Preventative maintenance (PM) is a planned strategy of cost-effective treatments to an existing roadway system and its appurtenances that preserves the system, retards future deterioration, and maintain or improve the functional condition of the system (without substantially increasing structural capacity).
Bridge owners typically apply PM to elements or components of structures with significant remaining useful life. As a major part of bridge preservation, PM is a strategy of extending useful life by applying cost-effective treatments to sound bridges (good or fair condition). The concept of preventative bridge maintenance suggests that a planned strategy of cost-effective treatments should be performed to keep bridges in good condition, retard future deterioration, and avoid large expenses in bridge reconstruction or replacements.
Bridge element or component conditions are not always directly improved as a result of these activities, but deterioration is expected to be delayed.