Optimization of lap splice positions for near-zero rebar cutting waste in diaphragm walls using special-length-priority algorithms

Abstract

ABSTRACT Construction processes often result in rebar waste when cutting stock length rebar to required length, incurring significant costs and contributing to CO2 emissions. While prior research has explored rebar waste reduction through cutting pattern optimization, the potential gain from adjusting lap splice positions has been neglected. This study focuses on enhancing waste reduction by optimizing lap splice positions, particularly focusing on utilizing special length rebar to achieve a cutting waste rate below 1%. Our approach employs a three-step heuristic algorithm: (1) optimizing lap splice positions for alignment with special length rebar; (2) generating cutting patterns based on special length rebar; (3) creating cutting patterns for remaining rebars using stock length rebar. Applying this algorithm to a diaphragm wall at an interchange station adhering to the British Standard shape codes yielded remarkable results. The cutting waste decreased by 3,000.22 tons, the CO2 emissions reduced by 10,398.77 tons, and the cost savings totaled USD 3,480,108. Consequently, the cutting waste rate reached an impressive 0.77%. By adopting the principles outlined in this paper, construction practices can significantly reduce waste, promote sustainability, and mitigate financial losses associated with rebar waste.