Predicting the failure of timber bridges by using current inspection reports

There is a large timber bridge stock in service within Australia and currently over 300 timber bridges on Queensland state controlled roads. Majority of these timber bridges are in the latter half of their service life and require constant maintenance as the timber components deteriorate over time. Detailed level 2 inspections are performed as part of the bridge management systems used by road authorities. This paper discusses a simple method to use an inspection report to predict the chance of the failure of the bridge in a given number of years. Although the Markov process adopted in this research was based on inspection reports for several timber bridges for three time periods, it can further be refined using a data base of inspections for many time periods and environmental conditions. The proposed method is demonstrated using an inspection report for a hypothetical timber bridge