Pure Effect of Temperature on Rectangular and Trapezoidal Box-Girder Bridges – A Finite Element Investigation

Abstract

Since the temperature distributions on concrete bridges are nonlinear, they lead to the self-equilibration of the stress distributions. To have a discussion about strains, deflection, and moment brought on by temperature changes. Three-dimensional finite element, Computers and Structures, Inc (CSI) Bridge finite element software is used to analyze 2 box girder bridge specimens; rectangle and trapezoidal cross section. The box girders were same in depth, span length, cross section details and material properties. These specimens were subjected to different temperatures values. They were tested under AASHTO thermal loading and temperature gradient specification. The finding showed that changing the temperatures at a constant rate during the days of the year, by increasing and decreasing, affects by a fixed amount all of the values of deflection, stresses, and moments, for each of the rectangular and trapezoidal sections by the same amount. Through the values of deflection, stresses and moments for both the trapezoidal section and the rectangular section, it can be seen that the trapezoidal section is affected by the temperature change in a lesser way than the rectangular section. That happened because the rectangular section is affected by the temperature gradient along the section in a greater proportion than the trapezoidal section by 16% in stresses and 56% in terms of deflection.