ABSTRACT
Tokyo Metro Co., Ltd. maintain over 195.1km structures, so our maintenance should be efficient, effective and persuasive for stakeholders. General inspections of tunnels are composed with visual test and hammering test, which determines grades of structural health related to defects. However, it is quite difficult to grade the health equivalently through an entire tunnel because inspections are conducted by human. Moreover, each renovation work is prioritized by experienced employees based on their intuition. To address this issue, we developed an inspection item response model, a mathematical model. In this model, various inspection data is analyzed to calculate maintenance indicators which quantify the health grades of each section of tunnels. This report presents an overview of the maintenance indicator as well as the process, results of those estimations and undertaking of future.
