Heat-Straightening Repair of Damaged Steel Bridge Girders

This article describes the best uses and the limits of heat-straightening repair when applied to steel bridge girders that have been damaged, typically when a vehicle strikes a member such as a hanger in a through truss. This article gives additional information about the subsequent fatigue and fracture performance of heat-straightened bridge members, in order to better show when heat-straightening can be an economical and safe alternative repair strategy. This is based on the results of NCHRP project 10-63, which was initiated: to determine the effects of repeated damage and heat straightening, to identify and quantify material and process parameters limiting its effectiveness, and to establish guidelines, including limits on the damage and number of damage/repair cycles. Damage was simulated with a very large weight-drop machine designed for this project. The various scenarios tested are described, along with results. They include: useful inspection techniques, “pre-repair” repairs, repair of transverse stiffener details, influence of residual damage, and influence on fatigue life.