Markovian Bridge Maintenance Planning Incorporating Corrosion Initiation and Nonlinear Deterioration

Abstract

For some materials, such as RC, there is an initiation phase of deterioration where aggressive agents such as chlorides diffuse into the concrete cover. It is necessary to model this initiation time when attempting to determine the optimal maintenance strategy for the lifetime cost associated with a structure. It has been recommended in the literature that Markov chain models should be further improved within maintenance management systems to take initiation time into consideration. Many existing bridge management systems (BMSs), such as BRIDGIT and Pontis, use Markovian-based maintenance management to simulate the propagation phase of deterioration and repair of structures over time. It is therefore useful to continue this progress through incorporation of an initiation phase in relation to the development of Markovian-based maintenance management, which can lead to an improvement in BMSs that are already in place. The incorporation of the initiation phase into deterioration modeling can affect the frequency of inspections, repairs, and failures and hence the expected cost over the remaining lifetime of the structure. On this basis, this issue was addressed as part of this study. A maintenance management model has been further developed to take this two-step deterioration process (i.e., initiation and propagation) into account. This allows owners/managers of bridges to compare the efficiency of different maintenance strategies in terms of both the initiation phase and the propagation phase of deterioration to determine the optimal maintenance strategy for the structure or group of structures being considered. The capabilities of the developed methodology are demonstrated using a practical example.