型钢混凝土异形柱受剪机理及承载力计算

为研究型钢混凝土(SRC)异形柱的抗震性能,对17个型钢混凝土异形柱试件采用"建研式"加载装置进行低周反复荷载试验,观察了不同配钢形式的SRC异形柱的受力过程和破坏形态。试验表明SRC异形柱的破坏形态有剪切斜压破坏、剪切粘结破坏、剪弯破坏和弯曲破坏;分析了SRC异形柱的破坏机理和特点,给出了荷载-位移滞回曲线和荷载-应变滞回曲线;分别推导了各种配钢形式的SRC异形柱在正向荷载(沿工程轴)以及斜向荷载作用下发生剪切斜压破坏和剪切粘结破坏时的受剪承载力计算公式,计算结果与试验实测值吻合较好。理论分析和试验结果表明:异形柱中的翼缘对构件的抗剪强度有提高作用,提高的程度与荷载作用方向和柱的肢长肢厚比有关,但在肢长肢厚比一定的前提下与肢厚的改变无关。T、L形截面柱的斜向抗剪强度大于正向加载抗剪强度,而十字形截面柱的斜向抗剪强度小于正向加载抗剪强度。

Shear mechanism and capacity calculation of steel reinforced concrete special-shaped columns

According to the experimental research on 17 specimens of steel reinforced concrete special-shaped columns under reversed cyclic loading,the failure process and patterns were observed.The failure characteristics and mechanism of SRC special-shaped columns are analyzed.It indicates that 4 types of failure patterns can be seen from the test specimens,including shear compression failure,shear-bond failure,shear-bending failure and bending failure.The loading-displacement hysteretic curves and loading-strain hysteretic curves are presented.Based on the failure characteristics and mechanism derived from test,the formulas for calculating ultimate shear capacity of different SRC special-shaped columns are derived under horizontal axis and oblique loading.The calculating results are in good agreement with those of tests.It is shown that flanges in SRC special-shaped columns can enhance the shear capacity.The degree of enhancement is related with loading direction and length to width ratio of column branches,but is irrelerant to width of branches when the length to width ratio is fixed.Shear capacity of T、L shaped columns under oblique loading are larger than that under horizontal axis loading,whereas the shear capacity of cruciform columns under oblique loading are less than that under horizontal axis loading.