Post weld treatment - Implementation on bridges with special focus on HFMI

Report, 2014

Post weld treatment is a measure of fatigue enhancement of steel and aluminum structures and is today a common procedure in many industries due to the substantial improvements that is gained by it. In the bridge industry, steel and composite bridges have lost competitiveness in recent years due to high requirements on the fatigue design, resulting in more use of material. Although, experiences regarding post weld treatment have not come as far in this industry, studies indicate that large savings with more than 20% material reduction can be achieved for a bridge. This combined with the fact that higher material grades increase fatigue performance after treatment, yields considerable economic advantages and positive effects on the bridges life cycle costs, not to forget the environmental benefits. Herein, examples of nine new and old bridges that have been subjected to post weld treatment are presented, together with international studies regarding fatigue improvement assessment and procedure and quality control recommendations. Furthermore, studies of modeling this technology by finite elements are presented to show the extent of knowledge that exists within this filed, including residual stress simulations, simulations of the post weld treatment and fatigue simulations by different methods. This is of importance for making parameter studies and gain more experience prior to bridge application.