• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.885-888
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• 2008

In recent years, the terminology "High-Performance Concrete(HPC)" has been introduced into the construction industry. Most high-performance concretes have a high cementitious content and a low water-cementitious material ratio. The proportions of the individual constituents vary depending on local preferences and local materials. Therefore, many trial batches are usually necessary before a successful mix is developed. The objective of this experiments is to investigate the fundamental properties of high performance concrete based binary cimentitious materials such as ordinary portland cement and ground granulated blast furnace slag. The results from the study will be utilized as the basic data and guideline in making standard mixproportions and the manufacture, construction work and quality control of HPC

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.84-91
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• 2008

"Eco-friendly construction" is an emerging issue in the building industry. Main purpose of the eco-friendly construction is to sustain the health and environment of building residents and to minimize the harmful effect on their environment. Apartment residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Environmental performance is to meet through using the highest grade eco-friendly materials. However, generally eco-friendly materials are more expensive than normal materials, Therefore, using eco-friendly materials at public housing project is limited to economical aspect. The purpose of this paper is development of eco-friendly material selection model considered cost efficiency. The selection of Eco-friendly finishing materials and their methods are constructed to consider environmental performance level and cost index compositively. Development of eco-friendly material selection method is economic and reasonable one when public housing is constructed.

• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.365-372
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• 2014

Technologies for rapid concrete curing using elevated temperature are important for saving cost and time when constricting concrete structures. Recently, a microwave heating form was developed. In this study the early strength of concrete cured by the developed form was experimentally investigated. Large scale mock up tests were conducted six times, and the results were analyzed based on the maturity theory. Logarithmic correlation curves were generated based on the measured strength and estimated maturity. It was confirmed that the strength development of the concrete cured by microwave heating form can be estimated by the equivalent age theory usually applied to steam-curing technology. By using the microwave heating form, one day at most is enough to get the required strength for the safe removal of forms, even in cold weather.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1091-1104
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• 2018

Wear prediction of TBM disc cutters is a very important issue during design as well as construction stages for hard rock TBMs as the cutter head intervention is directly related to the time and cost of tunneling. For that, some methods such as NTNU, CSM and Gehring models were used to predict disc cutter wear and intervention interval. There are however some problems to be addressed in these models in terms of accuracy and time for testing, so that a NAT (New Abrasion Tester) model has been developed in order to achieve simplicity and reliability together at the same time (Farrokh and Kim, 2018). On the basis, the proposed NAT model has been applied to ${\bigcirc}{\bigcirc}$ project in Korea. A comparative study was performed to compare with the conventional methods and as a result the NAT model showed a very good agreement with actual cutter life. The NAT model will be further applied to other projects to establish credibility.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.735-747
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• 2019

Due to the lack of ground space by urbanization, the demand of utility tunnels for laying social facilities is increasing. During the construction of a utility tunnel in downtown area using a shield TBM, various problems may occur when difficult ground is encountered such as mixed ground and cobbly ground. Thus, in this study, using MIDAS GTS NX (Ver. 280), a numerical analysis was performed on characteristics of difficult ground, reinforced area, depth of cover and groundwater level to analyze the optimal ground reinforced area according to combination of parameters. As a result, it was difficult to secure stability in unconstrained excavation cases on both the mixed ground and the cobbly ground. However, when ground reinforcement grouting as much as 2.0D is applied, convergence occurred within the allowable limit, except for mixed ground with a depth of cover 30 m. In addition, excessive leakage occurred during excavation of both the mixed ground and the cobbly layers. It was able to secure stability after applying waterproof grouting.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.135-145
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• 2009

The main goal of construction projects from the past has been enhancing efficiency by reducing cost and time. but, seeing the current condition of safety management of many construction companies nowadays, it is true that not much attention has been paid to safety management for a long time. However, there are paradigm shift from the cost and term of works to safety management in the construction industry, from this circumstance the safety management is evaluated more importantly. Though less accident happens compared to past, the accidents are getting greater because construction projects nowadays are bigger and more complex and monetary loss from the accidents are increasing. Also, the severity is getting greater and even fatal. For this reason, more improved safety management is very necessary. Therefore, we are to propose more efficient system for safety management in this thesis. Technical parts for developing system include many technique such as Real Time Locating system, and other techniques like Monitoring module based on BIM, Data Mart, Alarm are also applied together. Through this system, in the construction site, safety management is performed more effectively and widely because the system can manage the human resource and fluid situation. Also, safety manager can conduct more systematically and advanced safety management through human resource dominated safety management.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.39-48
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• 2016

