THE BEHAVIOR OF HIGH-STRENGTH GRADE 8.8 BOLTS IN FIRE
THE BEHAVIOR OF HIGH-STRENGTH GRADE 8.8 BOLTS IN FIRE
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DOI：
10.1016/0143-974x(94)00013-8
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发表时间：
1995-01-01
影响因子：
4.1
通讯作者：
KIRBY, BR
中科院分区：
文献类型：
--
作者：
KIRBY, BR
在温度高达800摄氏度的情况下，对高强度8.8级螺栓进行拉伸和双剪切的全部件试验表明，目前英国在防火极限状态下的设计指南BS5950：Part 8，在大部分情况下是保守的。提出了新的指南。拉伸试验与8.8级螺母相结合，突出了由于螺纹剥离可能导致的过早失效。这一机制被发现由两个组件之间的匹配度控制。建议了使螺栓的全部能力得到充分利用的实用措施。采用不同制造工艺生产的螺栓的机械加工试件进行了常规的热拉伸试验。在正常设计应力与塑性变形开始时重合的温度区域内，这两种应力显示出相似的0.2%的验证应力。这些数据还与欧洲法规草案中给出的结构钢的数据进行了比较。对于火灾后的评估，温度对高强度螺栓的残余硬度的影响突出了它们的机械性能对过热的敏感性。利用冶金变化开发了一种确定螺栓在火灾中可能达到的最高温度的技术。这些信息可以帮助调查被火灾损坏的建筑物。
Full component tests on high-strength Grade 8.8 bolts in tension and double shear at temperatures up to 800-degrees-C have shown the present UK guidelines for designing at the Fire Limit State, BS5950: Part 8, are, for the most part, conservative. New guidelines are proposed.The tests in tension, in combination with Grade 8.8 nuts, have highlighted the possible premature failure due to thread stripping. This mechanism was found to be controlled by the degree of fit between the two components. Practical measures are suggested to enable the full capacity of the bolts to the utilised.Conventional hot tensile tests were carried out using mechined specimens from bolts produced by different manufacturing processes. These were found to exhibit similar values of 0.2% proof stress over the temperature region where the normal design stresses coincide with the onset of plastic deformation. The data are also compared with those given for structural steel in the draft Eurocodes.For post-fire evaluation, the influence of the temperatures attained on the residual hardness of high-strength bolts has highlighted the sensitivity of their mechanical properties to overheating. Use has been made of the metallurgical changes to develop a technique for identifying the maximum temperature bolts may have achieved in a fire. This information can assist in the investigation of fire-damaged buildings.