THERMAL PROFILES IN BRIDGES USING FEM

Abstract

The study of the behaviour of concrete structure under environmental thermal effects in order to predict the thermal actions to be considered in design or the thermal response at the sectional level and the stress distributions at sectional and structural levels has increased significantly in recent years. Thermal effects have been frequently associated with concrete-bridge damage. The nonlinear temperature distributions that ariese in bridges are not easily estimated and are often considered in a simplified way, which way lead to structural behaviour problems. In the present work, a discussion of current design code provisions is referred to and an approach for estimation of the temperature distributions considering a numerical technique for the resolution of the Fourier heat transfer equation and its associated boundary conditions is taken within a computer program in FORTRAN. This technique is based on the Finite - Element method and takes into account the geometry of the bridge crass-section, the thermal properties of concrete and asphalt, the location of the bridge and climatic conditions. Based upon extensive parametric studies carried out in the present work, an attempt has been made to propose design temperature gradient values.