In this study, it can be shortened tunnel construction work period by introducing a single-shell tunnel does not placing the secondary concrete lining, a global research trend, reduction of the cost of the lining placement and number of benefits that can ensure the safety of long-term tunnel with a single shell it was to study the tunnel method. First, we analyze the design and construction practices relating to delete lining of the domestic design and construction practices and a comprehensive analysis of the stability study found a rock in good condition interval (1~3 grades), we propose that the lining uninstalled. In the case of domestic changes on the ground floor is very heavy underfoot conditions many so tunneling method by single shell as ground conditions are good and one preferred the water points that apply in less soil, the soil health and poor sections (4~5 grades) reflecting with respect to the concrete lining that is expected reasonable.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.261-275
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• 2020

When excavating a small cross-section tunnel in a fault fracture zone using the shield TBM method, there is a high possibility of excessive convergence and collapse. Appropriate ground reinforcement is required to minimize construction cost loss and trouble due to a fault fracture zone. In this study, the optimal reinforcement area was suggested and the surrounding ground behavior was investigated through numerical analysis using MIDAS GTS NX (Ver. 280). For the parameters, the width of the fault fracture zone, the existence of fault gouge, and the groundwater level and depth of cover were applied. As a result, when there is not fault gouge, the convergence and ground settlement are satisfied the standard when applying ground reinforcement by up to 0.5D. And, due to the high permeability coefficient, it is judged that it is necessary to apply 0.5D reinforcement. There is a fault gouge, it was possible to secure stability when applying ground reinforcement between the entire fault fracture zone from the top of the tunnel to 0.5D. And, because the groundwater discharge occurred within the standard value due to the fault gouge, reinforcement was unnecessary.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.22-31
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• 2019

The application of BIM that can manage and integrate information generated during the entire life cycle of buildings in domestic and overseas construction projects is becoming active. When BIM is utilized in the construction phase, it can shorten the construction period, reduce the occurrence of reworks and improve collaboration capability. However, there are limitations in applying BIM to the construction phase due to the insufficient definition level of domestic BIM guidelines and inadequate design standards. In this regard, this study developed BIM model requirements checklist for the application of BIM in the construction phase. To develop the checklists, 21 domestic and overseas BIM guidelines, three public construction projects and four private construction projects to which construction BIM was applied, were analyzed. Based on the guidelines and cases, a total of 62 construction BIM model requirements (31 model objects and 31 attribute rules) and proposed construction BIM model requirement checklists by dividing the 61 requirements according to the requirement and purpose for utilization were identified. It is expected that the practical applications of the checklists proposed in this study will improve the level of BIM model in construction phase. In addition, this study has its significance as a basic research that can be used in the development of standardized guidelines for BIM model in construction phase from academic aspects.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.78-90
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• 2013

The purpose of this study was to analyze the types and characteristics of public complaints caused by the landscape architecture projects in the case of apartment complex. Furthermore, its purpose was also to propose as the basis data for the minimization of complaints in the course of future landscape architecture projects. To analyze and categorize the apartment complex civil complaints, we collected basic and case study data from LH Corporation, SH Corporation and GICO from 2009 to 2012. We also categorized 672 landscape complaints to 73 categories and conducted a survey from residents and landscape architecture. This Survey is to use IPA can collect character(public-private), handling of civil affair(easy-hard) and analyze typical characters and difference of civil complaint awareness between landscape architecture and residents. First, we were categorized 73 civil complaints by type in 5 categories such as park, green space and street trees, pedestrian road, facilities, and others. Second, the most common landscape complaints appear in green spaces, street trees, facilities, pedestrian roads and park orders. Third, results of the analysis conducted for each item which are publicity and measures the ease. 'Facilities', 'landscape and greenery', 'pedestrian road' and others were commonly appears from residents and professional awareness of the complaints. However, complaints of park appear different awareness between landscape architecture and residents. Fourth, 35 from 73 civil complaints(47.9%) are having high publicity and easy to measure, 25 civil complaints(34.2%) has analyzed to individual and difficult to measure so about the these complaints need to check from the design step so that it is necessary to minimize the problem of additional expense by civil complaints burden and decrease the confidence of residence problem were considered.