Temperature Problem Research On Rigid-Framed Arch Bridge Structure

Rigid-framed arch bridge is a statically indeterminate structure with thrusting force and over the cross section of the bridge structure induce obvious stresses resulted from temperature variations. However, because of the complexity of this bridge structures, it is so difficult to calculate temperature stress, and that researchers and designers have to simplify the calculating methods, and get inaccurate conclusions. Therefore, temperature problem is one of vitally important research topics in structure designing of rigid-framed arch bridge. Based on the previous research results, the author takes nonlinear temperature load equivalent to linear temperature load and calculates temperature stress by FEM. It analyses the whole and the part temperature effect on rigid-framed arch bridge and compares different thermal stress of different bridge structure by the simplified methods. The research offer advices for this new style bridge. Also the experimentation proves the validity of the aforementioned methods. The contents include:Based on the previous research and the data of experimentations, the author researches and develops a kind of satisfactory semi-empirical formula of nonlinear temperature distribution, and calculates the temperature stress of rigid-framed arch bridge by the FEM. The temperature effects of bridge structure by annual and sunlight temperature difference are discussed, it indicates that the temperature effect of annual temperature difference is small but the temperature effect of sunlight temperature difference is great and the temperature stress along beam depth resulted from sunlight temperature difference is nonlinear. With the comparison between the temperature effects of different position of bridge, the results show that where the section of bridge is small, the temperature stress of it is large. The box beam's temperature stress of longitudinal direction and transverse direction with different conformation are analyzed, it finds that there is largish temperature tensile stress in the bottom of top deck and the haunch of box beam increase temperature tensile stress in the bottom of top deck. The paper makes a study of different thermal effects resulted from several kinds of closed rigid framebridges, then summarizes the virtue and shortcoming of these bridges under the temperature loads, and discusses the corresponding measures of them.The paper uses exponent function formula to fit the temperature distribution of box beam on the base of a lot of experimentation data of temperature. It is proved by this way that the calculating results close to the experimentation's data and the calculations are simple. By comparing observation of Youxizhou Bridge's temperature distribution and stresses in summer, autumn and winter with the calculating results by the aforementioned methods, the research validates the correctness of the methods of calculating temperature stress.