Thermal Load Design Philosophies for Horizontally Curved Girder Bridges with Integral Abutments

Abstract

A small degree of uncertainty has been observed in determining the significance of thermal loads when designing the superstructure of a horizontally curved steel bridge. This investigation focuses research on a three-span curved bridge with fixed piers and integral abutments. Combining horizontal curvature with increased levels of fixity (e.g., integral abutments and fixed piers) presents a growing concern with regard to the influence of changing temperatures. The purpose of this work was to analytically investigate bridge superstructure behavior under design thermal loading conditions. In doing so, a bridge previously subjected to an empirical field study was modeled using a commercial finite-element analysis software package. The results indicated that thermal stresses in the lower flange of the girder were greatest at the fixed pier locations. These stresses were mostly the result of lateral flange bending caused by the pier restraining lateral movement of the girder. While these stresses were small for this particular bridge, adding only up to 20,684 kPa (3.0 ksi), bridges incorporating integral abutments and fixed piers with increased curvature and skew may require special attention in future practice.