Plastic hinge and damage mechanism of RC assembly column base joint with post pouring area

Abstract

Column base joint with post pouring area connected by grouted sleeves (PPCGS), which can solve the problems of poor controllability of grouting quality in the engineering application of traditional sleeves, is proposed in this paper. Based on the horizontal low-cycle reversed loading test results of six full-scale column base joints under axial pressure, the mechanics characteristic of plastic hinge, the length of equivalent plastic hinge, and the displacement ductility are mainly explored. The research results showed that the plastic hinge was formed above the sleeves in all precast column base joints, and the post pouring area of PPCGS column base joints can provide higher compressive strength, so it could protect the longitudinal rebar under the sleeve from premature buckling deformation, made the plastic hinge fully develop at the top of the sleeves. The ratio of the equivalent plastic hinge length to the section size of PPCGS column base joints decreases as the section size of column and the strength of the post pouring material increase. The average error between the calculated results and the test results of the displacement ductility coefficient of PPCGS column base joints is -3.93%, and the displacement ductility coefficient showed an increasing trend with the increase of the section size and the strength of post pouring material. In addition, a finite element analysis method for the PPCGS column base joint was verified through experimental results, and the influence law of post pouring height and tenon section size on the damage of column base joint was obtained through parametric analysis.