Health assessment and self-powered corrosion monitoring system for deteriorated bridges

In Hokuriku, a snowy and frosty region located in the northwestern part of the main island of Japan, chloride attack, alkali-silica reaction (ASR), and frost damage are the causes of the premature degradation of many bridges without warning. Therefore, it is very important to identify the main cause of deterioration to plan the maintenance works. This study conducted a structural health assessment for an elevated line on the Hokuriku Expressway to evaluate the functional value of the target structure. Polarizing microscope observation of the specimens collected from the target slab confirmed that chloride attack was the main cause of the deterioration, and ASR was not detected. The reduction in the stiffness and load-bearing capacity of the objective bridge due to chloride attack was also studied and reported by comparing the result obtained from the vehicle running tests and numerical analysis. Long-term monitoring of the responses of the objective bridge due to moving load based on bridge weigh in motion (BWIM) was also evaluated for ordinary vehicles. Further, a steel corrosion mitigation method using a detachable sacrificial anode attached to the lower surface of the slab was applied. To contribute to efficient structural health monitoring approaches, a self-powered remote-monitoring system using a vibration energy harvester is introduced to the target bridge.