反复荷载作用后新型钢管混凝土柱-混凝土梁节点的轴压试验研究

Axial compression experimental research on the new type concrete-filled steel tubular column-concrete beam joint after cyclic loadings

为了解新型钢管混凝土柱-混凝土梁节点在地震后的力学性能,对经历了低周反复荷载作用的节点试件进行轴压试验,探讨该新型节点在轴压荷载作用下的破坏形态、极限承载力及其应变特点。试验结果表明,试件在轴压过程出现两种不同的破坏形式,其中节点截面尺寸较小的试件表现为节点的破坏,而节点截面尺寸较大的试件则表现为柱钢管屈曲失效,并明确两种不同的破坏形式中,节点钢筋网在震后带损伤的情况下仍能够充分发挥其强度,节点在钢筋网约束与扩大横截面的局压受力机理作用下其承载力得到提高。通过合理设计的新型节点的承载力可高于钢管混凝土柱的承载力,可实现"强节点,弱构件"的抗震理念。

In order to investigate the mechanical behavior of the new type concrete-filled steel tubular column-beam joint after earthquake, the axial compression experiment was carried out on specimens after cyclic loadings. The failure modes, the ultimate bearing capacity and the features of the strains were discussed. The results indicate that two failure modes occur in the test. For specimen joints with small cross section, failure region is concentrated within the joint. On the contrary, for those with larger cross section, failure is the buckling of concrete-filled steel tubular column. After the earthquake, the mat reinforcement of joints can still give full play to its strength and the capacity of the joints increases by the confinement of mat reinforcement and local compressive effect of the enlarged cross section. Through the reasonable design, the bearing capacity of the joint zone is higher than concrete-filled steel tubular column, which meets the seismic design requirement of weak member and Strong joint.