• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.317-324
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• 2020

In this study, a simplified equation for settlement evaluation suitable for the special conditions of a counter facility is suggested. Recently, counter facilities, especially breakwaters, are constructed on soft ground in distant seas as new-port development projects. A counter facility that resists the external forces by self-weight settles easily when constructed on soft ground. Settlement in a counter facility and breakwater is not an important factor for maintenance than a land facility. On the other hand, the current settlement evaluation criteria are excessive for conducting a safety inspection. A settlement evaluation from a safety inspection followed by "Detailed Guidelines for a safety inspection on a counter facility" is used. A simplified equation was proposed to calculate the maximum settlement by applying the allowable residual settlement or settlement stability evaluation results. The suitability of the simplified equation was assessed compared to the assessed rating from the settlement survey results. The proposed simplified equation showed that the settlement evaluation rating had been upgraded. The proposed simplified equation is expected to be used to evaluate the practical structural stability and functional performance.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.505-514
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• 2009

This paper describes the structural behavior and the ultimate strengths of circular hollow steel (CHS) sections based on a series of compression tests. The ultimate strengths of CHS section columns are mainly dependent on both diameter-thickness ratio and column slenderness ratio. For the CHS sections with a high diameter-thickness ratio, an elastic or an inelastic local buckling may occur prior to the overall buckling, and it may decrease the column strength. Test sections were fabricated from SM400 steel plate of 2.8 mm and 3.2 mm in thickness and were tested to failure. The diameter-thickness ratios of the test sections ranged from 45 to 170 to investigate the effect of local buckling on the column strength. The compression tests indicated that the CHS sections of lower diameter-thickness ratio than the yield limit in the current design specifications showed an inelastic local buckling and a significant post-buckling strength in the local mode. Their ultimate stresses were larger than the nominal yield stress. It was known that the allowable stresses of the sections predicted by the Korean Highway Bridge Design Specifications (2005) were too conservative in comparison with test results. The Direct Strength Method which was newly developed was calibrated for application to the CHS sections by the experimental and numerical results. The Direct Strength Method proposed can predict properly the ultimate strength of CHS section columns whether a local buckling and an overall buckling occur nearly simultaneously or not.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.21-28
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• 2017

The steel-plate concrete(SC) is used in a form of module assembly construction in the outer wall of nuclear-power plant and LNG containment. Since the steel-plate concrete modules are generally manufactured from the plant, the weight of SC has significantly effect on the total construction cost in the aspect of shipment. Therefore, the use of lightweight aggregates concrete(LWAC), which fill the inside of SC module can be a solution. However, the amount of used lightweight aggregates(LWA) is limited in the use of current concrete mixing process due to the concrete quality problems and it also determines the allowable minimum density of LWAC. In this research, the preplaced casting method is applied because of increasing the volume fraction of LWA significantly, which results from the producing process of pre-packing the LWA in the formwork and filling the interstitial voids between LWA using cement paste grout. The density and compressive strength of selected preplaced LWAC were $1,600kg/m^3$ and 30MPa and it was applied for the mock-up specimens of SC panel. It was used for the 3-point bending test for evaluating its structural performance. The results show that the preplaced LWAC can reduce the density of concrete with the adequate mechanical and structural performance.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.1
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• pp.45-54
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• 2008

A new proposed repository has a final capacity of 800,000 drums radioactive waste. Most of foreign repositories have a general practice of segregating control zones which mainly contributes to classification of degree of control, whether it is called buffer zone or not. Domestic regulatory requirements of establishment of buffer zone in a repository are not much different from those of nuclear power plants for operation period, in which satisfactory design objective or performance objective is the most important factor in determination of the buffer zone. The meaning of buffer zone after closure is a minimum requested area which can prevent inadvertant intruders from leading to non-allowable exposure during institutional control period. Safety assessment with drinking well scenario giving rise to the highest probability of exposure among the intruder's actions can verify fulfillment of the buffer zone which is determined by operational safety of the repository. At present. for the repository to be constructed in a few years, the same procedure and concept as described in this paper are applied that can satisfy regulatory requirements and radiological safety as well. However, the capacity of the repository will be stepwise extended upto 800,000 drums, consequently its layout will be varied too. Timely considerations will be necessary for current boundary of the buffer zone which has been established on the basis of 100,000 drums disposal.

