Simplified analysis of heat-curved steel girders

Abstract

Heat curving is commonly used in the fabrication of curved structural steel bridge girders. A two-dimensional superposition analysis known as the Duhamel Analogy was used for numerical modeling in the development of the AASHTO code provisions. This iterative analysis can take into consideration multiple heating-cooling cycles, initial residual stresses, temperature-dependent material properties, and the nonlinear temperature distribution across the girder cross section. A simplified analysis based on the Duhamel Analogy that can be carried out by using hand calculations is described. The curvatures obtained by this method are within 15% of the measured curvatures, which are very comparable to the results obtained by using the Duhamel Analogy or the three-dimensional, nonlinear, finite element solution. The background, basis, and steps required for the proposed analysis are described; and an illustrative numerical example is presented. The proposed analysis may be used to estimate curvatures or to determine the maximum fabrication temperature and the heating width for a single heating—cooling cycle for steels such as high-performance steel not covered by the current AASHTO provisions.