Assessing Serviceability Improvement Alternatives of Existing Structures

The aim of this paper is to present a generic decision support system for selecting an optimal repair alternative for aging infrastructure systems considering sustainability. Emphasis is placed on how to properly decide on a maintenance, repair, rehabilitation, replacement strategy for deteriorating structures, applying the concept of life-cycle cost analysis. Taking into account the decision timing and repair costs of each alternative, an incremental annual uniform cost (IAUC) method is proposed to compare various levels of repair strategies and to reach a rational decision based on the proposed Economic Index (EI). On the sensitivity study of the model, it is concluded that the discount rate has minor impact on the selection and the repair timing is crucial to a successful saving. A priority ranking of repair alternatives can be identified once the deterioration model is defined, and the decision timing and repair cost are input. The proposed methodology provides engineers and owners with a quantifiable solution at project level for selecting repair alternatives with very minimal input information required.