• Journal of Environmental Impact Assessment
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• v.16 no.4
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• pp.301-310
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• 2007

For the improvement of air quality in the metropolitan area, Korea has enforced the air pollutant emission cap regulation from the 1st of July, 2007, and the companies that intend to install a new or an enlarged facility in the metropolitan area will be restricted. However, the current regulation on permission does not describe a standard of judgement distinctly. In this study, therefore, a method of permission on the installation of a new or an enlarged facility was developed by supplementing the law in force based on the foreign cases. To develop a specific permit regulation and procedure, the developed nations' cases such as US, Canada, EU were reviewed thoroughly. Also, an appropriate method was suggested to apply domestically for a new or an enlarged facility permit within the regulations of the metropolitan special law. The method consists of first, calculating the possible permit quantity from the difference between an estimated annual emission cap and the annual emission provided by the implementation plan in each region. Second, permitting a new or an enlarged facility construction within the difference of the emission between the regional emission cap and the implementation plan in 2014. Third, distributing emissions allowable to each performance year based on the regional emission cap and the implementation plan in 2014. Fourth, making use of the emission difference between the implementation plan and the performance result in each year. Considering the general domestic conditions, the convenience of the permit authority and permitted companies, the most reasonable method was to use the fourth. To enforce the suggested permit method in a more flexible way, parts of the related regulations need to be revised and continuous research and analysis on the results from the implemented system and on foreign cases is necessary to develop this method a suitable system for domestic conditions and to settle the air pollutant emission cap system.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.685-691
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• 2007

In this paper through Honan high-speed railroad which is planned with the north and south axis, we will verify the feasibility of the coordinate conversion using railroad control points after regarding current planned-railroad as the linear central axises. From analysis, distortion of Y axis varies 21 cm to 40 cm diminishing to a gentle straight line, distortion of X axis varies 14 cm to 29 cm. Through a revision, the deviation value between the coordinates were 6 mm to 9 mm and it satisfied the allowable error of national geographic information institute which is following ITRF (International Terrestrial Reference Frame) and cadastral boundary survey (10 cm). consequently the coordinate conversion is possible using railroad control points as common control points.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.41-52
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• 2005

Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need fur cable backfill materials that can maintain a low thermal resistivity even while subjected to high temperatures for prolonged periods. Temperatures greater than $50^{\circ}C\;to\;60^{\circ}C$ may lead to breakdown of cable insulation and thermal runaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aimed at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. Tests were carried out for Dongrim river sand, a relatively uniform sand of very high thermal resistivity, $50^{\circ}C-cm/watt\;at\;10\%$ water content, $260^{\circ}C-cnuwatt$ when dry, and Jinsan granite screenings, and D-2 (sand and granite screenings mixture), E-1 (rubble and granite screenings mixture), a well-graded materials with low thermal resistivity, about $35^{\circ}C-cm/watt$ when at 10 percent water content, $100^{\circ}C-cm/watt$ when dry. Based on this research, 3 types of backfill materials were suggested for improved materials with low thermal resistivity and the applicability was assessed through field tests.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.5
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• pp.529-545
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• 2012

Three-dimensional (3D) finite element analyses have been performed to study the behaviour of a single pile to open face tunnelling in stiff clay. Several key factors such as tunnelling-induced ground and pile settlement, and shear transfer mechanism have been studied in detail. Tunnelling resulted in the development of pile settlement larger than the Greenfield soil surface settlement. In addition, due to changes in the shear transfer between the pile and the soil next to the pile with tunnel advancement, axial force distributions along the pile change drastically. The apparent allowable pile capacity was reduced up to about 30% due to the development of tunnelling-induced pile head settlement. The skin friction on the pile was increased with tunnel advancement associated with the changes of soil stresses and ground deformation and hence axial pile force distribution was reduced. Maximum tunnelling-induced tensile force on the pile was about 21% of the designed pile capacity. The zone of influence on the pile behaviour in the longitudinal direction may be identified as ${\pm}1$-2D (D: tunnel diameter) from the pile centre (behind and ahead of the pile axis in the longitudinal direction) based on the analysis conditions assumed in the current study. Negative excess pore pressure was mobilised near the pile tip, while positive excess pore pressure was computed at the upper part of the pile. It has been found that the serviceability of a pile experiencing adjacent tunnelling is more affected by pile settlement than axial pile force changes.

