• 한국건축시공학회지
• /
• 제23권4호
• /
• pp.497-508
• /
• 2023

Manual estimation of rebar quantities by contractors often yields discrepancies between projected and actual amounts used in the construction phase, leading to cost inaccuracies and potential logistical challenges. To address these issues, there is a clear need for a method that allows precise estimation of rebar quantities during the design phase. Such a method would enhance contractor competitiveness during project bids, promote accurate cost calculations, and avert superfluous rebar purchases on-site. Given that columns are the primary structural components in reinforced concrete(RC) buildings and necessitate considerable amounts of rebar, this study focuses on creating an automated algorithm for estimating column rebar quantities. An analysis of the accurate quantities obtained via the study and those derived from manual estimation reveals a discrepancy of 0.346 tons or 2.056%. This comparison affirms the proposed algorithm's efficacy in eliminating errors from overestimation or underestimation of rebar quantities. The practical implications of this study are significant for construction companies as it fosters efficient and precise estimation of rebar quantities, ensuring compliance with related specifications and governing regulations.

• 한국건설관리학회논문집
• /
• 제24권5호
• /
• pp.83-94
• /
• 2023

In order to devise a rebar usage optimization algorithm, it is necessary to calculate the exact rebar length and revise the arrangement of rebars into special lengths. However, the process of rearranging numerous rebars and manually calculating their quantities is time-consuming and requires significant human resources. To address this challenge, it is necessary to develop an algorithm that can automatically estimate the length of rebars and calculate their quantities. This study aims to create an automatic estimation algorithm that improves work efficiency while ensuring accurate and reliable calculations of rebar quantities. The algorithm considers various factors such as concrete cover, hook length, development length, and lapping length, mandated by the building codes, to calculate the quantity of rebars for wall structures. The effectiveness of the proposed method is validated by comparing the rebar quantities generated by the algorithm with manually calculated quantities, resulting in a difference rate of 1.14% for the hook case and 1.37% for the U-bar case. The implementation of this method enables fast and precise estimation of rebar quantities, adhering to relevant regulatory codes.

• 한국BIM학회 논문집
• /
• 제14권3호
• /
• pp.13-21
• /
• 2024

This study aims to simplify the rebar quantity estimation process during the detailed design stage of buildings by addressing identified issues in the existing rebar quantity estimation process and establishing a BIM-based simplification method. To validate the applicability of the proposed method, it was applied to a case study of 'K' High School, with the results compared to rebar quantities from shop drawings to assess usability in real projects. It showed an error rate of 1.4% for SHD22S and 2.63% for HD10 among the types of rebar used in the case model. SHD22S, used as the main rebar in the columns, exhibited this error due to differences in the calculation method for splice and anchorage lengths. HD10, used as stirrup rebar in the columns, showed errors due to the omission of hook length considerations in the simplified estimation formula. Although these discrepancies resulted in cumulative errors of 10 to 20 meters, the error rates of 1.4% and 2.63% respectively fall within the generally accepted rebar overage rate of 5%, suggesting that this method is sufficiently accurate for quantity estimation during the detailed design stage. This study presents a method for efficiently estimating rebar quantities based on BIM during the detailed design stage. While traditional 2D quantity estimation and BIM-based methods often suffer from inefficiencies due to repetitive tasks and high modeling complexity, the proposed method assumes BIM models at LOD200, which are less complex and automate most of the structural information required for rebar quantity estimation, thereby reducing repetitive tasks. However, to further minimize errors, especially those related to hook and anchorage length calculations, additional research is needed to refine the estimation process and expand its applicability to the entire building's rebar quantity estimation.

• 토지주택연구
• /
• 제8권4호
• /
• pp.257-266
• /
• 2017

LH has been using ultra high strength reinforcing bars (SD500 and SD600), since 2011. Such a change requires an adjustment of the old extra rates of bar splice to reflect use of ultra high strength reinforcing bars, as these rates had been set based on SD400 bars. It is particularly difficult to calculate precisely rebar lap-splice locations for large areas, such as those in apartment buildings. This research aims to adjust the extra rates of bar splice to reflect a reasonable rate; the rebar lap-splice length is not an exact estimation, but instead, an extra rates of bar splice is set and the rebar lap-splice length is increased by 2% (D 10) - 7% (025) depending on the bar size. The subjects of this study are LH apartments undergoing frame construction. We studied the quantity estimations from the design drawings, and analyzed the settlement quantities of construction field. The results of the study revealed that, when each of the quantities are analyzed, consider adjusting the extra rates of bar splice of some rebar to 1% - 3.5%. This was caused by an overuse of reinforcing bars in onsite construction and the use of supporting bars that have not been reflected in the documents, among other reasons. Based on the results of our study, an improvement plan for the current extra rates of bar splice seems to be necessary, cutting or raising the rate depending on the analysis of the data. Through this study, we expect to contribute to the calculation of reasonable construction costs, improvements in the quality of rebar work, and improvements in the capacity of design techniques for apartment buildings.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2002년도 학술.기술논문발표회
• /
• pp.133-138
• /
• 2002

Rebar work takes up big proportion in a construction work. The current process of purchasing, cutting and election, and working of rebar induces a lot of loss in rebar. This study is focused on analyzing the problem and the present condition of the process from the calculating of rebar quantifies to the actual constructional stage through surveying those who have experience in the estimation department, or the construction site of a domestic construction company. Many reform measures such as diversification of standard(i.e., 8-meter)bar, calculation of rebar quantities and construction according to the rebar election drawing, expansion of accuracy in layout plan, thoroughness in examination of layout plan in advance, utilization of the worked material, systemization of rebar control(management), and a shift in attitude of the field(site) manager were proposed as the result of the survey.

