Triage methodology of bridges for infrastructure management: empirical analysis of road networks in municipalities with declining populations and increasing debts

Abstract

The population of Japan peaked in 2010 and has since entered a depopulation period. On the other hand, there are many bridges that were constructed in the past, especially during the period of high economic growth. Their deteriorating state is becoming increasingly evident. It is expected that maintenance and management costs of the development and maintenance of urban infrastructure for bridges will increase. It is necessary to respond to the ageing of the national land stock. This study verifies urban infrastructure methodology to develop and maintenance using a road network of a municipality whose population actually decreases. This methodology makes use of the basic data held by the municipality such as the population and the length of the road. More specific, the authors propose a methodology for applying the triage to the decision-making processes involving bridges such as road bridges, similar to how it is applied when providing medical care to those with injuries caused by large-scale disasters. The proposed methodology is useful for municipal bridge management strategy and can be applied to other countries around the world that may face decreasing population and/or rising debt in the future.