Life-Cycle Cost Analysis of a Viaduct Considering Uncertainties on the Interventions Plan

Life-Cycle Analysis is usually referred to as the assessment of a system that includes the three pillars of sustainability, i.e. economic, environmental, and social aspects. Many works have been developed presenting and discussing methodologies and frameworks to include the evaluation of these aspects. In general, economic performance is the most addressed, followed by the environmental aspect. A highly generalized formulation is usually used regarding social aspects since it corresponds to the society at large. The present work is focused on the economic aspects of the assessment, implementing a life-cycle cost analysis methodology to an infrastructure system (viaduct) covering all direct costs for agency/owners. Furthermore, to indirectly account for climate changes, and the requirements of the quality control plan (QCP) for operational issues, a semi-probabilistic approach is carried out. The life cycle cost analysis assumes a uniform probabilistic distribution for the intervention time of maintenance and rehabilitation activities. With this, variations in the degradation processes due to climate changes and/or intervention needs to fulfill requirements from QCP, are considered. For this purpose, the time at which each intervention might occur in the future is assumed as a random variable. Monte Carlo simulation is then used to compute the cost of several different scenarios. On other hand, the present work provides another approach referred as the deterministic approach. It estimates the life cycle costs deterministically, and considers at the end of the analysis the uncertainties associated with the life-cycle process in a rough way assuming a general coefficient of variation of ±20%. The main goal of this work is to understand the impact that uncertainties in the intervention schedule might have on the final life-cycle cost.