• Korean Journal of Construction Engineering and Management
• /
• v.19 no.6
• /
• pp.3-13
• /
• 2018

The formwork cost amounts for a significant proportion of project construction costs. It costs 10-15% of the total construction cost and 30-40% of the frame structure construction cost. In addition, the formwork collapse accidents are frequently causing deaths in the construction industry, and thus, is known to be of relatively high degree of risk. As so, the accuracy of structural calculation and quantity take-off when planning the formwork in a construction project are a very important matter. Accordingly, this study develops a BIM based formwork design prototype, that enables the construction manager to optimize the design through applying the proposed new IFC entities associated with the formwork design. The approach proposed in this study is expected to support the construction manager with accurate quantity calculation and rapid planning and construction. Since this study considered specific small-scale buildings using Euro-form and show the possibility of utilizing BIM entities in the formwork design process, further research is recommended towards the limitations in applying the system to other types of formworks.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.6
• /
• pp.587-594
• /
• 2016

This study aims to analyze the benefit-cost of the cleaning device for photovoltaic power generation systems in buildings in order to check its economic feasibility. A product, which has similar characteristics to the ultrasound-based cleaning device and is widely used in South Korea, was selected to compare with the benefit-cost value of the ultrasound-based cleaning device in this study. In order to quantitatively and qualitatively analyze benefit and cost aspects of the two products, categories and evaluation factors of each aspect as well as evaluation criteria were identified. Based on the identified evaluation factors and criteria, this study conducted face-to-face interviews with 15 experts to measure weights of benefit and cost aspects of the products. As the results, the total benefit weight of the ultrasound-based cleaning device was larger than its total cost weight since the benefit-cost value was greater than 1, which was 1.6 times of that of to compared product. Therefore, from the economic perspective, it is worth to develop the cleaning device for photovoltaic power generation systems applying ultrasound technology.

• The Journal of Engineering Geology
• /
• v.26 no.4
• /
• pp.485-495
• /
• 2016

To reinforce and improve the soft ground under a breakwater while using materials efficiently, the replacement ratio and leaving periods of surcharge load are optimized probabilistically. The results of Bayesian updating of the random variables using prior information decrease uncertainty by up to 39.8%, and using prior information with more samples results in a sharp decrease in uncertainty. Replacement ratios of 15%-40% are analyzed using First Order Reliability Method and Monte Carlo simulation to optimize the replacement ratio. The results show that replacement ratios of 20% and 25% are acceptable at the column jet grouting area and the granular compaction pile area, respectively. Life cycle costs are also compared to optimize the replacement ratios within allowable ranges. The results show that a range of 20%-30% is the most economical during the total life cycle. This means that initial construction cost, maintenance cost and failure loss cost are minimized during total life cycle. Probabilistic analysis for leaving periods of shows that three months acceptable. Design optimization with respect to life cycle cost is important to minimize maintenance costs and retain the performance of the structures for the required period. Therefore, more case studies that consider the maintenance costs of soil structures are necessary to establish relevant design codes.

• Journal of Construction Engineering and Project Management
• /
• v.3 no.3
• /
• pp.35-41
• /
• 2013

All infrastructure projects are said to be inter-dependent, uncertain and labour-intensive in nature. There is no exception for building services sub sector. For a real time project such as 'The construction, extension and refurbishment of Employees' State Insurance Corporation (ESIC) Hospital at Tirupathy, India with total area of 45,000 square feet at an estimated cost of 1100 million rupees, a generic process model is developed to simulate the effect of set of identified variables on construction project. The 'Stocks and Flows' of dynamic model affords relevant insights to project managers, who apply this knowledge when designing better performance through more appropriate project planning. It is concluded from the model-based approach that building services works can be improved through specific better focussed managerial efforts, such as an increasing coordination effectiveness at the planning stage, clarifying prerequisite conditions prior to installations. Otherwise, pending works arising from work clashes can lead to knock-on effects resulting in productivity constraints and pressures, as well as more rework and demolition. Current study reveals that the model enables deep insight into various interdependent processes, their by improving construction performance levels, by addressing the dynamics of design errors and defective works, and recovering delayed schedule.

• KIEAE Journal
• /
• v.8 no.2
• /
• pp.87-92
• /
• 2008

Underground building constructions are recently more important because the ratio of underground area is increasing in the huge and high-rise building construction projects. For reducing the total building construction periods, it is required to reduce not only the over-ground structural work periods but also the underground structural work periods. Therefore, this study is proposed the non-supporting system forms for single face walls in underground building construction by one of the methods for reducing the underground structural work periods and investigated the applicability of the non-supporting system forms by analyzing the case-study in civil construction project. In regard of construction duration, the results of analyzing the case-study showed that the non-supporting system forms are better than the euro forms with soldier system for single face walls in underground building construction. In addition, it is showed that the cost of these two forms is similar and usage the working space and safety in non-supporting system forms are better that those of the euro forms with soldier system, too.

