芯钢管增强的聚氯乙烯碳纤维复材管混凝土柱与混凝土梁连接节点的应力-应变关系

A STRESS-STRAIN RELATION OF JOINTS CONNECTING CONCRETE-FILLED PVC TUBE COLUMNS WITH CORE STEEL TUBES WRAPPED WITH CFRP STRIPS AND REINFORCED CONNCRETE BEAMS

通过对9个芯钢管连接的聚氯乙烯-碳纤维增强树脂(PVC-CFRP)管混凝土柱-钢筋混凝土梁节点轴压试验,对试件的破坏形态和应力-应变曲线进行了研究,探析了节点高度、芯钢管长度、芯钢管含钢率和节点环箍配箍率的影响。试验结果表明:节点区混凝土发生压溃破坏,而PVC-CFRP管混凝土柱未发生破坏;当节点区混凝土的拉应变达到极限拉应变时,节点应力-应变关系曲线偏离线性增长;随着节点环箍配箍率、芯钢管含钢率的增大以及节点高度的减小,应力-应变关系曲线斜率增大。基于Mander模型,建立了节点核心区应力-应变关系模型,模型计算值与试验值吻合较好。

Axial compression tests for 9 joints of PVC tube columns with core steel tubes wrapped with CFRP strips and reinforced conncrete beams were conducted, so as to study their failure modes and stress-strain relations, the effects of joint height, the length of core steel tubes, the steel proportions of core steel tubes, and the stirrup ratios of joints were studied. The experimental results showed that the concrete of joint zones was crushed and destroyed, and the PVC-CFRP tubular confined concrete column was not damaged. When the tensile strain of the joint concrete reached the ultimate tensile strain, the stress-strain curves of the joints deviated from linear growth. The gradients of the stress-strain curves increased with the increase of the stirrup ratios in joints and the steel proportion of core steel tubes increased or with the decrease of the joint height. Based on Mander’s model, an accurate model for estimating the stress-strain relations of the joints was constructed, and it agreed well with test data.