基于等效龄期的钢管拱内混凝土硬化过程热应力

Thermal Stress of Concrete-filled Steel Tube Arch During Hardening Process Based on Equivalent Age Method

为揭示大直径钢管拱内混凝土硬化过程中力学性能增长的温度依赖性因素对组合结构热力作用效应的影响机理,采用有限元程序模拟钢管拱内混凝土的水化热传导过程,并与实测温度场数据进行对比,随后基于等效龄期法考虑其对管内混凝土弹性模量增长的影响,在此基础上结合热弹性力学理论得到了硬化过程中组合结构热应力的变化规律,并与未考虑温度依赖性影响的计算结果进行比较分析.结果表明,水化热温度场加快了管内混凝土硬化过程中弹性模量的增长速度,进而导致混凝土温度应力明显增大,截面径向、环向以及纵向温度应力增幅分别可达1.3倍、1.3倍和1.4倍,但对钢管应力的影响可忽略不计.因此,在分析大直径钢管拱内混凝土硬化过程中的热力作用效应时,必须考虑水化热温度场对管内混凝土弹性模量增长的影响.

In order to reveal the influence mechanism of temperature dependence of development of mechanical properties of concrete in large-diameter steel tube arches on the thermodynamic effect of composite structures during hardening process,a finite element model was established to simulate the hydration heat transfer process of the concrete in the steel tube arch,which was compared with the measured temperature field data.Subsequently,the effect of hydration heat on the development of the modulus of elasticity of the concrete was further considered based on the equivalent age method,by which the variation of thermal stress of composite structure during hardening process were revealed combining with thermal elasticity mechanics theory,and compared with the calculation results without considering the influence of the temperature dependence.The results show that the hydration heat temperature field accelerates the growth rate of the modulus of elasticity of the concrete in the tube during hardening,which leads to a significant increase in the thermal stress of the concrete during hardening process,and the increases in the radial,circumferential and longitudinal directions can reach 1.3 times,1.4 times and 1.3 times,respectively,but the effect on the stress of the steel tube is negligible.Hence,in the analysis of the thermodynamic effect during the hardening of concrete in large-diameter steel tube arches,the effect of hydration heat temperature field on the development of the modulus of elasticity of the concrete in the steel tube must be considered.