The US Federal Highway Administration has conducted considerable research to quantify the heat straightening process. The technical data from this research is presented in the FHWA'S Technical Guide and Manual of Practice for Heat Straightening Repairs of Damaged Steel. The basic concept of heat straightening is relatively simple. Heat straightening repair of a damaged steel member involves applying a limited amount of heat in specific patterns to the plastically deformed regions in repetitive heating and cooling cycles to produce a gradual straightening of the material. Properly conducted, heat straightening is a safe and economical procedure for repairing damaged steel. In May 2000 the Highways Agency undertook a trial of the technique to in the repair of New Road Overbridge, which had been damaged by the tipping mechanism of an articulated container vehicle. The trial was completed in 10 days, including painting and cut the cost of repairs by about half. The Highways Agency has now completed the repair of more damaged bridges and is developing an advice note on the application of the technique for composite steel bridge beams in the UK. The principles of heat straightening and the design, supervision and application of the technique to repair to composite steel bridge beams are described in this paper.
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