Survival analysis on bridges for modeling bridge replacement and evaluating bridge performance

Abstract

A sustainable civil infrastructure is a prerequisite for achieving sustainability in infrastructure development. However, the finite lifetime of infrastructure indicates a latent mass-maintenance problem in some countries which had experienced mass-construction of infrastructure during high economic growth. To achieve optimal infrastructure management for overcoming this mass-maintenance problem, life prediction of infrastructure is indispensable. Hence, in this research, bridge life assessment from actual bridge survival data from the United States and Japan was carried out by using the method of survival analysis, a method commonly applied in the field of epidemiology for the analysis of lifetime. The results estimated average bridge life at 93.5 years and a bridge replacement projection model was successfully derived. The bridge replacement projection model can be applied as an approximation for other countries where the same design specifications are followed. By carrying out stratifications of bridge cohorts in the United States, evaluations of bridge performance with respect to structure length; traffic volume and truck traffic volume were also executed.