Abstract

Bridge structures are exposed to severe environmental conditions over their lifetime as they are continuously gaining and losing heat from solar radiation, irradiation to the sky and convection to or from the surrounding atmosphere. These conditions cause large temperature variations within the structure at any instant of time. In concrete bridges, such temperature variations can result in stresses which can be as large as those caused by dead and live loads. Prediction of such temperature variations is a complex problem since the temperature varies with time, within the bridge cross-section, as well as from section to section along the bridge length. In long straight bridges with constant cross-sections, the assumption that the temperature is constant along the bridge length is valid and a two-dimensional analysis is sufficient to determine the distribution of temperature within the cross-section. However, in curved bridges, a three-dimensional analysis is necessary to predict the temperature distribution within the cross-section and along the axis of the bridge. In the present research, a method of analysis and a computer program based on three-dimensional finite elements are presented to determine the time-dependent temperature variations and the corresponding stresses in box girder bridges of arbitrary plan and cross-section geometry for a given geographic location and meteorological conditions. A comparison is made between the results obtained from the analytical solution and temperature measurements obtained by other researchers on a straight bridge in Quebec to demonstrate the validity of the method of analysis. The program is then applied for a case study to illustrate the three-dimensional temperature distribution in curved concrete box girder bridges. Furthermore, a parametric study is performed to assess the influence of some chosen parameters on the temperature variation along the axis of such bridges