Experimental Investigation on Seismic Behavior of Interior Joints with Abrupt Reduction in Beam and Column Section

摘要

According to the experimental investigation on four specimens of interior joints under low cyclic reversed loading, the failure process and failure patterns were obtained. The failure characteristics, mechanical behaviors of abnormal joints such as the load displacement hysteretic loops, rigidity deterioration and energy dissipation are analyzed. The experimental study was conducted that focused on the effect of joint core dimensions and hoop percentage on seismic behaviour of abnormal joints. Test results indicated that the first crack appeared in the minor core (determined by the low beam and the top column), and the final failure appeared in the large core (determined by the high beam and the bottom column). The critical crack load was quite nearly with the ultimate load of abnormal joints. The load displacement hysteretic loops of low beam and high beam are quite differently with each other, the hysteretic loops of all the high beams show a reversed S-shape exhibited sever pinching with little energy dissipation. On the contrary, those of the low beams show a hooked end shape with improved energy dissipation. Considering normal practice in a structural analysis to assume that the beam-column connection is rigid, the reinforcing details of the test specimen, which were designed under the guideline of current codes, can not preserve the structural integrity and satisfy the strong joint demand.