• Korean Journal of Construction Engineering and Management
• /
• v.16 no.4
• /
• pp.139-145
• /
• 2015

Modular construction is combined with manufacturing production process and conventional construction industry technique. Considering characteristic of modular construction production process, manufacturing facilities require indirect costs for utilities, equipment, and overall maintenance, which can affect modular units pricing. However, current modular construction cost classification is inadvertent to reflect the manufacturing overhead costs, because it is generally added as a percentage to sum of labor, material and equipment as it called in single cost pool used. This process is easy to estimate the total construction cost at the project starting points, but it brings on misunderstanding of project profit estimations by "cross subsidization phenomenon". To prevent this situation, in this research aims to provide modular construction overhead cost handling process at the detailed indirect cost calculation for manufacturing stage using Activity-Based Costing as one of the powerful method for overhead costs estimation and allocation. Using this research results, modular construction cost estimators have more detailed cost information of modular units and prevent to misallocate indirect costs. Also, it can be utilized to aid the understanding of the company's profit structure.

• Korean Journal of Construction Engineering and Management
• /
• v.16 no.5
• /
• pp.54-64
• /
• 2015

The modular construction has several advantages such as high quality of product, safe work condition and short construction duration. The manufacturing planning of modular construction should consider time frame of manufacturing, transport and erection process with limited resources (e.g., modular units, transporter and workers). The manufacturing planning of multi modular construction project manages the modular construction's characteristics and diversity of projects, as a type of modular unit, modular unit quantities, and date for delivery. However, current modular manufacturing planning techniques are weak in dealing with resource interactions and each project requirement in multi modular construction project environments. Inefficient allocation of resources during multi modular construction project may cause delays and cost overruns to construction operation. In this circumstance, this research suggest a manufacturing planning model for schedule optimization of multi project of modular construction, using genetic algorithm as one of the powerful method for schedule optimization with multiple constrained resources. Comparing to the result of the existed schedule of case study, setting optimized scheduling for multi project decrease the total factory producing schedule. By using proposed optimization tool, efficient allocation of resource and saving project time is expected.

• Korean Journal of Construction Engineering and Management
• /
• v.13 no.5
• /
• pp.103-112
• /
• 2012

Republic of Korea is recently becoming an advanced country with increasing standard of living. This is causing a lack of employment in the construction industry because of high labor costs and it is resulting rapid increase in foreign labors. Modular Method of Construction can be defined as 50%~90% of the entire process is completed in factory, and transferred to construction field to install. The main purpose of this process is to minimize the entire process that possibly can be done at construction field in order to maximize the quality. The current local usage of Modular Method of Construction started at Shin Ki Elementary School during 2003 and it is widely used for military facilities. It should be used more because it has strengths of spending short time period to complete and low production costs. It can make a change if Modular Method of Construction is applied. Toyota is currently producing vehicle with conveyor system and if Modular Method of Construction is applied, then it is possible to reduce the waste of labor, and automatic production time. Expansion of the modular Market can be expected by applying this method because it will improve producing costs, high quality, and enforced process. This research tried to solve the problem of factory's manufacturing production by applying local Modular Method of Construction to provide suggestions and analyze the profitability with applied conveyor system. It is depending on produced model, but this research's model will take 20 months including assessment of payback period.

• Korean Journal of Construction Engineering and Management
• /
• v.18 no.6
• /
• pp.98-108
• /
• 2017

Recently, the development of middle and high-rise building technology using modular construction method has emphasized the importance of site construction error management. The modular construction method is very limited to adjust the construction error in the field because of the factory production characteristics. Therefore, in order to prevent the construction error in advance, a management plan reflecting the characteristics of the modular construction method is required, and it is important to make the decision of the construction participant at each stage. This study analyzed the factor of construction error of modular construction and suggested a decision support model for construction error management based on construction process. The result of this study is expected to be a guideline for the modular construction participant to derive the construction error management plan.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.1
• /
• pp.43-53
• /
• 2018

Modular construction can improve construction quality and accuracy through manufacturing process, and it allow massive production and cost savings by repeatedly producing the same unit. In particular, it is possible to reduce the time because the on-site work and the manufacturing process can be carried out at simultaneously. However, according to the modular construction project survey report, there is no significant difference regarding the average construction period between modular construction and conventional construction. This is due to schedule delay problems that occur during construction phase. Therefore, it is necessary to select alternatives to prevent schedule delay during on-site construction progressing. Especially, in case of large-scale modular construction project, on-site module assembly and manufacturing process are performed concurrently. Hence, identification of alternatives should be done at the co-occurrence by taking both manufacturing and on-site work process in to account. In this research, the management factors of large-scale modular construction project were identified through the IDEF0 modeling, and the quantity management model for manufacturing and assembly is developed. This will reduce the schedule delay problem that occurs in the progression on-site work of a large scale modular construction.

