• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.1
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• pp.1-12
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• 2016

When utilizing a Tunnel Boring Machine (TBM) for tunnelling work, unexpected ground conditions can be encountered that are not predicted in the design stage. These include fractured zones or mixed ground conditions that are likely to reduce the stability of TBM excavation, and result in considerable economic losses such as construction delays or increases in costs. Minimizing these potential risks during tunnel construction is therefore a crucial issue in any mechanized tunneling project. This paper proposed the potential risk events that may occur due to risky ground conditions. A resistivity survey is utilized to predict the risky ground conditions ahead of the tunnel face during construction. The potential risk events are then evaluated based on their occurrence probability and impact. A TBM risk management system that can suggest proper solution methods (measures) for potential risk events is also developed. Multi-Criterion Decision Making (MCDM) is utilized to determine the optimal solution method (optimal measure) to handle risk events. Lastly, an actual construction site, at which there was a risk event during Earth Pressure-Balance (EPB) Shield TBM construction, is analyzed to verify the efficacy of the proposed system.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.35-43
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• 2013

Nowadays the widely used media in architecture include visualizations, animations and three-dimensional models. 3D digital methods using active CAM(Computer Aided Manufacturing) and CNC(Computerized Numerical Control) imaging have been developed for accurate shape and 3D measurements in freeform buildings. In contrast to a conventional building using auto CAD system and others, the proposed digital optimization method is based on a combination of 3D numerical data and parametric 3D model for design and construction. The objective of this paper is therefore to present digital optimization process for constructability of freeform building. The method can be useful in the effective implementation of an error-proofing process of freeform building during design and construction phase. 3D digital coordinate data can be used effectively to identify correct size of structural and finish members and installation location of each members in construction field. In addition, architects, engineers and contractors can evaluate design, materials, constructability and identify error-proofing opportunities. Other project participants can also include representatives from all levels of management, departments as well as workers and key subcontractors' personnel, if necessary. The 3D digital optimization process is therefore appropriate to serious variations in freeform shape. For future study, the developed digital optimization method is necessary to be carried out to verify the robustness and accuracy for constructability in construction field.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.111-120
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• 2011

High-rise buildings have recently increased over the residential, commercial and office facilities, thus an understanding of construction cost for high-rise building projects has been a fundamental issue due to enormous construction cost as well as unpredictable market conditions and fluctuations in the rate of inflation by long-term construction periods of high-rise projects. Especially, recent violent fluctuations of construction material prices add to problems in construction cost forecasting. This research, therefore, develops a time-series model with the Box-Jenkins methodologies and material prices time-series data in Korea in order to forecast future trends of unit prices of required materials. BIM (Building Information Modeling) approaches are also used to analyze injection time of construction resources and to conduct quantity takeoff so that total material price can be forecasted. Comparative analysis of Predictability of tentative ARIMA (Autoregressive Integrated Moving Average) models was conducted to determine optimal time-series model for forecasting future price trends. Proposed BIM based time series forecasting model can help to deal with sudden changes in economic conditions by estimating future material prices.

• Korean Journal of Construction Engineering and Management
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• v.20 no.4
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• pp.56-68
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• 2019

An optimal selection of form-work is very important in the construction project in terms of construction cost and duration management. Also, it substantially affects the quality of the structure and the finishing work. However, in South Korea, the decision making on the selection of form-work has been based on the experience and intuition of construction practitioners not on the objective data or rational decision-making system. In order to solve the problem, several types of research on the selection of form-work has been processed. However, they did not consider the construction site condition, which is one of the most important factors for the selection of form-work. Thus, the objective of this study is developing the objective decision supporting system considering the site condition. This study provides the quantitative decision support model for optimal form-work based on construction site type. It is expected that the decision support model will help the practitioners decide optimal form-work based on the objective data. It will ameliorate the existing decision making process using experience and intuition. In addition, because the model considers site-conditions, it will provide more accurate and appropriate decision on the selection of an optimal form-work.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.25-37
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• 2019

The conventional representative underground cavity restoration methods, which are mainly open-cut methods, require high cost and long period of time for the restoration. Therefore, various trenchless restoration methods have been proposed to improve these disadvantages. The underground cavity restoration method using the expansive material proposed in this paper is one of the trenchless methods. This method fills the underground cavity with high quality backfill soils through the small hole(s) at asphalt layer and compacts backfill soils by insertion of the expansive material within the cavity. In this study, the restoration method using expansive material was constructed in acrylic chamber. The restoration efficiency of the method was analyzed by the fill ratio and degree of relative compaction according to the location and number of bore holes. As a result of the experiment, the restoration efficiency and the optimum construction location were found to be irrelevant.

• Korean Journal of Construction Engineering and Management
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• v.1 no.3 s.3
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• pp.101-107
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• 2000

On 1 July, 2000, the Ministry of Construction and Transportation announced the Earned Value Management System(EVMS) will be applied in public sector soon. However the arguments over the EVMS applied to our unique construction environment still exist and create strong concerns and worries among some experts it would be another mistakes proposed by the government. We do know the EVMS comes from C/SCSC which was first released by the United States Department of Defense in December 1967, and proved very powerful and efficient project management tool from a lot of practices. Although it is an excellent tool, we can not ignore our many experienced failures appling foreign system due to the differences of construction culture and law between the Korean and US construction industries. The purpose of the EVMS's success in Korea, therefore, this paper tests and proves the EVMS's adaptability and credibility to our construction environment by EAC model, that is one of the most important functions in the EVMS, using very scare EV data of the Korean construction projects.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.51-61
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• 2006

Interchanges are passages for vehicle and pedestrians and a gateway to nearby facilities, and a place to stay of vehicle and Pedestrians. Interchange traffic must be able to navigate well for safety and convenience. Traffic safety and efficiency are influenced by the interchange. In this study, relative delays of vehicles are compared by changing traffic interchanges. the volume of traffic, the number of lanes, the rate of left turns vehicle on the interchanges of urban arterial roads. The object of this study is to compare Grade crossing interchange, Diamond interchange. Roundabout interchange. SPUI(Single Point Urban Interchange), Echelon interchange). Echelon interchange. By VISSIM Simulation, this study drew the relative delay value of every scenario and compared the delay value of each vehicle considering construction expenses. Through this comparison study, ideal interchange is dependent on the volume of traffic, the number of lanes, and the rate of left turns.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6932-6942
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• 2014

The expressway is a key area of road networks for national industry, economics and social development. In addition, the number of lines are increasing continuously. Recently, road management policy have shown a paradigm shift to safe road, low-carbon and green etc. Nevertheless, the road condition has deteriorated dramatically by fatigue cracking, thermal cracking and weather impact. On the other hand, the budgets for highway maintenance have shrunk dramatically. In this study, an effective pavement management and maintenance process was developed to extend the pavement serviceability and pavement life to overcome the rack of budgets.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.114-120
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• 2018

Recently, the plate girder bridge is offen designed a temporary bridge for underground roadway construction have not interrupt railroad operation. The integral support plate girder bridge which have longitudinal girder and cross-girder is improved workability and reduction cost and of construction time. The cross beam of the integral support plate girder bridge has a normal box shape to distribute load on the main girde to end both side girder. In this study, On the change to the web distance of the cross box shows characteristics of related to the stresses and displacements on the flange and web plate. Afterward, the various analysis contributed to the safety improvement of crossbeam of the integral support crossbeam plate girder bridge.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.26-32
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• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power Therefore, there has been and still is a growing concern(safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline, especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion limitation of safety voltage and analysis of induction voltage.