• 한국건축시공학회지
• /
• 제13권3호
• /
• pp.291-305
• /
• 2013

This paper presents the continuous hoop reinforcement method as a means to overcome the difficulty of rebar construction due to the seismic detail of lateral reinforcement. Because the continuous hoop has no seismic hook, and there is less interference during the rebar work, rebar quantities and construction time can be reduced. Since the details of column and beam continuous hoops are different from those of conventional lateral reinforcements, the construction method should be developed through mock-up tests. The length of the beam mock-up is 8m and the section size is $500mm{\times}700mm$, the height of the column mock-up is 2.8m and 4m, and the section size is $800{\times}800mm$. The length and the size are determined based on the elements that are generally used in reinforced concrete basement parking lots and office buildings. The results of the mock-up test showed that the quantities of rebar could be reduced by 20% and the time could be reduced by up to 40% compared with conventional lateral reinforcements.

• 한국건축시공학회지
• /
• 제5권4호
• /
• pp.99-106
• /
• 2005

With labor shortage and high-wage, the construction cost is rising and the construction-business is dull, demanding the construction environment of Korea to raise profitability through major cost savings and rationalization of construction management. Therefore, in this study, to improve many problems found in calculating rebar quantity for capital expenditure programming which is considered the beginning stage of rebar work. and to improve problems such as no grasping of rebar loss due to lack of systematic management in order/purchase stage and construction management stage, a rebar information-management-system was found and preyed. The relation database was designed for the rebar information management system by analyzing work process of a rebar manufacturing plant, as the rebar information that is necessary in a rebar manufacturing plant if similar to that of a purchasing department of general construction company. The Proposed rebar information management system was implemented in two large rebar production plants. The implementation of the proposed system showed that the system increased work efficiency, reduced the management manpower, and improved the project-integrated management

• 한국건축시공학회지
• /
• 제23권4호
• /
• pp.485-496
• /
• 2023

Precise construction cost estimation is paramount to determining the total construction expense of a project prior to the initiation of the construction phase. Despite this, manual quantification and cost estimation methods, which continue to be widely used, may result in imprecise estimation and subsequent financial loss. Given the fast-paced and efficiency-demanding nature of the construction industry, trustworthy quantity and cost estimation is essential. To mitigate these obstacles, this research is focused on establishing an automated quantity estimation algorithm, particularly designed for the main rebar of beams which are recognized for their complicated reinforcement configurations. The exact quantity derived from the proposed algorithm is compared to the manually approximated quantity, reflecting a variance of 10.27%. As a result, significant errors and impending financial loss can be averted. The implementation of the findings from this research holds the potential to significantly assist construction firms in quickly and accurately estimating rebar quantities while adhering strictly to applicable specifications and regulatory requirements.

• 한국건설관리학회논문집
• /
• 제24권5호
• /
• pp.52-62
• /
• 2023

본 연구의 목적은 정착 길이, 표준 후크 및 이음 길이와 같은 관련 규정을 준수하면서 슬래브 철근의 정확한 절단 길이를 산출하는 자동화된 알고리즘을 제안하는 것이다. 제안된 알고리즘은 일반적으로 외주를 통해 수작업으로 진행하던 기존 철근 물량 산출 프로세스를 개선하는 것을 목표로 한다. 입찰 단계부터 정확한 철근 수량 데이터를 BBS(Bar Bending Schedule) 수준으로 제공함으로써 물량 산출의 불확실성을 제거하고 외부 의존도를 낮출 수 있다. 또한, 알고리즘을 통해 정확한 물량을 조기에 산출하는 경우 건설사는 경쟁력 있고 최적화된 입찰을 미리 준비할 수 있어 계약 협상 시 이익률을 높일 수 있다. 제안된 알고리즘은 견적, 예산, BBS 생성 등 다양한 프로세스에서 중복되는 업무를 간소화할 뿐만 아니라 계약 후 구조 도면 변경에도 유연하게 대처할 수 있다. 특히, 제안된 알고리즘을 BIM과 결합하는 경우 시공 초기 단계에서 BIM을 적용할 때 발생하는 기술적 문제를 해결할 수 있으며, REVIT 기반 패밀리 파일로 구축된 알고리즘의 수식과 형상 코드는 실무에서 상당한 시간과 인력 절감에 기여한다.

• 한국건축시공학회지
• /
• 제9권2호
• /
• pp.39-46
• /
• 2009

The erection bar is defined as the assistant bar used to fix the position of the reinforcing steel as the reinforcing steel is placed on site. As the erection bar do not bear the structural load and is not showed in the structural drawings, it is not managed importantly. But as chair bars in mat footing is used in large quantities to support the upper main bars, the detailing standards need to be suggested. and some erection bar is placed by experience of the fabricator and placer. Therefore, in this study, a survey about the erection bars was conducted to the reinforcement detailer, the fabricator and placer of domestic construction industry. 11 placing drawings is analyzed to find out the problems of detailing and the quantities of the erection bars. According to the analysis of the survey, the erection bar details in placing drawings were not standardized, and some erection bars are omitted in placing drawings. The improvement in the erection bar detailing was sought by analyzing the results of the survey.