• Economic and Environmental Geology
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• v.44 no.6
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• pp.525-532
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• 2011

In this study, the usefulness of underground dam as a means for the sustainable development of groundwater, and its performance in the management of groundwater resources were analyzed. The fully integrated SWAT-MODFLOW was applied to the Ssangcheon watershed in Korea to evaluate the effectiveness of groundwater dam construction. After construction, the groundwater level raised in the upstream area of groundwater dam while lowered in the downstream area. Also, it is shown that the exchange rate of river-aquifer interactions increased in the upper area of the dam. Since the storage capacity of the aquifer largely increased in the upper area of the dam, the exploitable groundwater could be greatly increased as much. This study demonstrated that a groundwater dam was a very useful measure to increase the available storativity of groundwater aquifers. It also represented that the combined analysis using SWAT-MODFLOW was helpful for the design and opeation of groundwater dam in the Ssangcheon watershed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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• pp.95-102
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• 2002

The flexural behavior of the reinforced concrete (RC) structure upgraded by external reinforcements was examined in this study. It is well known that the incorporation of carbon fiber sheet (CFS) with concrete is one of the most effective ways to strengthen the RC structure. Complete bonding is required between CFS and concrete in order to make the RC structure provide its full function until the time the Re structures serve. Many studies have reported that construction deficiencies have caused the debonding of the CFS from concrete before the RC structure with CFS reaches its ultimate capacity. This research took a systematic look at the failure mechanism, macroscopic load-deformation characteristics, the maximum load applied, and maximum bending moment when construction deficiencies exist. The results of the experiment conducted were compared with theoretically derived values. In the future, the results of this investigation will help minimize the factors of construction deficiencies, which may occur when CFS is used to reinforce a RC structure. The experiment was manipulated with steel reinforcement ratio and piles of CFS on a total of 14 beams ($20cm{\times}30cm{\times}240cm$). The results showed that internal moment capacity increased even when construction deficiencies existed. However, RC structures with CFS in the field still contain a considerable level of potential risks.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.11-20
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• 2014

The behaviors and stability of reinforced subgrade with short geogrid were examined and evaluated during construction. First of all, analytical approach for the minimum length of geogrid was performed to guarantee stability during construction loading state. Secondly, the economic aspects for reinforced subgrade were compared with between domestic standards applying with 0.7 H reinforcement length and new way to mix short and long reinforcement. Full scale railroad subgrade was constructed with the size of 5 m high, 6m wide, and 20m long to verify the stability of the subgrade with the length of 0.3 H, 0.35 H, 0.4 H reinforcement. Total 51 sensors were installed to measure settlement, bulging, and the change of stress of the subgrade. It is concluded that the reinforced subgrade with short(0.35H, 35% of height) geogrid had stability within allowable level of deformation and stress increment during construction.

• Wind and Structures
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• v.2 no.1
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• pp.25-40
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• 1999

In this paper, artificial neural networks, a new kind of intelligent method, are employed to model and predict amplitude dependent damping in buildings based on our full-scale measurements of buildings. The modelling method and procedure using neural networks to model the damping are studied. Comparative analysis of different neural network models of damping, which includes multi-layer perception network (MLP), recurrent neural network, and general regression neural network (GRNN), is performed and discussed in detail. The performances of the models are evaluated and discussed by tests and predictions including self-test, "one-lag" prediction and "multi-lag" prediction of the damping values at high amplitude levels. The established models of damping are used to predict the damping in the following three ways : (1) the model is established by part of the data measured from one building and is used to predict the another part of damping values which are always difficult to obtain from field measurements : the values at the high amplitude level. (2) The model is established by the damping data measured from one building and is used to predict the variation curve of damping for another building. And (3) the model is established by the data measured from more than one buildings and is used to predict the variation curve of damping for another building. The prediction results are discussed.

• Journal of Korean Society of Archives and Records Management
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• v.7 no.2
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• pp.113-138
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• 2007

This study was started from a critical mind for the construction records management in South Korea and examined the state of the construction records management system of the Korea Rail Network Authority which is constructing the biggest Express Railway Construction of National Project in Korea. The Methodology of this study is based on the functional requirement of the Records Management International Standard, ISO 15489, which standardized the record management process in the cases of Record Capture, Declaration, Classification, Storage, Access, Tracking and Disposition. In regard to the functional requirements from Capture to Disposition, each level(title) consists of 3 to 4 items, for a total of 22 principles in all. The estimation was created for each of the 22 categories using 4 levels: observance, partial observance, insufficiency and non observance. And pointing out the problem, suggesting the improvements for the Korea Rail Network Authority and structural improvements according to the KS X ISO 15489 principles.

