无防火保护钢结构耐火试验的相似理论研究

Study on similarity theory in fire resistance test of exposed steel structure

原型钢结构耐火试验能够较为真实地反映构件在高温下的力学性能,但由于耐火试验炉普遍较小、试验费用较高等原因,一般难以基于整体结构进行结构耐火试验。若要突破结构耐火试验研究的瓶颈、基于部件或整体结构进行试验,其关键是缩尺模型耐火试验的相似理论研究。本文基于传热学与相似理论的研究基础,根据热传导、热对流和热辐射建立温度场相似理论,并在温度场相似的基础上建立热力耦合作用相似理论使模型耐火试验能够较好地反应原型结构的耐火性能,最后通过有限元模拟对上述理论进行验证。结果表明,本文提出的相似理论在无防火保护钢结构耐火试验中具有较高的准确性。

The fire resistance test of prototype steel structure can realistically reflect the mechanical properties of the members under high temperature.However,due to some factors such as the small size of fire test furnaces and the high cost of prototype fire tests,fire resistance tests are generally difficult to perform on the overall structure.So the key not only to break through the bottleneck of structural fire resistance research but also to perform fire resistance test on overall structure and members is the similarity theory of scale model in fire resistance test.Based on the research foundation of heat transfer theory and similarity theory,the heat conduction,thermal convection and heat radiation are used to establish the similarity theory of temperature field.Meanwhile the thermo-mechanical coupling similarity theory is established to reflect the fire resistance of the prototype structure 'better.Finally,by using the finite element simulation to verify above theoris,it is concluded that the similarity theory proposed in this paper shows high accuracy in fire resistance test of exposed steel structure.