• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.113-114
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• 2016

This paper proposes a technical requirements analysis of implementation of multi-trade prefabrication. Recently, there has been a rise in the use of prefabrication to minimize on-site work for time reduction to increase productivity. Prefabrication technique is evolved into multi-trade prefabrication combining other trades from single-trade prefabrication. For implementation of new technique, not only itself but complementary techniques have to be prepared. In this paper, MEP corridor rack, a major item of multi-trade prefabrication, was implemented in the test bed and its process was analyzed to find out technical requirements. As a result, comparatively high level of IT technique was required for efficient use of multi-trade prefabrication in design, lifting and construction phase. In design phase, component level of BIM library was needed for manufacturing; and in lifting phase, BIM-based site logistics process was required. Also in construction phase, laser scanning was implemented for gathering shape and geometry of the wall and slab that were attached to multi-trade prefabrication module.

• Journal of Construction Engineering and Project Management
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• v.4 no.4
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• pp.33-40
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• 2014

Maximizing the profitability and minimizing the duration of construction projects in extreme weather regions is a challenging objective that is essential for project success. An optimization model is presented herein for the time-profit trade-off analysis of construction projects under extreme weather conditions. The model generates optimal/near optimal schedules that maximize profit and minimize the duration of construction projects in extreme weather regions. The computations in the model are organized into: (1) a scheduling module that develops practical schedules for construction projects, (2) a profit module that computes project costs (direct, indirect, and total) and project profit, and (3) a multi-objective module that determines optimal/near optimal trade-offs between project duration and profit. One example is used to show the impact of extreme weather on construction time and profit. Another example is used to show the model's ability to generate optimal trade-offs between the time and profit of construction projects under extreme weather conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.76-77
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• 2015

In construction industry, management of construction factors such as cost, schedule, quality and safety is the most important key for delivering successful projects. According to the Smart Market Report, a magazine specialized in construction industry, recently said 'Off-site Prefabrication' is a significant trend related with construction productivity in global construction industry. It is a kind of practice shift from On-site to Off-site. A lot of general contractors in oversea have been using 'Multi-trade MEP Ceiling Rack Prefabrication' method for getting benefits such as decreased cost & schedule and increased labor productivity. Thus, in this paper, critical management factors at each phase from design to installation was derived by researching case studies. Forwardly, it can be a basic guideline for applying Multi-trade MEP Ceiling Rack Prefabrication in Korea construction industry.

• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.91-98
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• 2008

It is time-consuming and difficulty to solve the time-cost trade-off problems, as there are trade-offs between time and cost to complete the activities in construction projects and this problems do not have unique solutions. Typically, heuristic methods, mathematical models and GA models has been used to solve this problems. As heuristic methods and mathematical models are have weakness in solving the time-cost trade-off problems, GA based model has been studied widely in recent. This paper suggests the time-cost trade-off optimization algorithm using particle swarm optimization. The traditional particle swarm optimization model is modified to generate optimal tradeoffs among construction time and cost efficiently. An application example is analyzed to illustrate the use of the suggested algorithm and demonstrate its capabilities in generating optimal tradeoffs among construction time and cost. Future applications of the model are suggested in the conclusion.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.84-85
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• 2013

Integrating multi-trade works system helps to reduce to minimize the conflict of subcontract business and improve communication to increase productivity of construction. However it takes such a big risk if subcontract of integrating multi-trade works went bankrupt during the project so some of construction companies executed to only small project and it's not sufficient to adopt overall project. This paper suggested the improvement scheme of work classification integrating multi-trade works, which takes a consideration into work zoning in order to apply current work situation.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.712-713
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• 2015

In recent years, the bid-rigging in public construction markets has been treated as a critical issue in Fair Trade Commission. The investigation revealed that the collusion was implemented extensively in every area from the material supply to the construction service of general contractors. This study reviewed the causes of the bid-rigging in public construction projects, and proposed the improvement plan to eradicate bad practices. Firstly, the causes and purposes of bid-rigging were categorized into two types of internal factors from construction companies and external environment factors influencing business activities. Secondly, the system development method was explained to detect the signs of bid-rigging based on the technical proposal documents in open tender. The detection systems of repetitive public owner also provide the function of sharing data on the companies and cases to violate the fair trade regulation. In addition, the problems and improvement direction of public procurement policies were discussed.

