SEISMIC PERFORMANCE AND DAMAGE EVALUATION OF IRREGULAR STEEL JOINTS IN MODERN CHINESE TRADITIONAL-STYLE BUILDINGS WITH BLIND BOLTS

Abstract

Steel modern Chinese traditional-style buildings (MCTBs) commonly adopt fully welded connections. However, the use of circular hollow section (CHS) columns at beam-column joints, coupled with strict architectural aesthetic requirements, presents significant challenges for the application of conventional bolted connections. This issue represents a critical technical bottleneck that hinders the development of prefabricated construction in such buildings. To address this challenge, a novel prefabricated joint configuration based on blind bolt-T-stub assemblies was proposed. Four 1:2.6-scale specimens, including two single-beam column joints and two double-beam column joints, were fabricated and tested under low-cycle reversed loading to evaluate their seismic performance in terms of failure modes, hysteretic behavior, ductility, energy dissipation, and stiffness degradation. Furthermore, refined finite element (FEA) models were established to reproduce the experimental deformation patterns, stress distribution, and moment–rotation hysteresis behavior, including the relative slippage of the double-beam connectors. All specimens conformed to the strong-column weak-beam design principle, with damage primarily concentrated in the T-stub region. Compared to the single-beam column joints, the double-beam column joints demonstrated superior load-bearing capacity, enhanced energy dissipation, and greater safety redundancy. Moreover, increasing the T-stub thickness further improved the overall performance. Seismic damage was quantified using a modified Park-Ang damage model, confirming that the proposed prefabricated joint exhibits favorable seismic behavior and practical engineering applicability. The findings offer an effective structural solution for the industrialized seismic design of beam-column joints in steel MCTBs.