Replacement of a Tension Flange by Welding

Due to heavy corrosion, a tension flange of a plate girder bridge was replaced. As the bridge crosses over a splendid commercial area and carried heavy traffic, neither temporal support nor traffic interruption was allowed. The replacement was forced to be conducted under service condition, that is, under fluctuating stress condition. A series of experimental studies made for this remedy showed: the stress due to shrinkage of welded joint in the tension flange rolled as artificially induced pre-stress to compensate the deflection by the cutting of the flange; and when welded under fluctuating stress, hot crack was observed in the first layer of deposited metal, which needed to be removed by arc air gouging. 2 ref.--AA