• Korean Journal of Construction Engineering and Management
• /
• v.15 no.1
• /
• pp.11-19
• /
• 2014

The Construction industry is a labor-intensive industry that its labor cost takes up about 30~40% out of the whole construction cost. However, due to a stereotype that on-site work is a 3D job there is a shortage of the labor forces. Modular construction method is to produce modular units in the plant so that workers could work stably. Also, after delivering the module from plant to the site, there will be only installment to be required that shortens construction duration. Even though the modular market is currently expanding based on military facilities in Korea, its best strengths are not demonstrated well which are shortened construction period and low cost. It also causes labor problem of production due to minimum utilization of the modular construction method. Multi-skilled labor means a technician that is able to perform more than two kinds of work with more than two techniques. Multi-skilled labor can proceed smoothly by figuring out the connectivity between the precedent and following operations. Therefore, this research is to apply the concept of Multi-skilled labors, suggest solutions and allocate manpowers efficiently. As a result, it helps to decrease idle manpowers during the operation and the total labor forces can be saved. Low cost is the original strength of the modular which can stand out so the modular market is expected to expand.

• Korean Journal of Construction Engineering and Management
• /
• v.15 no.5
• /
• pp.138-146
• /
• 2014

Modular construction is one of the arising issues in the Korean construction industry due to shorter construction period and higher productivity on site. It is also expected that modular construction market would expand rapidly because of increasing demand of small houses by nuclear families and eco-friendly construction. However modular construction cases have been limited in Korea because of little demand in the market and the construction prices are even higher that the regular reinforced concrete methods. Even worse, because there is no standard bill of services exists in the industry, it may lead to the risk of construction expenses. So, the purpose of this study is focused on the development of bill of services which reflects characteristics and process of modular construction. In order to do this, the concepts and process of modular construction, WBS and CBS are analyzed. Analyses of the case studies and experts interview were executed so that proper principles for organizing bill of service of modular construction is established. Finally according to the 3 steps of modular construction, factory manufacturing, on-site modular construction and on-site general construction, the standard bill of services were suggested with the related coding system.

• Korean Journal of Construction Engineering and Management
• /
• v.22 no.1
• /
• pp.36-46
• /
• 2021

With an increasing trend toward high-rise modular construction, the simultaneous use of tower cranes at a modular construction site has recently been observed. Tower crane layout planning (TCLP) has a significant effect on cost, duration, safety and productivity of a project. In a modular construction project, particularly, poor decision about the layout of tower cranes is likely to have negative effects like additional employment of cranes and redesign, which will lead to additional costs and possible delays. It is, therefore, crucial to conduct thorough inspection of field conditions, lifting materials, tower crane capacity to make decisions on the layout of tower cranes. However, several challenges exist in planning for a multi-crane construction site in terms of safety and collaboration, which makes planning with experience and intuition complicated. This paper suggests a multi-objective optimization model for selection of the number of tower cranes, their models and locations, which minimizes cost and conflict. The proposed model contributes to the body of knowledge by showing the feasibility of using multi-objective optimization for TCLP decision-making process with consideration of trade-offs between cost and conflict.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.182-189
• /
• 2019

3D printing technology is changing the paradigm of consumer-oriented design in supplier-oriented mass production. 3D printing technology in construction is expected to be able to replace existing wet methods along with modular construction. Recently, a number of cases of building construction using 3D printing using mortar-based materials have been announced in many regions, including North America, Europe, and Asia. In this study, we developed a design support tool with a slicing function to output 3D modeling for architecture for a 3D printing machine. We analyzed the process and the function of slicing programs that are commercially available. Seven slicing functions required for the architectural field were derived by analyzing cases, expert reviews, and related literature. The derived functions were extended from the slicing functions to develop the design support tools. Detailed algorithms and processes need to be developed for future derived functions.