• International Journal of Railway
• /
• v.9 no.1
• /
• pp.21-26
• /
• 2016

When excavation under existing structure is planned for a new construction project, the underpinning method is one of the most applicable construction methods. This study introduces a new modified underpinning method which is applied to construct a new subway line in Seoul Metropolitan. The new subway line was designed to pass underneath the existing subway line. Existing subway line carries about 2 million passengers daily, which is 33% of total passengers using subway in Seoul, and is the only circulation line in Seoul. Subway trains are passing 540 times through this section in a day. By applying a new underpinning method, the subway box structure of line is exposed 54m in the air supported by bearing piles. The proposed method was carefully monitored using heavy instrumentation system during construction. This study proposed and verified the application of the modified underpinning method, which can reduce construction period by 1.5 times and the construction cost by 1.2 times comparing with conventional method. The importance of considering construction sequence is investigated and verified by analyzed data non-considering construction sequence. The unexpected heaving which can bring up a dangerous situation for train running stability were measured, so this study shows that the upward movement has to be analyzed in designing process. As the use of underground space increases, the proposed method can be a good example of underground development.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.11a
• /
• pp.195-196
• /
• 2017

The number of human accidents in the construction industry is increasing every year, and it constitute the highest percentage among industry. This means that activities performed to prevent safety accidents in the country are not efficient to reduce the rate of accidents in the construction industry. In order to solve this issue, research has been conducted from various perspectives. But, research regarding to quantification model of human accidents is insufficient. the objective of this study is to conduct a basic study on quantification model development of human accidents. To achieve the objective, first, Cause of accident is defined the through literature review. Second, a basic statistic analysis is conducted to determine the characteristics of the accident causes. Third, the analysis is conducted after dividing into four categories : accumulate rate, season, total construction cost, and location. In the future, this study can be used as a reference for developing the safety management checklist for safety management in construction site and development of prediction models of human accident.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.5
• /
• pp.468-481
• /
• 2011

This research presents a strategy and information system to manage the logistics of delivery ready mixed concrete (RMC) under the integrated environment of PMIS+RFID. PMIS is system tool and technique used in construction sectors to delivery information. Information that can be extracted electronically in real time is more valuable than data gathered and maintained manually. RFID technology can help to improve data accuracy through supply chains and by identifying products and objects at specific points through automatic identification. The objectives of these two implementations can be able to improve the efficiency of logistics management for RMC truck process, and to verify the technical and practical feasibility of PMIS+RFID application in construction industry. This may be realistic given the dynamics of daily activities on construction sites. This research is focused on examples on real world case study, applications and research theme related and connected to PMIS+RFID technology. It demonstrated that PMIS+RFID technology has been automatically implemented and has shown process information about the RMC truck and the overall status information about it, both quickly and accurately. As a result, the construction site where needs 300 $m^3$ pouring (50 RMC trucks) per day can be reduced total 250 minutes. Moreover, this time saving is related to the labour cost saving. From the case studies, RFID+PMIS system was proven in terms of effectiveness rather than current method.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.2
• /
• pp.173-178
• /
• 2018

This study organizes scenarios on the power supply and demand plans considering the uncertainties and the portion of distributed energy resources. In analysing the scenarios, it estimates total electricity supply cost in the social aspect, natural gas demand and air pollutants emission including carbon dioxide. Also the analysis is performed to estimate the marginal cost of carbon dioxide reduction for the fuel switching from coal to liquified natural gas. In result, the social cost could be decreased by replacing some portion of renewable energy by LNG-based combined heat and power and delaying the construction of large base-load generators such as coal and nuclear plants. The marginal carbon dioxide reduction cost by fuel switching is in plausible range for fuel switching to be an option for carbon dioxide emission reduction when the social cost is considered.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.128-132
• /
• 2003

This paper deals with the development of IGBT stacks for cost reduction. One stack is consist of 4 IGBTS in parallel. In the high- and mid-power converters, IGBT stacks are more suitable than single IGBTS in the aspects of total cost of semiconductor devices, time for purchasing, maintenance, radiation of heat, size of surge absorber and harmonic filter, frequency characteristics, and etc.. Problems accompanied by parallel construction are studied and solved. Economical efficiency is discussed and field tests with 100kVA UPS are tarried out to verify the validity of the developed IGBT stacks.