The century-old Harvard bridge spans the Charles River between Boston and Cambridge. About half of the 23 spans are suspended by wrought iron eyebars. Recent failures of some of these eyebars were examined. The primary cause of failure was the seizure of the joints at the eyebar pin locations as a result of the intrusion of water and salt, and the consequent heavy corrosion of the joint. The seizure of these joints led to high edgewise bending stress in the bars as the bridge underwent thermal movement. The cracking was enhanced by the presence of the corrosive medium so that the cracks were initiated and caused to grow by some combination of corrosion fatigue and stress-corrosion cracking, the former probably being predominant.

While a chain sling was being used to lift a casting one of the links ruptured. The sling, reputed to be of the electrically-welded steel type, was at least eight years old and had been overhauled several times during its working life. Examination showed the links were scarf-welded. Furthermore, the welds were at the ends and not at the sides as is usual in the case of electrically-welded chains. A transverse section from one side of a link was examined microscopically. This showed the material to be wrought-iron of satisfactory quality. It was concluded this chain sling had been made from wrought-iron, forge welded in the usual manner, and that it was not electrically-welded steel as had been supposed. Failure was attributed to embrittlement in service of the surface material of the links. If it had been realized that the sling was made from wrought-iron then it would doubtless have been subjected to periodical annealing in accordance with Statutory requirements, which would have restored the ductility of the surface material.