Cyclic behavior of high-strength steel framed-tube structures with bolted replaceable shear links

Abstract

Although the use of steel framed-tube structures (SFTSs) under intense earthquakes loads helps to prevent fatalities, the plastic hinges at the ends of spandrel beams cannot properly developed due to low clear span-to-depth ratios, resulting in poor ductility and recoverability. To address this problem, high-strength steel framed-tube structures with replaceable shear links (HSS-FTS-RSLs) were proposed, which combine the advantages of replaceable shear links and high-strength steel (HSS). This paper presents an experimental research program including three 2/3-scale single-story single-span sub-structure specimens with three types of spandrel beam-to-link connections: bolted end-plate connection, bolted web connection, and bolted splice-plate connection. The global seismic response and replaceability of the specimens were evaluated. Nonlinear finite element models of the specimens were established and validated with the experimental results. Test results demonstrated that the three specimens developed the expected ductile failure of the shear links while the spandrel beams and columns were damage-free, showing excellent energy dissipation and deformation abilities. The usage of HSS effectively maintained the structural components in essentially linear elastic range. The specimen with bolted end-plate connection exhibited a stable hysteretic response and high resistance. This connection type possesses reliable force transmission, convenient construction, no-slippage property, and the shortest replacement time. The connection rotation as a result of bolt slipping and bolt bearing significantly contributed to the total shear link rotation for the specimens with bolted web connection and bolted splice-plate connection. This led to the increased deformation ability and ductility as well as the pinching of hysteretic loops. Post-earthquake recoverability can be achieved as expected. The acceptable residual story drifts θre that allow for easy replacement of the shear links were 0.41%, 0.31%, and 0.42% corresponding to the specimen with bolted end-plate connection, bolted web connection and bolted splice-plate connection, respectively. The detailed finite element models of the test specimens accurately predicted the experimental behavior.