考虑瞬态热应变的钢筋混凝土板火灾反应分析

基于非线性温度场理论,编制了钢筋混凝土构件的温度场分析程序;通过对不同温度-应力途径试件力学行为的对比分析,说明了瞬态热应变的重要性,并提出双轴受压状态下瞬态热应变计算模型和瞬态模量的概念;根据大挠度板单元和热弹塑性本构模型,建立了钢筋混凝土双向板的有限元计算模型,对3块钢筋混凝土双向板的火灾行为进行数值模拟,分析了瞬态热应变和膨胀应变对其火灾行为的影响.计算结果表明,计算模型结果与试验结果吻合较好,验证了瞬态热应变模型的有效性,参数分析得出膨胀应变和瞬态热应变对钢筋混凝土双向板的火灾行为有重要影响.

Fire Response Analysis of Reinforced Concrete Slabs Considering Transient Strain

Based on the nonlinear temperature field theory, the temperature program of reinforced concrete member was developed. By analyzing the mechanical behavior of different temperature-stress specimens, the transient strain importance was discussed, and the transient strain model under the biaxial stress state as well as transient modulus was proposed. According to the flat shell theory and thermal elastic-plastic constitutive model, the finite element model of reinforced concrete two-way slab was established to simulate the fire behavior of the three slabs. In addition, the effect of transient strain and thermal strain on the fire behavior of the slab was studied. The results have shown that the predictions agree well with the test results, and the transient strain model is verified. The parametric study indicates that the transient strain and thermal strain have an important influence on the fire behavior of the slab.