Statistical Analysis of Thermal Actions for Concrete Bridge Design

Thermal effects have often been associated with concrete bridge damage. The non-linear temperature distributions that arise in bridges are difficult to estimate and are often considered in a simplified way by designers, which may lead to structural behaviour problems. In this paper, a methodology is presented, based on a statistical analysis of temperature distributions, that may be used to define the differential and uniform variations of temperature. Examples are presented for the climatic conditions in Portugal. Temperature distributions were obtained by considering a numerical technique for resolution of the Fourier heat-transfer equation, taking into account the geometry of the bridge cross section, the thermal properties of concrete and asphalt, and climatic conditions. The validity of this technique was confirmed using experimental data from instrumented bridges. By considering the available meteorological data, a statistical analysis was performed to obtain characteristic and combination values.