单边螺栓连接T形件-钢管节点高温下及高温后受拉性能

Tensile behavior of one-side bolted T-stub to tube connection at fire and post-fire circumstances

通过试验,研究螺纹锚固单边螺栓连接节点在高温下及高温后的受拉性能,并与标准高强螺栓连接节点进行比较.在高温试验中,采用恒温加载和恒载升温2种方式,研究不同温度及荷载比对节点破坏模式及承载力的影响;在高温后试验中,研究火灾阶段的温度及荷载对节点破坏模式和承载力的影响.试验结果表明,单边螺栓连接T形件-钢管节点存在4种典型破坏模式,且高温下和高温后节点的破坏模式均不会发生改变.随着温度升高,节点承载性能下降明显,但试验节点在屈服前均未出现钢管柱壁上的螺纹破坏.在高温后试验中,节点的残余承载力与常温下基本相同,表明节点在火灾后仍具有良好的承载力.节点发生端板屈服伴随螺栓破坏时的单边螺栓性能与标准螺栓相近.根据试验结果,提出单边螺栓节点高温下的承载力计算方法,所提公式的计算结果与试验结果吻合较好.

The tensile behavior of the thread-fixed one-side bolted T-stub to tube connection under fire and post-fire circumstances was studied.Fire tests were conducted using both transient-state and steady-state methods,and a comparison was made with standard high-strength bolted connections.The post-fire test analyzed the influence of temperature and applied load on the residual behavior of the connection.The results revealed four typical failure modes of the connection,all the four modes remained unchanged in both fire and post-fire scenarios.The connection exhibited a rapid decrease in tensile performance at high temperatures.No thread failure on the steel tube column wall occurred before yielding in the connection.In the post-fire test,the residual load-bearing capacity of the connections was basically the same as at room temperature,indicating that the connections still possess good load-bearing capacity after a fire.The performance of the one-side bolts in connections with end-plate yielding accompanied by bolt failure is similar to that of standard bolts.Based on the test results,a method for calculating the load-bearing capacity of one-side bolted connections at high temperatures was proposed,and the calculated results matched well with the test results.