Long-term maintenance strategies for highway bridges

The need for cost-effective maintenance strategies for highway bridges is becoming increasingly important as these structures age and the demands for funding expand. Shortfalls in the annual budget to complete all the identified work also requires that rational procedures be formulated regarding when maintenance work on different structures within a stock should take place. Two main types of maintenance are considered: steady state and essential. The concept of an optimal maintenance programme is introduced. In most cases this is the ideal situation since it minimises long-term costs and disruption to users of the structures. In practice, optimal maintenance strategies may not be affordable when first introduced if there is a backlog of work resulting in a need to prioritise parts of the work. Prioritisation is discussed in terms of quantifying the consequences of deferring maintenance work, and ranking the bridges in the stock by their value of cost: benefit ratio of deferring the work. The use of a long-term plan to eliminate maintenance backlogs that arise from long-term underfunding is explained and the ‘long-term plan formula’ is introduced. A flow chart is provided to prioritise the maintenance on bridges included in a long-term plan.