• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.63-70
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• 2014

Deconstruction of the building must be applied firstly in order to improve recycling and reuse of construction wastes. In this study have done a case study for deconstruction of an apartment. All construction waste(CW) which will be generated during deconstruction was examined in each part of the building. Because drawing did not exist in most of the old building, we drew up floor plans of buildings. After analyzing these drawings, estimated quantities of CW. It was measured working time of labor and equipments for deconstruction and general demolition on each building of the apartment. In addition, it was proposed in the volume and weight per unit after analyzing detailed measurement of CW which was generated in the process of deconstruction and traditional demolition. It suggested recovery rate at a site, volume and weight conversion factors, and waste basic unit per area that based on the results of comparative analysis on the amount of CW which is calculated from drawing and generated at a site. These factors will be used fundamental materials for estimating quantities and treatment cost of CW, and scheduling of works.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.20-27
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• 2014

In the construction site, various earth retaining systems are developed and applied to maintain stability of excavated area and structures. Among the methods, the underground continuous wall and the column-type diaphragm wall methods are especially used in construction site nearby buildings or roads. However, these methods have some disadvantages such as the difficulty of quality control and long curing time because these methods need to cast fresh concrete at the construction site. In addition, these methods are usually applied to the site for the temporary purpose. In this paper, we suggest precast hollow prestressed concrete pile for continuous pile wall system. To investigate the structural behavior of suggested pile, which is the main member of the suggested system, tests pertaining to the structural behavior and prestressing force applied in the pile are conducted. From the test results, it was found that the prestressing force measured is sufficient compared with the value obtained by the design equation and the cracking moment measured is 34% higher than the design value. In addition to the above, this precast hollow prestressed concrete pile has an additional safety margin that the maximum moment is 59.2% higher than the cracking moment which is one of the serviceability limits for the design of the system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.11-20
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• 2022

The main purpose of this study is to investigate the applicability of the shear wave tomography technology as a non-destructive testing method to evaluate the debonding between the track concrete layer (TCL) and the hydraulically stabilized based course (HSB) of concrete slab tracks for the Korea high-speed railway system. A commercially available multi-channel shear wave measurement device (MIRA) is used to evaluate debonding defects in full-scaled mock-up test specimen that was designed and constructed according to the Rheda 200 system. A part of the mock-up specimen includes two artificial debonding defects with a length and a width of 400mm and thicknesses of 5mm and 10mm, respectively. The tomography images obtained by a MIRA on the surface of the concrete specimens are effective for visualizing the debonding defects in concrete. In this study, a simple image processing method is proposed to suppress the noisy signals reflected from the embedded items (reinforcing steel, precast sleeper, insert, etc.) in TCL, which significantly improves the readability of debonding defects in shear wave tomography images. Results show that debonding maps constructed in this study are effective for visualizing the spatial distribution and the depths of the debondiing defects in the railway concrete slab specimen.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.65-74
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• 2016

This study mainly focuses on urban regeneration project as a countermeasure to resolve climate change issues by analyzing the carbon-reduction effect of Jeonju test-bed cases. First, an urban regeneration project is designed for city, Jeonju by analyzing its environmental problems and potential improvement. Then, carbon emission and reduction amounts are evaluated for different businesses and scenarios. Carbon emission sources are classified according to a standard suggested by IPCC, and the emissions are calculated by various standard methods. The result shows that carbon emission amount in Jeonju test-bed is 102,149 tCO2eq. The fact that 70% of the emission from energy sector originates from buildings implies that urban regeneration projects can concentrate on building portions to effectively reduce carbon emission. It is also projected carbon emission will decrease by 3,826tCo2eq in 2020 compared to 2011, reduction mainly based on overall population and industry shrinkage. When urban regeneration projects are applied to 5 urban sectors (urban environment, land use, green transportation, low carbon energy, and green buildings) total of 10,628tCO2eq is reduced and 4,857tCO2 (=15.47%) when only applied to the green building sector. Moreover, different carbon reduction scenarios are set up to meet each goal of different sectors. The result shows that scenario A, B, and C each has 5%, 11%, and 15% of carbon reduction, respectively. It is recommended to apply scenario B to achieve 11% reduction goal in a long term. Therefore, this research can be a valuable guideline for planning future urban regeneration projects and relative policies by analyzing the present urban issues and suggesting improvement directions.

• Journal of the Korean Geotechnical Society
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• v.26 no.12
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• pp.19-30
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• 2010

Bentonite-based grout has been widely used to seal a borehole constructed for a closed-loop vertical ground heat exchanger in a geothermal heat pump system (GHP) because of its high swelling potential and low hydraulic conductivity. Three types of bentonites were compared one another in terms of viscosity and thermal conductivity in this paper. The viscosity and thermal conductivity of the grouts with bentonite contents of 5%, 10%, 15%, 20% and 25% by weight were examined to take into account a variable water content of bentonite grout depending on field conditions. To evaluate the effect of salinity (i.e., concentration of NaCl : 0.1M, 0.25M, and 0.5M) on swelling potential of the bentonite-based grouts, a series of volume reduction tests were performed. In addition, if the viscosity of bentonite-water mixture is relatively low, particle segregation can occur. To examine the segregation phenomenon, the degree of segregation has been evaluated for the bentonite grouts especially in case of relatively low viscosity. From the experimental results, it is found that (1) the viscosity of the bentonite mixture increased with time and/or with increasing the mixing ratio. However, the thermal conductivity of the bentonite mixture did not increase with time but increased with increasing the mixing ratio; (2) If bentonite grout has a relatively high swelling index, the volume reduction ratio in the saline condition will be low; (3) The additive, such as a silica sand, can settle down on the bottom of the borehole if the bentonite has a very low viscosity. Consequently, the thermal conductivity of the upper portion of the ground heat exchanger will be much smaller than that of the lower portion.

