方钢管混凝土柱-H型梁新型节点倒塌性能试验研究

Experimental Study on Collapse Behavior of a Square Concrete-Filled Steel Tubular Column-H-Beam Joint

为提高方钢管混凝土柱-H型钢梁节点连续倒塌工况下的承载力和转动能力,提出了一种H型钢梁下栓接贯通隔板上焊接外环板的新型节点形式,进行了试验研究,分析了腹板连接板处开长圆螺栓孔对节点力学性能的影响.结果表明:与以往节点形式相比,该种新型节点形式具有更高的承载力和更好的转动能力;钢梁的受力符合梁抗弯机制转悬索机制的一般规律;腹板连接板处开设长圆螺栓孔并未削弱连接,反而提高了节点的转动能力和竖向抗力,梁抗弯机制失效后进入悬链线阶段,是钢框架体系中用于抗连续倒塌设计的一种较为理想的节点形式.同时通过对比规范发现,该种新型节点形式承载力符合相关设计要求,此规范可用于该节点的设计和结构屈服预测.

To improve the bearing and rotational capacities of a square concrete-filled steel tubular column with Hbeam joints under progressive collapse conditions,we propose a beam-column connection using a steel beam with an H-shaped lower flange and perforation plate bolting with the upper flange welded to outer ring plates.This joint form was statically tested by electric servo actuator.The influence of an exposed long,round bolt hole on the mechaniccal properties of the joint was also analyzed.Results showed that the proposed connection had higher bearing and rotational capacities compared to previous connection forms;further,the force component of the steel beam conformed to the general beam bending conditions.The long,round bolt holes set at the connecting web plate did not weaken the connection;on the contrary,they improved rotational ability and vertical resistance of the joint.The catenary stage appeared after the beam-bending resistance mechanism failed.Furthermore,we found that the bearing capacity of the connection met the relevant design requirements in accordance with the standard specification.Hence,this specification can be used for the design and structural yield point prediction of the connection.The proposed connection form was found to be ideal for resisting progressive collapse conditions in the steel frame system.