预应力混凝土梁板高温下非线性分析方法研究

Study on Nonlinear Analysis Method of Prestressed Concrete Beam and Slab at High Temperature

针对预应力梁板在高温下的受力性能,通过理论计算研究了非线性分析方法在混凝土结构受火后力学性能分析中的具体应用。结果表明:对高温结构的内力分析,必须考虑热-力耦合作用,否则计算结果会存在较大误差;瞬态热应变是混凝土高温应变的主要组成部分,随升温过程产生,降温不可恢复,在温度超过前次最高温度时才累积变形;非预应力筋对分析过程影响较小,可采用理想的弹塑性模型进行简化计算;力法中的位移协调方程和割线刚度迭代法是分析高温结构内力变形的有效方法,通过迭代求解可以得到弯矩-曲率关系曲线。

Aiming at the mechanical performance of prestressed beam and slab at high temperature,the specific application of nonlinear analysis method was studied by theoretical analysis.The results show that:thermal mechanical coupling should be considered in the internal force analysis of high-temperature structures,otherwise there will be large errors in the calculation results;transient thermal strain is the main component of concrete high temperature strain,it occurs with the heating process,and it will not recover after cooling.Deformation is accumulated only when the temperature exceeds the previous maximum temperature.Non-prestressed reinforcement has little influence on the analysis process,and the ideal elastic-plastic model can be used for simplified calculation.The displacement compatibility equation and secant stiffness iteration method are effective methods to analyze the internal force and deformation of high temperature structures.The specific process of iterative solution and the bending moment curvature curve can be obtained by iterative solution.