• Safety and Health at Work
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• v.6 no.2
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• pp.151-155
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• 2015

The study was designed to identify any trends of injury type as it relates to the age and trade of construction workers. The participants for this study included any individual who, while working on a heavy and highway construction project in the Midwestern United States, sustained an injury during the specified time frame of when the data were collected. During this period, 143 injury reports were collected. The four trade/occupation groups with the highest injury rates were laborers, carpenters, iron workers, and operators. Data pertaining to injuries sustained by body part in each age group showed that younger workers generally suffered from finger/hand/wrist injuries due to cuts/lacerations and contusion, whereas older workers had increased sprains/strains injuries to the ankle/foot/toes, knees/lower legs, and multiple body parts caused by falls from a higher level or overexertion. Understanding these trade-related tasks can help present a more accurate depiction of the incident and identify trends and intervention methods to meet the needs of the aging workforce in the industry.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.385-388
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• 2002

The construction industry has complicated production processes with diverse disciplines and subcontractors, which is the major cause of lowered productivity. To solve this problem, multi-trade subcontract system is recently suggested. Some general construction companies have applied this method to some sections of work process. However, this is in the early stage of application. The purpose of this study is to define an integrated contract package for improving both contractor and subcontractor efficiency. First, this study recognizes construction company to need of multi-trade subcontract system. Finally, it suggests feasible activities which can be useful for a construction company to apply to this subcontract system.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.16-27
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• 2022

This study analyzed both the legal system regarding fair trade and the types of unfair trade in the construction industry. Then, it derived the factors with which to evaluate the level of fairness. These factors were classified by each type of participant in the construction industry, such as general contractors and subcontractors, and each construction stage, such as bidding, contracting, and construction. The perceived fairness level of factors was analyzed using a survey of 238 employees of general contractors and subcontractors. Next, the study developed a fairness index for the construction industry. The index showed that subcontractors perceived the level of fairness more negatively than general contractors, but both perceived the construction stage of the industry as having the lowest level of fairness. General contractors perceived the bidding and contracting stages as having the highest fairness levels, and subcontractors perceived the contracting stage as having the highest level of fairness. The developed fairness index identified the evaluation factors that need improvement and the fairness level perceived by each type of participant at each stage of construction. The results of this study can contribute to establishing measures that improve the level of fairness in the construction industry.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.308-316
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• 2023

Objectives: The aim of this study is to measure and assess the occupational noise exposure levels among construction workers at apartment building construction sites in South Korea. Methods: Noise exposure assessments were conducted for 139 construction workers across 10 different trades at 53 apartment building construction sites in the northern part of Gyeonggi-do. Assessments were carried out using a noise dosimeter set with a 90 dB criterion, an 80 dB threshold, and a 5 dB exchange rate over a period of more than 6 hours(L_MOEL) Results: The mean L_MOEL (equivalent continuous noise level over 8 hours) for the 139 dosimeter samples was 87.8 ± 4.3 dBA. The mean noise exposure level for each construction trade, referred to as the trade mean, was also calculated. Significant differences in noise exposure levels were observed between construction trades (ANOVA, p < 0.001). The highest L_MOEL values were recorded for concrete chippers (93.2 ± 2.6 dBA), followed by ironworkers (88.4 ± 0.7 dBA), concrete finishers (88.3 ± 2.7 dBA), masonry workers (87.7 ± 1.9 dBA), pile driver operators (85.6 ± 1.7 dBA), concrete carpenters (84.9 ± 2.4 dBA), interior carpenters (83.5 ± 2.1 dBA), and other groups (81.4 ± 2.2 dBA). Conclusions: The findings suggest that nearly all construction workers in this study are at risk of Noise-Induced Hearing Loss (NIHL). Moreover, the study establishes that construction trades can serve as a useful metric for assessing noise exposure levels at apartment construction sites.