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根据傅里叶热传导理论,提出蒸发阶段水分修正函数,建立改进温度场模型;结合非线性板壳理论和热弹塑性本构关系,建立了火灾下钢筋混凝土双向板的数值模型,发展现有计算程序,通过计算结果与试验结果对比,验证了模型及程序的可靠性。在此基础上,分析了火灾工况、约束作用、骨料类型、板厚和保护层厚度等参数对混凝土双向板变形行为和耐火极限的影响规律。结果表明:火灾工况、骨料类型、板厚和保护层厚度对双向板火灾行为影响较大;双向板变形行为和破坏模式对约束作用非常敏感,力学机理较为复杂。
According to the theory of Fourier heat conduction, a moisture correction function is proposed and an improved temperature field model is established. Based on the theory of nonlinear shell and thermo-elasto-plastic constitutive relationship, a numerical model of two-way reinforced concrete slab under fire is established, and the existing calculation The program verifies the reliability of the model and the program by comparing the calculated results with the experimental results. On this basis, the influence of fire condition, restraint effect, aggregate type, plate thickness and protective layer thickness on the deformation behavior and fire resistance of two-way concrete slab was analyzed. The results show that fire condition, aggregate type, thickness and thickness of protective layer have a great influence on the fire behavior of two-way slab. The deformation behavior and failure mode of two-way slab are very sensitive to the restraining action and the mechanical mechanism is complex.