Dynamic performance of steel-reinforced concrete vertically irregular structures with various transfer connections

AbstractThe newly proposed partially embedded transfer connection (PETC) in steel-reinforced concrete vertically irregular structures has demonstrated superior performance in terms of static structural behavior and economic efficiency compared to conventional embedded connections (ECs). To evaluate the impact of transfer connection details on the dynamic performance of such structures, a shaking table test, complemented by finite element (FE) analysis, was conducted on a 1/6-scale model. The scaled structure consisted of a two-story steel frame connected at its base to the top of a three-storey reinforced concrete (RC) structure. Test results revealed that the structure utilizing PETC remained predominantly elastic under service-level earthquake conditions. Additionally, under bidirectional seismic excitations, the steel components exhibited notable amplification of acceleration and displacement responses at the transfer connection as seismic intensity increased. The effectiveness of PETC in ensuring structural safety was further validated by the measured inter-story drift ratios of the five-story building, which remained within codified limits. FE analysis demonstrated that structures incorporating PETC experienced significant reductions in roof displacement and acceleration compared to those with ECs, with peak reductions of up to 44.0 % and 57.0 %, respectively. Furthermore, the addition of steel braces to the steel frame effectively mitigated vertical stiffness irregularities within the structure, leading to decreased displacement and acceleration responses and alleviating adverse whipping effects.