方钢管约束型钢再生混凝土柱-钢梁节点抗震性能分析

基于非线性和再生混凝土损伤因子的塑性损伤本构，建立了外加强环全焊接刚性连接、外套管式端板连接半刚性连接以及顶底角钢全螺栓连接半刚性连接3种形式的方钢管约束型钢再生混凝土柱-钢梁节点有限元模型，分析了各模型的抗震性能。结果表明:在低周循环加载下，柱内含有支撑骨架且没有穿柱构件时，有利于提高节点域核心再生混凝土的整体性，受力简单；采用外套管约束节点域，核心再生混凝土的应力、应变较小，有利于再生混凝土耐久性的提高；在相同轴压比、梁柱线刚度比的情况下，外加强环全焊接刚性节点承载能力和滞回耗能能力较高，但延性相对较差；顶底角钢全螺栓连接半刚性节点承载能力、滞回耗能能力相对较低，延性较好；外套管式端板连接半刚性节点的极限承载力、滞回耗能能力和延性性能都有良好的表现；在此基础上，对外套管式端板连接半刚性节点进行了荷载-位移影响参数分析。结果表明:轴压比在弹性阶段对节点的影响不大，在进入屈服和塑性强化阶段，随着轴压比的增高，节点的极限承载力和延性下降；在强柱弱梁的前提下，梁柱线刚度比的增加有利于节点弹性刚度和水平极限承载力的提高，屈服后梁柱线刚度比对节点刚度退化影响不大；钢材屈服强度影响主要体现在节点的极限水平承载力上；再生骨料取代率对节点的延性性能稍有影响；外套管和端板的厚度变化在一定范围时对节点的弹性刚度和极限承载力有一些影响，但增幅随着厚度的增加越来越小。

Seismic Behavior of Steel Recycled Concrete Column and Steel Beam Joint of Square Steel Tube

Considering the nonlinear and plastic damage constitutive of recycled concrete and geometric, three steel recycled concrete column and steel beam joint finite element models including outer-shell stiffening ring all-welded rigid connection, the outer tube end plate connection semi-rigid connection, and bolt connection of top and seat angle, were established, and the seismic performance of models were analyzed. The results show that under the condition of low cycle load, the columns with supporting skeleton and without through member are beneficial to improve the integrity of core recycled concrete in joint area, and the force is simple. The outer-shell restraint joint domain stress and strain of the core recycled concrete are small, which are beneficial to the improvement of the durability of recycled concrete. Under the same compression ratio, stiffness ratio of beam to column, the bearing capacity and hysteretic energy dissipation capacity of outer-shell stiffening ring all-welded rigid joints are higher, but the ductility is relatively poor. The semi-rigid bearing capacity and hysteretic energy of bolt connection of top and seat angle are relatively low, and the ductility is good. The ultimate bearing capacity, hysteretic energy dissipation capacity and ductility of the outer tube type of semi-rigid end plate connections all have good performance. On this basis, the impact parameter analyses on semi-rigid joints connected by casing pipe end plate were carried. The results show that the axial compression ratio has little effect on the node in the elastic phase, in the yield and plastic hardening stages, with the axial compression ratio increases, the ultimate bearing capacity of the joint and the ductility decrease. In the premise of strong column weak beam, the increasing of linear stiffness ratio of beam to column are benefit with the improving of joint elastic stiffness and ultimate bearing capacity, beam column stiffness ratio and after yielding have little effect on joint stiffness degradation. The impact of yielding strength is mainly reflected in the ultimate horizontal bearing capacity of joints, and the replacement rate of recycled aggregate has a little effect on the ductility performance of joints. The thicknesses of outer tube and end plate have some effects on elastic stiffness and ultimate bearing capacity of joints in a certain range, but the growth rate becomes smaller with increasing thickness.