LESSONS FROM WELD CRACKS IN ORTHOTROPIC DECKS ON THREE EUROPEAN BRIDGES

Weld cracks in orthotropic decks with closed ribs on the Haseltal and Sinntal bridges in West Germany and on the Severn Crossing in the United Kingdom occurred at the intersections of the discontinuous ribs with the floor beams and at the rib-to-deck welds, and were caused by inappropriate details and welds not suitable for transmitting stresses between the deck components at these junctions. Good practice requires continuity of the ribs through the floor beams, the use of welds with good penetration into the rib webs at their junction with the deck plate, and avoidance of welded attachments to the ribs or to the deck plate. No weld failures or cracks are known in orthotropic bridge decks with correct details and general performance record of such decks is satisfactory. Careful design, detailing and fabrication of orthotropic decks is essential, especially in cases with long rib spans. Insufficient attention to details can result in costly failures; there is no reason, however, to question the reliability of orthotropic decks where the rules of good design and fabrication practice have been observed.