FATIGUE IMPROVEMENT METHOD FOR EXISTING BRIDGE BY LOW TEMPERATURE TRANSFORMATION WELDING MATERIALS

Abstract

The Fatigue Improvement method using low temperature transformation (LTT) welding material for bridges in use was examined by welding tests, girder-model fatigue tests, and residual stress measurements. As the results of these examination, it is found that careful examination in installation is needed, if the structures have webs thinner than 12mm, and steels softer than SM570, and LTT weld is installed both sides of webs at the same point. Bt using adequate type of LTT material and keeping the heat imput smaller than 13kJ/cm, JSSCD class fatigue performance is obtained.