Multi-objective optimization for selecting potential locations of multi-purpose utility tunnels considering agency and social lifecycle costs

Abstract

Multi-purpose utility tunnels (MUTs) and the synchronized method of underground utility intervention are two methods that have the potential to reduce the maintenance intervention lifecycle cost (LCC) of underground utilities. However, when considering the total LCC of both methods, there is a tradeoff between agency and social costs. Currently, limited research quantifies the socioeconomic impact of both methods at a macro level, especially the long-term benefits of MUTs. By quantifying the socioeconomic impacts of implementing both MUTs and the synchronized utility interventions at the network level, the LCCs of both alternatives can be optimized and compared. The main objective of this research is to optimize the agency and social LCCs and network deterioration using multi-objective optimization for identifying the potential locations of MUTs. This selection involves modeling the agency and social cost savings and the network deterioration resulting from the implementation at the network and segment levels. Comparing the optimization results in identifying the street segments in a network where the LCC of implementing MUTs is less than the LCC of the synchronized utility intervention. While doing so, a multi-year plan for MUT location selection that optimizes the three objective functions and offers lifecycle savings is achieved. The results show that out of the 312 potential street segments selected for MUT implementation, 51 offered both agency and social LCC savings. This research can aid utility owners in understanding the socioeconomic effects of both methods of utility interventions as well as identifying streets where the implementation MUTs will have significant economic advantages.