INVESTIGATION ON MITIGATION OF MAINTENANCE BURDEN OF PILE-SUPPORTED PORT STRUCTURES BASED ON STRUCTURAL ANALYSIS

Abstract

Pile-supported port structures are important infrastructures for physical distribution especially for island countries, for example, Japan. But the motivation for the maintenance of these structures is low and they are not maintained properly because of big burden of maintenance work and high cost. Therefore, the objective of this research is to mitigate maintenance burden of pile-supported port structures in order to increase the motivation for their maintenance and keep the seismic performance properly. Distinguishing between the parts that need to be maintained intensively and the parts where labor can be saved from maintenance to some extent can mitigate the maintenance burden reasonably. This research focuses on both of member scale (RC beam) and structure scale.

In case of member scale analysis, the influence of non-uniform corrosion of steel bars on the performance of RC beams was investigated by COM3 (Non-linear structural FE analysis of RC) because corrosion is non-uniform in real environment. By this investigation, it was found that when considering the seismic performance of RC beams of pile-supported port structure, the influence of non-uniformity of corrosion do not have to be considered. The influence of corrosion on the performance of the RC beam was governed by the distribution of the bending moment when the RC beam is loaded. Therefore the center and edge of the span of RC beams of pile-supported port structure should be maintained with high priority.

In case of structure scale analysis, the relationship between the position of the members (RC beams of superstructure) whose steel bars were corroded and the seismic performance of the pile-supported port structure was investigated by COM3 and T-DAP (Three dimensional dynamic analysis software). By this investigation, it was found that the corrosion of outside beams in the parallel direction to the shoreline and landside beams in the vertical direction to the shoreline gives more severe damage to pile-supported port structure than inside beams during earthquake. Therefore outside and landside beams need to be maintained intensively and the maintenance of inside beams can be simplified.