Sustainable design of reinforced concrete structural members using embodied carbon emission and cost optimization

Abstract

Sustainable structural designs are gaining increasing attention in light of the green development of the building industry. Recent research was conducted on various reinforced concrete members, whereas these studies mainly aimed at the material production phase using a single-objective optimization algorithm. In this context, the present study adopted a multi-objective genetic algorithm for the sustainable design of reinforced concrete members, according to the embodied emissions and costs. A comprehensive system boundary was defined which covered the production, transportation, and construction phases, with respect to subprojects of reinforcement processing, concrete casting, and formwork. Based on the proposed method, a numerical example was investigated to compare the Pareto optimal solutions for singly-reinforced and doubly-reinforced concrete beams. With a comparison of the most “carbon-friendly” and “cost-friendly” solutions, the results indicated that an added cost of 5–6% can contribute up to a 14.7% emission reduction. Moreover, detailed parametric analyses were made to explore the main factors for sustainable beam designs. The results demonstrated the influences of sectional dimensions, steel and concrete strengths, emission factors, and the environment on the sustainable design, according to the minimum emission and cost optimization. Overall, the present study can help understand the optimization algorithm of sustainable structural members and the relevant design factors, from a comprehensive perspective of both the emissions and the costs.