A Framework for Optimizing Lap Splice Positions within Concrete Elements to Minimize Cutting Waste of Steel Bars

Abstract

One of the material waste streams in the construction of concrete structures is the waste generated during cutting of steel bars to their final required length. The amount of waste generated to produce the required length of steel bars can be affected considerably by the cutting patterns adopted. Waste can, therefore, be minimized by optimizing the cutting pattern to be selected. Cutting patterns are a combination of bar lengths and, thus any change in the required lengths directly affects cutting patterns and the final amount of waste. This paper presents a framework for selection of the location of lap splices, through generating all possible lapping patterns, which define the bar lengths in cutting patterns. The focus is placed on steel bars used in concrete columns as their arrangement is affected by multiple parameters that make the manual preparation of shop drawings a tedious job. The developed framework is applied to a case study involving the construction of columns for an actual 6 storey building. The estimated waste produced after the adoption of optimal lapping patterns is compared with the actual waste generated based on the project shop drawings. The results indicate that considerable reduction in the steel bars wasted is achievable by optimizing the lapping patterns.

Estimation and Minimization of Embodied Carbon of Buildings: A Review

“…Yeo and Gabbi showed that the structural optimization of a beam cross section can result in a decrease in the embodied energy of the beam on the order of 10% at the expense of about a 5% increase in the cost relative to a cost-optimized member. The total amount of materials used in a structure, and thus the embodied carbon of the structure, has also been shown to be considerably affected by the amount of waste produced during component manufacturing, on-site construction and installation process [76,77]. Therefore, minimizing the waste generated during production and construction can be considered a potential strategy for minimizing the embodied carbon of structures.…”

“…Therefore, minimizing the waste generated during production and construction can be considered a potential strategy for minimizing the embodied carbon of structures. Moussavi et al showed through a case study that minimizing the trim loss in cutting reinforcing steel rebars resulted in a decrease of about 7.7% and 49.6% in the total amount of material used and generated waste, respectively [76].…”

Near-Zero Rebar Cutting Waste Management by Adjusting Lap Splice Position

“…Rebar cutting waste (RCW) is generally estimated to be 3-5% in the construction planning stage [1][2][3][4]. However, technology to reduce RCW was not developed at the construction field, so more than 5% is generated in the actual construction [5][6][7][8][9]. To solve this problem, many studies was conducted to minimize RCW [10][11][12][13][14].…”

“…Kwon, K. et al, (2021) stated that the rebars amount used in the world was 947 million tons in 2019, and assuming RCW ratio of 3 to 5%, global RCW of 2841~47.35 million tons are generated annually [17][18][19]. And the study stated that if 0.3416 ton•CO2/ton [20] of CO2 emission from rebar is applied, about 971~16.18 million ton of CO2 emission is calculated.…”

Cutting Waste Minimization of Rebar for Sustainable Structural Work: A Systematic Literature Review

“…Over the past few decades, numerous studies have been conducted on minimizing cutting wastes, and various optimization algorithms have been proposed. However, in reality, cutting wastes are still generated in the process of cutting and bending of rebars, which are at least 3% to 5% [3][4][5][6][7], and as much as 5% [4,[6][7][8][9][10][11] to 8% [12], compared to the volume shown in the structural drawings.…”