Abstract
This paper highlights the importance of the model of the deterioration process of the concrete bridges and its significance in the bridge management and the development of the factor method. The most common types of damages caused by the deterioration included minor cracking, major cracking, spalling and service failure and the cost ranged from millions to billions. The rate of deterioration of Foot Bridge and over bridge and their members were examined. The rate was higher in Footbridge as compared to overbridges. The main reasons were use of the structure, construction type and exposure conditions. Various types of predictive models mainly deterministic and probabilistic approach were reviewed which includes Markov chain model, regression model & Factor method. The analysis suggested the factor method was most comprehensive among others. The factors considered in modelling were of two approaches: deterministic and probabilistic.