Researh On Temperature Field Of Concrete Filled Steel Tubular Arch Rib

Temperature effect is important in calculation theory of concrete filled steel tubular (CFST) arch bridge. The main problems about it are the temperature field in space and temperature variation with time. This paper focused on the temperature distribution of concrete filled steel tubular arch section during its construction and its service phase under solar radiation.This paper analyzed the temperature field of CFST member by using finite element method. At first the finite element theory for temperature analysis is introduced, and then mainly discussed the calculation models of cement hydration heat and the boundary condition under sun radiation.The analysis on the models of cement hydration indicated that the compound exponent model is the appropriate one compared with other models of cement hydration heat. Parametric study indicates that steel thickness has small influence on the temperature field of CFST arch rib during construction, while diameter of tube has great influence. The thermal conductive coefficient of concrete has some influence on the temperature field; but for the concrete with same aggregate, the coefficient varies in small range, so its influence is limited.This paper carried out two temperature field tests of CFST members, one member placed vertically and another member placed horizontally. The analysis on the test result shows that the temperature distribution in CFST members caused by solar radiation is nonlinear,and the nonlinear character is most evident when center point of concrete gets its lowest temperature. The temperature of the center point is affected by various directions, especially the strong potential. In the side exposed to the sun in the afternoon, apart from the center point, temperature varies laggardly when the point of concrete in the same series is more close to the center. But in the side not exposed to the sun in the afternoon, temperature varies laggardly when the point of concrete in the same series is more close to the center.General finite element program was used to calculate the temperature field. The calculating result agreeing well with the test result shows that the simulation of solar radiation in this paper is feasible.But the method includes complicated handwork when calculating the boundary condition of solar radiation, and how to realize the auto calculating needs further study in future.