Abstract

Fitness-for-purpose (FFP) assessment is used for estimation the durability of welded plate girders in Poland’s four oldest welded railway bridges. For the girders, the 20.2 m span length was designed. The bridges were constructed over the years 1937-1939 and now being readied for refurbishment. The first radiographic tests on the butt welds in 18 bridge plate girders were conducted in 1958 during which 101 internal cracks in 49 butt weld splices were found, and which were subsequently riveted. The usefulness of such a strengthening is assessed upon structural calculations for design and service loadings, fatigue tests on specimens with internal cracks in the welds, literature service strength of welds with cracks and design fatigue strength of welds with cracks using FFP assessment. The results provide a unique experimental database on the behavior of welds with inadmissible imperfections. They also allow to assess the likely length of their further service life.