Material and cost-efficient optimized steel designs for long fatigue life - LONGLIFE

Important results from the project

The project has achieved most of the set goals. The concept of corrugated webs in bridge and crane runway girders has been tested and verified through FEA and experiments. Models for fatigue strength and instability are now ready and the concept is ready for implementation. The optimization tool, the best solution can be selected based on environmental and cost-effectiveness. The project has also led to increased knowledge about the effectiveness of HFMI in stainless- and weathering steels.

Expected long term effects

LONGLIFE is the latest in a series of projects with the ultimate goal of enabling sustainable infrastructure construction. Over the years since the first feasibility study was completed, we have seen an increasing number of stainless steel bridges, mainly as pedestrian bridges. The results from LONGLIFE should lead to more fatigue-loaded bridges being constructed in stainless steel. LONGLIFE has also helped to put implementation of weathering steels in bridge applications on the agenda.

Approach and implementation

The project contains a large amount of experiments. It involves the manufacture of beams with corrugated webs in different geometries and different test specimens as well as fatigue testing. Currently, there is no supplier in Sweden that can cost-effectively achieve the desired corrugations for small series. The project was extended due to various difficulties with manufacturing and testing. It has gone well thanks to the good efforts and understanding from all participants.