Applicability and structural response for bearing system replacement in suspension bridge rehabilitation

摘要

Suitable maintenance, rehabilitation, and repair methods for long-span bridges should be decided based on their purposes as evaluated by carrying out close inspection and observation. This study deals with a rehabilitation method, its applicability to a long-span bridge with a fatigue crack in the stinger-bearing connection plate. Replacing line type contact bearing systems with pot bearings was proposed as the rehabilitation method to stop fatigue cracking, reduce local stress of the fatigue-cracked connection plates, and improve the structural behaviors of the main suspension bridge members. Thus, a stringer-bearing connection specimen was fabricated; then, gouging and bracket installation were simulated for replacing a deteriorated bearing system with a new bearing system. From the results of the gouging and bracket-installation test, the applicability of the rehabilitation method for change works was verified. In addition, the structural responses of the loading tests were compared with those of a finite element analysis in terms of changes in bearing conditions. The deformations of the stringer and the end-beam improved, and local stress and displacement in the fatigue-cracked connection plate were reduced owing to the bearing system replacement. Therefore, replacement of the bearing system can improve the stress level and stop further fatigue cracking in fatigue-cracked connection plates of suspension bridges. In addition, these results can provide basic information about the rehabilitation method involving replacing the bearing systems of bridges with line type contact bearings.