钢管混凝土柱脚节点抗冲切性能试验

Experimental Study on the Punching Properties of the Concrete-Filled Steel Tubular Column Base Joint

目的研究钢管混凝土柱与钢筋混凝土基础梁柱脚节点的抗冲切性能和在竖向荷载作用下的破坏模式,解决实际工程中的柱脚节点破坏形态和抗冲切承载力问题.方法通过两个埋入基础梁式钢管混凝土柱脚节点的缩尺模型试件在竖向荷载作用下的试验,观察柱脚节点的破坏形态、破坏机理、冲切破坏面位置及影响冲切承载力的因素.结果钢管混凝土柱脚节点在竖向荷载作用下若不采取附加构造措施将发生冲切破坏,冲切破坏面从钢管底部高度处开始,与竖直方向夹角略大于45°.结论冲切破坏的承载力小于节点受弯、受剪破坏的承载力.建议相关设计规范应规定对该种柱脚节点进行抗冲切计算,或对钢管外焊接栓钉、抗剪环等构造等措施,保证节点的抗冲切性能.

Punching strength of the concrete-filled steel tubular column, its foot base joint and the failure model under the vertical load are studied in this paper to solve the problems of failure model and capacity resisting punching shear of the joints in practical engineering. Through the vertical load tests conducted by two reduced scale models of concrete-filled steel tubular column base joint that were buried in foundation, the research observes the failure model, failure mechanism, the location of failure surface of the joints and the factors affecting the beating punching ability. If additional structured measures are not added, the punching failure of concrete-filled steel tubular column base joint will happen under the vertical load. The location of the failure surface begins from the bottom of the steel tube and the angle is a little bigger than 45° with the vertical direction. The punching shear strength is lower than the capacity of the bending and the shearing strength. It is suggested that the computing of punching shear strength of the joint or other constructed measures on welded cotter outside the steel tube and the rings resisting shear should be specified in the related codes. They are able to guarantee the capacity of resisting punching shear of the joint.