BRIDGIT deterioration models

Accurate prediction of the future condition of bridge elements is one of the cornerstones of any bridge management system's (BMS's) optimization model. The BRIDGIT BMS software uses condition state quantities to represent the conditions of the various elements that make up a bridge. The use of condition states does not allow for an easy application of classical deterministic deterioration curves. It is necessary to model the transition of element quantities through their various condition states. Predicting the deterioration of an element through time is essential for estimating the timing of future repair and improvement actions and calculating their associated costs. Deterioration of a bridge element can be represented by a Markov chain process. By this approach transitional rates are calculated to project the quantities of a bridge element that will move to lower condition states in a defined time interval. BRIDGIT uses derivatives of Markov chain processes to model unprotected elements, protection systems (such as paint systems or deck overlays), and protected elements in which the protection system modulates the deterioration of the base element. In addition, BRIDGIT considers the effects of environment, traffic volumes, and previous repairs that may accelerate the deterioration of decks, slabs, and overlays.