Temperature Distributions and Variations in Concrete Box-Girder Bridges: Experimental and Finite Element Parametric Studies

In this research, a full-scale, experimental box-girder bridge segment and three dimensional finite element thermal studies were conducted to investigate the temperature distributions and variations in concrete bridges under environmental thermal loads, with particular reference to the influence of the thermal properties of concrete. Applicable ranges of the studied properties were gathered from an extensive literature survey. One-way analysis of variance was used to evaluate the effect of the concrete properties of interest, demonstrating that density and surface emissivity have negligible effects. Parametric studies showed that the combined effects of thermal conductivity, specific heat, and solar absorptivity may increase the maximum bridge temperature by approximately 25%. Analysis of extreme thermal conditions indicated that these combined effects increased the mean bridge temperature by approximately 15 to 20%. Moreover, it may cause vertical temperature gradients exceeding the AASHTO's and the Bridge Manual's vertical gradients by up to 10 degrees C.