考虑翼缘影响的异形柱框架节点抗裂性能分析

在钢筋混凝土异形柱框架节点受力分析的基础上,应用弹性理论推导出考虑翼缘尺寸影响的节点抗裂承载力计算公式,并给出了节点核心区截面有效验算宽度、截面有效高度的表达式.另外,对4个异形柱框架节点进行了低周反复荷载作用下受力性能试验研究,分析了异形柱节点内箍筋应变随荷载变化情况.试验结果表明:节点内箍筋的应变在节点开裂前较小,计算异形柱节点开裂承载力时,可以不考虑其影响;当节点开裂后,箍筋应变突然增大.该荷载为节点核心区的开裂承载力.最后,将提出公式的计算结果与试验结果进行对比,表明该公式具有较好的适用性.

Crack resistance of RC joints with specially shaped columns considering the effect of flange length

According to the mechanical analysis of reinforced concrete (RC) joint with specially-shaped column, the formula of crack resistance considering the effect of flange length was derived on the basis of the elasticity theory, and the expressions for calculating the frame joint core effective height and effective width were presented. Furthermore, four RC joints with specially-shaped columns were tested under low cyclic loading to investigate the mechanical behavior, and the development of the stirrup strain in the joint was analyzed. Test results showed that the stirrup strain in the joint was small before the joint cracking, which can be ignored when calculating the crack resistance. While at the instant of joint cracking, the stirrup strain increased abruptly with the applied load corresponding to the crack resistance. Finally, the calculated results predicated by the proposed formula are compared with that by experiments, and indicate that the expression has good applicability.