Design optimization of noise barrier tunnels through component reuse: Minimization of costs and CO2 emissions using multi-objective genetic algorithm

Abstract

Reuse is known to be an effective method to increase the sustainability of the architecture, engineering, and construction industries, which account for a majority of CO2 emissions and waste generation. However, despite the environmental benefits involved, additional costs and increased design difficulty limit the application of reuse. This paper proposes an optimal design method that minimizes the CO2 emissions and costs of the noise barrier tunnel. In the proposed method, information on reusable steel beams from the building information modeling data of the noise barrier tunnel is extracted, and the optimization problem is defined. In addition, designs and component procurement plans aiming to minimize CO2 emissions and costs are derived using a multi-objective genetic algorithm. The results of the case study show that depending on the situation, CO2 emissions are reduced from 1% to 92% and costs are reduced by up to 25% relative to the case without reuse. As in previous studies, CO2 emission could be reduced herein through reuse, but an increase in costs was observed in some cases. This study contributes to the literature by providing optimal alternatives for designers through an optimal design method integrating strategies to overcome barriers to the practice of reuse. The case study results also highlight the need for an assessment through the entire life cycle, including the modification and inspection processes of reusable components that are generally excluded.