Effects of Realistic Heat Straightening Repair on the Properties and Serviceability of Damaged Steel Beam Bridges

Abstract

The permanent deformations in steel beam bridges caused by collision with high profile vehicles can be repaired by heat straightening, which is a structurally efficient and cost-effective repair process developed by many engineers over the years. Guidelines for conducting heat straightening repair have been developed by the Federal Highway Administration (FHWA) and many state departments of transportation (DOTs). The guidelines establish limits for: (a) the maximum damage that can be repaired, (b) the maximum restraining force, and (c) the maximum heating temperature to prevent the side effects of heat straightening repair process. However the heat straightening guidelines are violated in the field due to time and economic issues. These violations include, but are not limited to: (a) underheating below 1200°F, (b) overheating above 1200°F, (c) overstraining above restraining force limit (0.5 Mp) and (d) multiple heat straightening of the same beam more than two times. Currently, there is a lack of knowledge of the effects of these imperfections in the heat straightening repair process on the condition and serviceability of the damaged-repaired beams. This knowledge is needed to develop more realistic guidelines for evaluating and replacing bridge members subjected to damage followed by imperfect heat straightening repair. The overall goal of this research is to develop recommendations and guidelines for evaluating steel beam bridges in Indiana subjected to damage followed by heat straightening repair with imperfections (overstraining, overheating, or multiple heat straightening).