Failures of high strength stainless steel bridge roller bearings: A review

With the innovation of elastomeric bearings in the mid-1950s steel bearings lost their interest and significance both in research and development and subsequently even in application. Steel bearings were gradually abandoned in bridges, followed by the technical literature and design standards. However, a great number of steel bearings remain today in service world-wide and will pose their particular challenges in the future. To the author’s knowledge, just in Sweden, high strength stainless steel bearings still exist in no less than some 650 bridges. In recent years, a large number of such bearings have failed with an alarmingly high frequency in Sweden during a period of six to twenty years after installation making them a serious maintenance cost issue. After a brief summary of the history of high strength stainless steel bearings, the paper reviews service experience of such bearings in Sweden and elsewhere. Accompanying finite element analyses were performed in order to gain insight into the likely failure mechanism. Finally, this comprehensive review leads to a conclusion that identifies the causes of the failures occurred and makes some recommendations. Although previous investigations of the stainless steel bearings have not been able to clearly identify the cause(s) of the failures occurred, it is found that the failures primarily occurred due to initiation of cracks through stress corrosion cracking followed by fatigue crack growth requiring a certain stress range and a sufficiently large number of cycles until final failure ensued through sudden and instable fracture after fatigue growth to a critical crack size.