Optimal long-term scheduling of bridge deck replacement and rehabilitation

A mixed-integer mathematical model is presented to optimally schedule long-term bridge deck rehabilitation and replacement activities. This model is applicable to multiple bridge decks and is driven by overall cost considerations. Activities are scheduled based on the current condition and perceived future deterioration of each bridge deck. The model uses logical constraints to incorporate an ‘if-then-else’ scenario into the rehabilitation model. These constraints directly relate the maintenance decisions in any year to the perceived condition of each individual bridge deck. Model structure and solution method were discussed, and an example using three highway bridges in North Carolina is presented. Model solutions indicate bridge deck replacement and rehabilitation activities throughout the planning horizon for each deck considered. Model results include the development of a trade-off relationship between long-term costs and the level of deterioration at which a bridge deck is replaced.