An Inventory Theory Model to Determine the Optimal Work Program for Bridges

摘要

The bridges included in the work programs of many bridge management systems are those that have at least one element that requires an intervention according to the element level intervention strategies to be followed. The work suggested on the other elements is often determined using agency rules, e.g. if an intervention is to be performed on the bridge and element x is in condition state y execute intervention z even if the intervention strategy to be followed for element x does not require it. One of the reasons this is done to ensure that there is a significant amount of time between the executions of interventions on the bridge, which indirectly helps to keep the costs due to multiple interventions low. Although the grouping of interventions in this way most likely reduces the costs of multiple interventions it does not do so in an optimal way. In this paper a methodology to optimally bundle element level interventions to build work programs is investigated. The methodology is based on an initial concept proposed by (Adey and Hajdin 2005) but extended in numerous ways to deal with real world applications. The methodology is demonstrated using a steel bridge, composed of 4 key elements. The work programs built through grouping interventions using the investigated methodology and those built without grouping are compared. It is shown that the WP built by grouping element level interventions using the investigated methodology can result in lower costs than those built without grouping.