Cyclic performance of Y-braced steel frames equipped with a block slit damper

This paper investigates the cyclic performance of Y-braced steel frames (YSFs) equipped with a block slit damper (YSF-BSD). On the basis of the validation of an existing test on a Y-braced steel frame, the finite element (FE) model of YSF-BSD was developed. Then, parametric analyses are conducted to analyse the effects of the material strength, height-to-width ratio, height-to-thickness ratio, number and section shrinkage ratio of steel strips on the seismic performance and stiffness distributions of YSF-BSDs. The results show that (1) the ductility of YSF-BSD increases by 59.57% compared with that of conventional YSF, but the lateral loading capacity decreases by approximately 3.26%; (2) according to the parametric analysis results, the number of steel strips is suggested to be 4~5, the height-width ratio is 3~3.6, the height-thickness ratio should be larger than 3.3, and the section shrinkage ratio of steel strips should be 0.4~0.5; (3) a theoretical method is developed to determine the lateral stiffness distributions of YSF and BSDs, and the maximum error is less than 19.49%, most of which are less than 10%, and the lateral stiffness ratio of BSD to YSF is suggested to be 10~15 considering the ductility and deformation capacity of YSF-BSD.