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

Abstract:

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.