节点区柱钢管不全贯通式钢管混凝土柱-梁节点区的受压试验研究

Experimental Investigation into a New Type of Concrete-Filled Steel Tubular Column-Beam Joint with the Discontinuous Column Tube in Joint Zone Under Compression

对节点区柱钢管不全贯通式钢管混凝土柱-梁节点进行了7个试件的轴压试验及2个试件的偏压试验,研究了梁通过处钢管开孔及各层间钢管柱分离两种型式的柱钢管不全贯通式节点的力学性能,包括轴压及偏压的受压破坏形态、开裂荷载、极限承载力、结构变形能力,以及环梁钢筋、钢管及纵筋等部件的受力特性.结果表明:不全贯通式节点在环梁和环向钢筋约束下具有较高的承载力和较好的延性;钢管在梁位开孔(型式一)与钢管在节点区完全分离(型式二)的两种试件具有相同的节点区破坏形态及相近的力学性能;随着偏心距的增大,偏压试件的极限荷载及极限应变有减小的趋势;偏压构件的环筋应变沿受压侧向受拉侧衰减,形成不均匀的约束力;柱纵筋轴向压应变有沿节点区向两端衰减的趋势.

In this paper, the experiments of the concrete-filled steel tubular （CFST） column-beam joints with discontinuous column tube in the joint zone were carried out with 7 axial and 2 eccentric compressive specimens. The mechanical performances of two types of joints, including the failure mode, the crack load, the ultimate bearing capacity, the structural deformation and the strains of ring bars, steel tubes and longitudinal bars, were then investigated. In the joint of Type 1, the columns were separated on each floor, while in Type 2, the openings were cut on the column tube at the corresponding beam place. The results show that （ 1 ） under the constraint of concrete ringbeams and ring bars, the joints are of good ductility and high bearing capacity ; （2） the two types of joints have the same failure mode and similar mechanical performances; （3） both the ultimate bearing capacity and the strain of eccentric compressive specimens decrease with the increase of the eccentricity ; （4） the strains of the ring bars of eccentric compressive specimens tend to decrease from the tension side to the compression side, thus resulting inasymmetric constraints ; and （5） the strains of longitudinal column bars tend to decrease from the joint zone to the ends of the column.