Experimental study on the cyclic behaviour of shear links made of BLY160 steel

摘要

The cyclic behaviour of shear links made of a new type of low-yield-point (LYP) steel BLY160 is intensively investigated. A total of twelve specimens are designed to evaluate the influence of material type, web compactness, link flange, web stiffeners, restraining ribs of the web panel and link length ratio on force transfer mechanism of shear links. Based on the analysis of the failure mode and process, hysteretic performance, strain distribution and development of test specimens, it is found that the excellent mechanical properties of the BLY160 steel have enabled the shear link to yield at a lower strength and reach an inelastic rotation capacity as large as 0.16 rad. Introducing the link flange and reducing the link length ratio can effectively improve the seismic performance of the shear link. Due to the strain-hardening phenomenon of BLY160 steel, the overstrength factors of shear links have reaches 1.70 to 2.02, and is gradually increasing with the reduction of link length ratio. The current design provisions can be applied to calculate the yield strength of shear links with a link length ratio smaller than 2.0. Except for the shear links with diagonal web stiffeners or composed of traditional steel, all the shear links have reached an equivalent damping coefficient exceeding 0.50. Finally, an isotropic-kinematic combined hardening restoring force model is proposed to simulate the cyclic behaviour of shear links made of BLY160 steel, the feasibility and accuracy is verified by comparing the predicted hysteretic curves and test results of shear links with different forms.