inter-story drift (RID) limits defined for demolition, initial construction costs of the SCVDBs, and discount rates are considered. The analyses reveal that the expected annual earthquake-induced loss (EAL) for mid- and high-rise structures is more sensitive to RID limits than those of low-rise structures. The SCVDFs and HBFs exhibit lower EAL than BRBFs, even without considering the demolition situation. The RID limit, initial construction cost of SCVDBs, and discount rates significantly influence the relative economic benefits of SCVDFs and HBFs compared to BRBFs. In most scenarios, HBFs demonstrate superior economic benefits over SCVDFs. The HBF effectively utilizes the synergistic effects of SCVDBs and BRBs, substantially lowering initial construction costs and achieving favorable economic benefits across various structural heights within the considered parameter range.