Experimental and finite element study of high-strength steel framed-tube structures with replaceable shear links under cyclic loading

Abstract

Deep beams with small span-to-depth ratios in conventional steel framed-tube structures (SFTSs) cannot develop sufficient plastic behaviour at the beam ends, leading to poor ductility and energy-dissipating ability. High-strength steel framed-tube structures with replaceable shear links (HSSFT-RSLs) were developed to enhance the seismic performance of SFTSs and design a resilient structural system. Shear links using conventional mild steel were incorporated in the mid-span of the deep beams with end-plate connections to offer seismic energy dissipation and easy replaceability, while the remaining members using high-strength steel were maintained as essentially elastic. The seismic performance of HSSFT-RSLs and influences of the slab on hysteretic responses was explored using two 2/3-scale sub-structure specimens with sustained cyclic loading. Ductile failure of the link was observed while other members were still in the elastic range, which indicated a stable hysteretic response and excellent seismic performance. The slab slightly increased the initial elastic stiffness and had limited effect on the strength and stiffness in the plastic stage. The acceptable residual story drift θre that permitted the new links to be easily installed was 0.40%. Furthermore, the experimental responses of both specimens were accurately predicted via detailed finite element models developed in ABAQUS. A parametric analysis was conducted to determine the effects of link length on seismic performance. The results demonstrated that HSSFT-RSLs with short links limited to 1.13 Mp/Vp exhibited excellent seismic performance.