Fabrication of unsymmetrical curved plate girders by cold bending

Abstract

A proprietary cold bending method was recently developed for the fabrication of the steel girders in the Miami Metromover. In an earlier paper, the authors developed a simplified analysis for this system that could be used for curving symmetrical girders. This paper extends this analysis to unsymmetrical girders typically used in bridge construction where the top flange is smaller than the bottom flange. Guidelines are proposed that set limits on the maximum load and permanent residual strains that develop during the curving operation to ensure they are within acceptable norms. These are integrated in a standardized procedure based on actual practice. A comprehensive numerical example is included to illustrate this procedure. This uses design aids specially developed to simplify calculations in the steel shop.