• Korean Journal of Construction Engineering and Management
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• v.20 no.5
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• pp.3-11
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• 2019

This study is designed to examine the stock price of construction firms which are affected by the deregulation of new apartment sales price. As empirical methodology, it uses the traditional event study analysis to test the influence of the deregulation of new apartment sales price and the regression analysis to test which variables are related. The results of this study are summarized as follows : First, the cumulative abnormal return of stock is positive when government announced the deregulation of new apartment sales price. The cumulative abnormal return of stock for 21 trading day before -10 to +10 day is 25.51% which is significant different from zero at 1 percent level. This result suggests that the deregulation of new apartment sales price conveys good information to stock market that the firms performance will be good in the future. Second, in the regression analysis this study shows that the cumulative abnormal return of stock is related to firm's profit margin ratio.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.151-163
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• 2021

This paper is dealt with railway slope stability for slope reinforcement using a geosynthetic concrete composite mat(GCCM). Recently, according to a change in weather caused by global warming, train operation has been restricted by the loss of backfill slope at the roadbed, which is consists of gravel, due to typhoons and heavy rainfall. In addition, the amount of damage is getting more significant than the cost of restoration, and the safety of workers is worried. In order to improve this limitation, a slope stability analysis was applied with a rapid hardening composite mat so that it can quickly secure a construction surface with increased workability and work stability and reduce maintenance costs by preventing re-loss in case of heavy rain and fundamentally blocking vegetation. As a result of the analysis, it was confirmed that the increase in safety factor was confirmed when the rapid harding composite mat was applied.

• Journal of architectural history
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• v.32 no.1
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• pp.73-88
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• 2023

Recently, local studies looking at the 'local(region) as a whole' are gradually increasing. The study of local architectural history is important in that it provides specific information that encompasses the local and the entire and clues to three-dimensionalize the time and space in the local. To infer the 'presentness' of each era, reliable data in various fields are needed. Recently, as many databases (DB) and archives, from the 'National Archives of Korea' to other local archives, have been established and publicized, research resources in the local are growing rapidly in quantity and quality. Nevertheless, it is difficult to comprehensively check the data necessary to study the local architectural history(local architectural history research resources). Against this background, this study confirmed the trend of changes in the archive construction environment and the status and problems of local architectural history research resources in places that currently disclose local history research resources among generalized web-archives. Next, the relationship between the actual research on local architectural history was confirmed through the analysis of existing studies and the data used for Jeju. As a result, local studies, local archives, and local architectural history research agree with recent changes in local research trends, and the degree of archival construction has reached the same level as the available research resources except core data in local architectural history research. However, there is a problem that the density of information that can be used is low because the local architectural history research resources that can be obtained are fragmented because there are no archives and construction entities specialized in local architecture. As each archive has entered the stabilization and upgrading stage, the construction of new archives needs to be reconsidered, but it is time to find a detailed way to link related information quickly and accurately, such as private records, to reduce the gap in information needed in terms of research on local architecture and architecture history.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.655-661
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• 2005

For a hydro power plant project, the headrace tunnel having a finished diameter of 3.3m was constructed in volcanic rocks with well-developed vertical joint and high groundwater table. The intake facility was located 20.3 km upstream of the powerhouse and headrace tunnel of 20 km in length and penstock of 440 m in height connected the intake and the powerhouse. The typical caldera lake, Lake Toba set the geology at the site; the caving of the ground caused tension cracks in the vertical direction to be developed and initial stresses at the ground to be released. High groundwater table(the maximum head of 20 bar) in the area of well-connected vertical joints delayed the progress of tunnel excavation severely due to the excessive inflow of groundwater. The excavation of tunnel was made using open-shield type TBM and mucking cars on the rail. High volume of water inflow raised the water level inside tunnel to 70 cm, 17% of tunnel diameter (3.9 m) and hindered the mucking of spoil under water. To improve the productivity, several adjustments such as modification of TBM and mucking cars and increase in the number of submersible pumps were made for the excavation of severe water inflow zone. Since the ground condition encountered during excavation turned out to be much worse, it was decided to adopt PC segment lining instead of RC lining. Besides, depending on the conditions of the water inflow, rock mass condition and internal water pressure, one of the invert PC segment lining with in-situ RC lining, RC lining and steel lining was applied to meet the site specific condition. With the adoption of PC segment lining, modification of TBM and other improvement, the excavation of the tunnel under severe groundwater condition was successfully completed.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.57-65
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• 2023

The public safety management guidelines were introduced in 2019 and continue to be dedicated to advancing comprehensive measures for public safety management, with a primary focus on prioritizing the safety and well-being of the public within governmental institutions. To achieve this goal, our previous study developed a establishment procedure of risk assessment-based safety inspection system for public institutions that order construction projects and applied it to highway construction projects to evaluate its effectiveness. To enhance the practicality of the establishment procedure, it is essential to collect and analyze feedback from stakeholders regarding its performance and suitability. This study conducted a survey involving 200 participants who had experience with the establishment procedure, and performed statistical analyses to evaluate its performance and applicability. The survey results indicated that the participants reported a high level of satisfaction (scoring 4 and above on a 5-point Likert scale) in several areas: specialization of safety inspection items for different types of work (with a satisfaction rate of 65%), the evaluation process for safety ratings (64.5%), and their willingness to recommend the procedure to other institutions (75.5%). In the factor analysis with Varimax rotation, two factors emerged: (1) a specialization factor related to safety inspection items, and (2) a grading factor associated with safety evaluation results. Regression analyses of these factors unveiled significant positive relationships with improvements in safety and health performance, including the prevention of fatal accidents, heightened safety responsibility, and raised safety inspection standards. The establishment procedure of safety inspection system developed in our previous study can play a crucial role in reducing accidents resulting in fatalities and injuries at construction sites, ultimately contributing to a safer working environment for all involved parties.