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

Rachmawati, Titi Sari Nurul; Khant, Lwun Poe; Lim, Jeeyoung; Lee, Jeongsun; Kim, Sunkuk

doi:10.1080/13467581.2023.2278881

Cited by 6 publications

(38 citation statements)

References 22 publications

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“…Cutting patterns have been optimized in stock length rebars to reduce unusable rebar waste in multiple studies [1,17,23,24,25]. These approaches, however, did not achieve rebar wastage less than the common range of 3-5% [10,26], since their optimization was restricted to the lap splice position regulations mandated by the building codes [20]. Using stock-length rebars reflecting those regulations results in limited flexibility and potential material waste.…”

Section: Related Literaturementioning

confidence: 99%

“…Recent studies [11,20] utilized special length rebars to minimize rebar waste in beams and diaphragm walls. Widjaja and Kim [11] minimized rebar consumption and cutting waste in beam members by a two-stage optimization algorithm using special length and achieved 0.93% rebar cutting waste.…”

Section: Related Literaturementioning

confidence: 99%

“…Widjaja and Kim [11] minimized rebar consumption and cutting waste in beam members by a two-stage optimization algorithm using special length and achieved 0.93% rebar cutting waste. The study by Rachmawati et al [20] also resulted in near-zero rebar cutting waste by 0.77% in reducing cutting waste of diaphragm wall rebars by a three-step heuristic algorithm, considering the special length and the flexibility of lap splice position. It has been sufficiently proved that special length prioritization over stock length offers a significant reduction in rebar waste.…”

Section: Related Literaturementioning

confidence: 99%

“…As shown in Figure 1, the current practice of preparing BBS relies on extracting information from 2D computer-aided design (CAD) drawings or paper-based shop drawings [15,30], which often leads to wrong interoperation and deficits of wrong input via manual tasks, consequently, results in miscalculations of exact rebar quantities Recent studies [11,20] investigated the extraction of BBS from BIM models for rebar optimization. However, this approach can inherit inaccuracies from the initial BBS, leading to suboptimal and potentially inaccurate rebar selection due to data inconsistencies.…”

Section: Research Objectivesmentioning

confidence: 99%

“…Multiple research projects have been conducted on rebar waste optimization on columns [17,18]], beams [11,19], and diaphragm walls [20], which are the main structural members in the construction. Among them, diaphragm walls consume an enormous amount of rebar, as well as require diverse types of rebar for different purposes in fabrication, including links, stiffeners, spacers, fixing rebars, suspension hooks, starter bars, etc.…”

Section: Introductionmentioning

confidence: 99%

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A BIM-Based Bar Bending Schedule Generation Algorithm With Enhanced Accuracy

Khant,

Widjaja,

Kwon

et al. 2024

Preprint

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Rebar quantity estimation is pivotal for determining the cost of construction projects and essential for bidding purposes. A bar bending schedule plays a crucial role by providing rebar information and bending instructions, facilitating efficient procurement. Traditional methods of bar bending schedules, which involve manual extraction from 2D (two-dimensional) drawings, are error-prone and hinder construction productivity. This study proposes a Building Information Modeling (BIM)-based algorithm that automates the generation of a Bar Bending Schedule (BBS) directly from the 3D (three-dimensional) BIM models, ensuring accuracy and eliminating manual errors. The effectiveness of the algorithm was verified by comparing the rebar quantities generated by the model against those derived from optimization calculations. The results demonstrated a mean absolute error of 0.017 and a mean absolute percentage error of 1.13%, validating the algorithm’s precision. Additionally, it achieved a remarkable 33.33% reduction in the manpower required for preparing BBSs, highlighting its potential to revolutionize construction workflow efficiency and accuracy.

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Section: Related Literaturementioning

confidence: 99%

Section: Related Literaturementioning

confidence: 99%

Section: Related Literaturementioning

confidence: 99%

Section: Research Objectivesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A BIM-Based Bar Bending Schedule Generation Algorithm With Enhanced Accuracy

Khant,

Widjaja,

Kwon

et al. 2024

Preprint

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Optimization of Rebar Usage and Sustainability Based on Special-Length Priority: A Case Study on Mechanical Couplers in Diaphragm Wall

Widjaja,

Khant,

Kim

et al. 2023

Preprint

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The construction industry generates significant CO2 emissions, and rebar is a major contributor to this environmental impact. Extensive research has been conducted to address this issue. Recent advancements have introduced algorithms to reduce rebar waste and consumption, demonstrating the feasibility of achieving near-zero rebar cutting waste (N0RCW) by considering special-length rebars. However, conventional lap splices, the most common rebar joint method, consistently consume excessive rebar quantities despite extending beyond their mandated zones. Conversely, couplers eliminate rebar lengths required for lapping splices, reducing the usage of rebar. Applying special lengths and couplers in heavily loaded structures like diaphragm walls can significantly reduce rebar usage and cutting waste, consequently reducing CO2 emissions and associated costs. This study aims to optimize rebar consumption and sustainability in diaphragm wall structures by integrating mechanical couplers with a special-length rebar approach. A case study confirmed a substantial reduction in purchased rebar usage (17.95% and 5.38%) and carbon emissions (15.24% and 2.25%) compared to the original design and previous study, respectively. Broadly implementing the proposed method across various buildings and infrastructure projects could further multiply these benefits, fostering the achievement of SDGs adopted by the United Nations for sustainable construction.

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Data-Driven Approach for Selecting Mechanical Rebar Couplers Based on the Shape and Structural Characteristics of Reinforcing Bars for Sustainable Built Environment

Lim,

Kim

2024

Preprint

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In reinforced concrete (RC) structures, splicing is required owing to the length limitations of rebars, insufficient lengths, and transportation issues. In particular, splices connect the rebar of RC structures such as walls, columns, beams, slabs, and joints. Lap splices are the most commonly used method worldwide because they do not require specific equipment or skilled workers. However, lap splices incur high construction costs because of the long splice lengths required for large-diameter rebars in megastructures, as well as issues pertaining to material supply, labor costs, constructability, and project duration. Additionally, approximately 15% more rebar is required because of the overlap. Energy saving for a sustainable built environment is possible if the disadvantage of lap splices, which generate high CO2 emissions due to the excessive use of rebar, are resolved. Hence, mechanical rebar couplers (MRCs) have been developed. However, despite their advantages, they have not been widely applied in construction sites owing to concerns regarding safety, quality, and constructability. Although various MRCs have been developed, most studies focus only on their structural performance. Therefore, a data-driven approach for selecting MRCs based on the reinforcing bar shape and structural characteristics is proposed in this study. Using a data-driven MRC selection algorithm, using the T-threaded coupler for one rebar over two floors resulted in 56% more efficient labor productivity, 15% shorter assembly time, 17% lower costs, and 26% lower CO2 emission. Using a developed algorithm, the appropriate MRC can easily and rapidly be selected for frequent design changes.

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

Cited by 6 publications

References 22 publications

A BIM-Based Bar Bending Schedule Generation Algorithm With Enhanced Accuracy

A BIM-Based Bar Bending Schedule Generation Algorithm With Enhanced Accuracy

Optimization of Rebar Usage and Sustainability Based on Special-Length Priority: A Case Study on Mechanical Couplers in Diaphragm Wall

Data-Driven Approach for Selecting Mechanical Rebar Couplers Based on the Shape and Structural Characteristics of Reinforcing Bars for Sustainable Built Environment

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