Study on Large-Scale Repair Plan of the Kanmon Bridge (a Long-Span Expressway Suspension Bridge)

The sliding and rotation functions of the line bearings that support the floor framing stringers have diminished; thus, fatigue cracks have developed in the floor framing around the deteriorated bearings. Also, water that leaks from the expansion joints of the floor framing stringers has caused noticeable deterioration. To prevent further deterioration and damage, replacements of bearings supporting the floor framing stringers, and connection of floor framing stringers were proposed. To secure seismic performance, installations of vibration dampers between the end of the floor framing stringers and the main tower or anchorage were proposed. Additionally, installations of elastic restraining cables were proposed for stability both under normal conditions and during earthquakes. A dynamic analysis of a large-scale earthquake taking into consideration the elasto- plasticity of the steel members was conducted to check the seismic performance.