• Journal of Distribution Science
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• v.13 no.7
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• pp.41-51
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• 2015

Purpose - This study analyzes loading efficiency by loading pattern for package standardization and reduction of logistics costs, along with the creation of revenue for the revenue review panel (RRP) of Membership Wholesale Clubs (MWC). The study aims to identify standard dimensions that can help improve the compatibility of the pallets related to display patterns preferred by the MWC and thereby explore ways to enhance logistics efficiency between manufacturers and retailers through standardization. Research design, data, and methodology - The study investigates and analyzes the current status based on actual case examples, i.e., manufacturer A and Korea's MWC (A company, B company, and C company), and thus devises improvement measures. To achieve this, the case of manufacturer A delivering to MWC was examined, and the actual pallet display patterns for each MWC were investigated by visiting each distribution site. In this study, TOPS (Total Optimization Packaging Software, USA) was used as the tool for pallet loading efficiency simulations the maximum allowable dimension was set to 0.0mm to prevent the pallet from falling outside the parameters, and the loading efficiency was analyzed with the pallet area. In other words, the study focused on dimensions (length x width x height) according to the research purpose and thereby deduced results. Results - The analysis of pallet loading patterns showed that the most preferred loading patterns for loading efficiency according to product specification, such as pinwheel, brick, and block patterns, were used in the case of the general distribution products, but the products were configured with block patterns in most cases when delivered to MWCs. The loading efficiency by loading pattern was analyzed with respect to 104 nationally listed standard dimensions. Meanwhile, No.51 (330 × 220mm) of KS T 1002 (1,100 × 1,100mm) was found to be the dimension that could bring about an improved loading efficiency, over 90.0% simultaneously in both the T-11 and T-12 pallet systems in a loading pattern configuration with the block pattern only, and the loading efficiency simulation results also confirmed this as the standard dimension that can be commonly applied to both the T-11 pallet (90.0%) and the T-12 pallet (90.7%) systems. Conclusions - The loading efficiency simulation results by loading pattern were analyzed: For the T-11 pallet system, 17 standard dimension sizes displayed the loading efficiency of 90.0% or more as block patterns, and the loading capacity was an average of 99.0%. For the T-12 pallet system, 35 standard dimension sizes displayed the loading efficiency of more than 90% as block patterns (the average loading efficiency of 98.6%). Accordingly, this study proposes that the standard dimensions of 17 sizes with the average loading efficiency of 99.0% should be applied in the use of the T-11 pallet system, and those of 35 sizes with the average loading efficiency of 98.6% should be reviewed and applied in the use of the T-12 pallet system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.38-46
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• 2012

This study carried out current status, characteristics, and problems of coastal environment management on semi-enclosed Masan Bay in Korea and suggests cost-effective and eco-friendly water quality management policy. The pollutants from terrestrial sources into the Bay have apparently environmental pollution problems, such as eutrophication, red tide, and hypoxia. The carrying capacity of the Bay is estimated by hydrodynamic model and ecosystem model, material circulation including bivalve in ecosystem is analyzed by the growth model of bivalve. The resulting reduction in the input load was found to be 50~90%, which is unrealistic. When the efficiency of water quality improvement through bivalve farming was assessed based on the autochthonous COD, 30.7% of the total COD was allochthonous COD and 69.3% was autochthonous COD. The overall autochthonous COD reduction rate by bivalve aquaculture farm was found to be about 6.7%. This study indicate that bivalve farming is about 31% less expensive than advanced treatment facilities that remove both nitrogen and phosphorous.