Short-Span Bridge Management Based on Safety Evaluation from Early Stage

Abstract

Among the 700,000 existing Japanese bridges, many were deemed to necessitate repair as a result of bridge inspection. However, Japanese municipalities do not have sufficient time or budget resources, which limits the potential for bridge maintenance and repair. Almost all the bridges managed by municipalities are short-span bridges. This work proposes a maintenance policy for bridge repair based on evaluation of safety. However, ongoing bridge maintenance policy in Japan based on bridge conditions, and not on safety. To alleviate this, we propose an approach which, in addition to preventive and corrective maintenance, applies observational maintenance, and a quantitative performance evaluation during the early stages of deterioration. The proposed structure reduces the number of repair targets by periodically evaluating performance using quantitative data. The data used for the performance evaluation are obtained using a method that can be implemented simultaneously with bridge inspections, so as not to place additional burden on time and budget. Electromagnetic wave and fluorescent X-ray method, impact-echo monitoring with machine learning, internal diagnosis of concrete using a thermal imaging camera and 3D diagnosis of deterioration are incorporated as methods to detect performance changes at an early stage. This paper shows the summary of the case studies, the structure of the proposed method, and reports on the obtained effects.