Investigation and treatment of bearing diseases for typical expressway and high-speed railway bridges in Eastern China: a field practice campaign

As an important part of a bridge, bearings are vulnerable to damage when exposed to various loading and environmental changes during their lifetime, resulting in the necessitating repair or replacement operations. The investigation and maintenance of bearings' diseases are helpful to prolong their durability. Compared with laboratory research, the field investigation of bearing diseases is more representative due to the realistic working environment. In this paper, the defects of 10,486 bearings in 19 expressway bridges and 8,862 bearings in 5 high-speed railway (HSR) bridges in Eastern China are inspected through manual on-site visual observation and parameter measurement, followed by a large amount of bearing diseases data obtained to perform a statistical analysis for evaluating many aspects, including the classification and the potential causes of the bearing diseases, the service status. Finally, a three-level maintenance strategy for bearings is developed and applied to the replacement of 1,166 bearings in eight expressway bridges and 15 bearings in seven girders of HSR bridges. The results show that most diseases of elastomeric bearings are caused by design defects but for pot or spherical by the problems remaining from bearings installation, and the proposed bridge jacking scheme and bearing replacement technologies are efficient, labour- and material-saving.