内置高强芯柱的方钢管混凝土柱-钢梁端板-螺栓连接节点的抗震性能

为研究内置FRP约束UHPC高强芯柱的方钢管混凝土柱-钢梁端板-螺栓连接节点的抗震性能，基于“强柱弱梁”目标设计制作5个端板-螺栓连接节点试件，通过拟静力试验研究节点的破坏机理，并分析柱轴压比、FRP管厚度和有无芯柱对节点抗震性能的影响，对比钢梁更换前后节点的性能。试验结果表明：所有试件均在梁端形成塑性铰破坏；该破坏模式下，节点具有较高的承载力、耗能能力和较好的延性；内置芯柱时，试件承载力提高但延性降低；随着FRP管厚度增加，节点初始刚度和耗能能力均得到提升；相比原试件，更换梁试件的耗能能力、延性和初始刚度均有所降低。变形分析结果表明：节点域组合柱以受弯变形为主，两侧钢梁主要承担节点域的剪切变形。依据初始刚度判定该节点属于刚性节点。

Seismic behavior of endplate-bolted joints to concrete filled square steel tubular column with high-strength core

Five joint specimens were manufactured in this study based on the criterion of strong column and weak beam in order to investigate the seismic performance of the endplate-bolted joint of concrete filled square steel tubular with a high-strength core-to-steel beam. A pseudo static test was conducted to investigate the failure mechanism of joints and the effects of axial compression ratio, FRP thickness and the presence of high-strength core on the seismic performance. The behavior of joints before and after replacing steel beams were compared. The test results showed that all specimens eventually failed due to the formation of plastic hinges at the steel beam ends. The joints showed a high bearing capacity, good energy consumption capacity and ductility under this failure mode. The joint encasing the high-strength core exhibited a higher bearing capacity but smaller ductility. The initial stiffness and energy dissipation capacity of the joints were improved as the FRP tube thickness increased. Compared with the original specimen, the energy dissipation capacity, ductility and initial stiffness of the beam replacing specimen were smaller. The deformation analysis results showed that the composite column in the panel zone of the joint mainly undertook the bending deformation, whereas the shear deformation of the joint was mainly carried by the beams. The joints were classified as rigid joint according to the initial stiffness.