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建筑火灾发生频繁且对钢结构危害严重,但总体而言绝大多数火灾并未造成钢结构的根本性破坏,尽快鉴定其火灾后安全性并进行加固修复,对于减小灾后间接经济损失意义重大。高强度螺栓摩擦型连接是钢结构最常用的连接方式之一,其火灾后受力性能对整个结构灾后承载的安全至关重要。但目前国内外对高强度螺栓连接高温过火冷却后的受力性能研究极少。本文对高强度螺栓摩擦型连接进行了火灾后抗剪试验研究,得到了连接的抗滑移承载力、极限承载力以及荷载—变形曲线,研究了过火温度、冷却方式对连接受力性能的影响。为模拟火灾中的可能情况,试验考虑了自然冷却、泼水冷却两种冷却方式。试验表明,当高强度螺栓连接的过火温度不超过400°C时,连接的抗滑移承载力、极限承载力下降小,可判定连接仍能承受外部设计荷载,不需要对连接进行加固或替换螺栓;当过火温度超过400°C时,连接的抗滑移承载力、极限承载力开始显著下降,需连接更进一步的检测并进行仔细的结构分析,以确定连接能否继续承受外部设计荷载,以及是否需要采取必要的加固与修复措施。
The occurrence of building fire is frequent and the steel structure is seriously damaged. However, most of the fires did not cause fundamental damage to the steel structure as a whole, as soon as possible to identify their post-fire safety and reinforcement and repair, which is significant for reducing the indirect economic losses after the disaster . High-strength bolt friction connection is one of the most commonly used steel structure connection, and its post-fire force performance is crucial to the safety of the entire structural post-disaster load. However, at home and abroad, the research on mechanical properties of high-strength bolted high-temperature overcooling is extremely rare. In this paper, the post-fire shear test of high-strength bolt frictional connection was carried out. The anti-slip bearing capacity, ultimate bearing capacity and load-deformation curve were obtained. The influence of over-temperature and cooling mode on the mechanical properties of the connection . To simulate the possible fire situation, the test considered the natural cooling, splashing water cooling two cooling methods. The test shows that when the over-temperature of the high-strength bolt connection does not exceed 400 ° C, the anti-slip bearing capacity and the ultimate bearing capacity of the connection decrease slightly, and the connection can still be judged to be able to withstand the external design load without reinforcing or replacing the connection Bolts; when the over-temperature exceeds 400 ° C, the connection of the anti-slip bearing capacity, the ultimate bearing capacity began to decline significantly, the need to connect further testing and careful structural analysis to determine whether the connection can continue to withstand external design load, As well as the need to take the necessary reinforcement and repair measures.