火灾下螺纹锚固螺栓T形连接承载力设计方法

A Design Method for Thread-Fixed One-Side Bolted T-stub Connections at High Temperatures

螺纹锚固单边螺栓是指通过带有螺纹的特殊螺栓孔代替螺母,从而实现单侧安装、拧紧功能的一种螺栓。目前关于该种螺栓连接T形节点在常温下不同破坏模式的受拉承载力计算方法已有研究。但在高温条件下节点变形增大,且高强螺栓与普通钢材在高温下的材性折减规律不一致,导致现有的常温计算公式不能直接用于火灾高温情况,目前仍缺少计算该类节点在高温下承载力的计算方法。根据常温下承载力计算公式,结合高温下节点出现大变形的特点,对现有的计算公式进行修正。并根据现有的试验结果对修正公式进行验证,发现提出的设计公式可准确预测不同节点在不同温度下的破坏模式,也可以较为精确地预测其屈服承载力。

The thread-fixed one-side bolt is a bolt whose anchorage is provided by threaded bolt hole instead of nut, and it can be installed and tightened from only one side.The design equations for calculating the failure mode and yielding capacity of the thread-fixed one-side bolted T-stub connections at room temperature have been proposed.However, these equations could not be applied to the high-temperature circumstance for the large deformation of connection and the different reduction law of high strength bolt and common steel.The design equations for the calculation at high temperature circumstance still need to be studied.The equations for high temperature circumstance were modified in this paper by considering the effect of large deformation.The accuracy of the modified equations was verified by comparing to the test result carried out by the authors previously.The comparison showed the modified equations can predict the failure mode and yielding strength of T-stub connections at different temperatures with a good accuracy.