• Fire Science and Engineering
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• v.25 no.1
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• pp.50-56
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• 2011

In recently years, occurrences of lightning return strokes have been increased by global worming effect and intensity of lightning impulse voltage and current accompanied by lightning discharges has being strengthening. In Korea, 560 thousand lightning discharges happened in 200S. According to the increasing frequencies of lightning, human deaths and damages to the structure have been increased steadily. Electric fire caused by lightning return strokes due to the breakdown between power line and ground line from the ground potential rise on a process of the lightning impulse current through to the ground. The damages of lightning were occurring at same time in the neighboring areas of the lightning point. In order to protect from the lightning stroke, we made a suggestion to use protection devices and equipotential bonding at the dangerous areas. The analysis results of electric fires caused by lightning would be utilized to investigate and to find accurate fire cause in the fire scenes.

• Fire Science and Engineering
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• v.24 no.3
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• pp.1-8
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• 2010

This study is searched in the on actual condition and analysis about the fire fighting measure of 123 main wooden cultural properties designated by the Cultural Heritage Administration. First, the management of wooden cultural properties and the present condition of fire occurrence are arranged. Second, The field research and the information research of related government agencies are done from August. 2008 to October. 2008 about 123 main wooden cultural properties: Cultural properties designation classification, location classification, building area, number of possession cultural properties, present condition of fire fighting, a fire engine drive direction for fire suppression, number of self-defense fire brigade, fire administrator nomination, and the distance and time from a fire station are arranged in this study. Third, the inside and outside present conditions are classified and analyzed by average index for the fire occurrence risk of 123 main wooden cultural properties. And the basic data is arranged for the fire fighting measure of main wooden cultural properties.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.5
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• pp.1-10
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• 2008

A series of shaking table tests were conducted on a 1:12 scale model using scaled Taft N21E earthquake records to investigate the seismic performance of a 17-story high-rise reinforced concrete building structure with a high degree of torsional eccentricity and soft-story irregularities in the bottom two stories. The main characteristics of the behaviors were: (1) a sudden change of the predominant vibration mode from the mode of translation and torsion to the torsional mode after the flexible side underwent a substantial inelastic deformation; (2) an abrupt increase in the torsional stiffness during this change of modes; (3) a warping behavior of the wall in the torsional mode; and (4) a unilateral overturning moment in the transverse direction to the table excitations. In this study, efforts were made to simulate the above characteristics using a nonlinear analysis program, Perform3D. The advantages and limitations are presented with the nonlinear models available in this software, as they are related to the correlation between analysis and test results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.93-100
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• 2002

In this paper, in ordor to examine the relevant technical facts which are very instructive to revise the domestic standard for lightning protection systems, standards and technical guideline for the protection of structure against lightning were reviewed, and several issues of the domestic standards were experimentally investigated. As a consequence, the insulator of relatively low implse voltage and a large percentage of lighting rods is flashovered by relatively low impulse voltage and a lage percentage of lighting current flows through supporting mast. Thus the potential gradient in the vicinity of supporter for lighting rods is extremely increased and the role of lighting propection systems is nullified. It seems obvious that the flashover of insular supporting lighting rod can range from erratic operation of microelectronic devices to minor physical ham or even death, or costly damage electrical equipment.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.258-258
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• 2015

풍수해저감종합계획은 해당 지역의 풍수해 위험요인을 종합적으로 조사 분석하여 피해예방 및 저감을 위한 각종 구조적 대책과 비구조적 대책을 종합적으로 제시하는 방재분야 최상위 종합 계획이다. 풍수해저감종합계획은 자연재해대책법 제16조, 같은 법 시행령 제14조, 같은 법 시행 규칙 제4조의4에 따라 특별시 광역시 특별자치시 특별자치도 및 시 군에서 수립하고 있다. 또한 자연재해대책법 제16조 6항에서는 광역도시계획, 도시 군기본계획 및 도시 군관리계획의 수립 변경권자가 광역도시계획, 도시 군기본계획 및 도시 군관리계획을 수립하거나 변경하는 경우에는 시 군, 시 도 풍수해저감종합계획을 반영하도록하고 있다. 그러나 시설물 위주의 저감대책, 풍수해위험지구 정보의 한계, 풍수해위험지구의 자연재해위험개선지구 지정으로 인한 개별사업에 의한 재해저감 대책 수립 등의 이유로 현실적으로 반영이 잘 되지 못하고 있는 실정이다. 실제 경기도 도시기본계획의 방재 및 안전계획 부분의 풍수해저감종합계획과의 연계를 검토한 결과 대부분의 지자체가 방재대책과 관련하여서는 원론적인 측면에서만 언급하고 있는 것으로 나타났다. 본 연구에서는 풍수해저감종합계획의 도시계획에서의 활용도를 높이고자 하천, 내수, 사면, 바람, 해안재해 등 재해유형별로 풍수해의 직접적 발생과 풍수해 발생에 영향을 주는 공간적 영역, 개발 상태, 개발예정 등 토지이용현황 및 계획 등을 고려하여 풍수해중점관리구역, 풍수해선제관리구역, 풍수해전략관리구역으로 구분하여 설정하는 방법론과 활용방안을 제시하고자 하였다. 또한 도시계획 수립 시 풍수해관리구역을 어떻게 활용할 것인지에 대한 방안을 제시하였다. 향후 풍수해관리구역 지정과 관련한 법제도 및 지침 등이 마련된다면 풍수해관리구역은 풍수해저감을 위한 토지이용 및 기반시설, 건축물 제한 등 도시계획적 대책 마련에 적극적으로 활용될 수 있을 것으로 판단된다.