Investigation and control of excessive cumulative girder movements of long-span steel suspension bridges

This paper presents an investigation on the premature damage to expansion joints and bearings of long-span suspension bridges, in which failure patterns, locations and mechanism are presented and discussed. According to the field monitoring and time-and frequency-domain analyses, it is observed that the small but rapid girder movements contributed mostly to the large cumulative movements, resulting in accelerated fatigue damage and wear of expansion joints and bearings. Several damage mitigation measures were applied, including the use of more durable friction material, more control springs and movement restraint belts, and their effectiveness is examined through field observation. A supplementary control measure using viscous dampers is finally suggested and the influence of various damper parameters is discussed based on the proposed transient finite element analysis method.