• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.121-129
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• 2017

In this paper, the shake table test for the masonry infilled reinforced concrete frame with non-seismic details was carried out in order to evaluate its dynamic behaviour and damage under seismic condition. The tested specimens were the RC frame and the masonry infilled RC frame and the dynamic characteristics, such as a resonant period, acceleration response, displacement response and base shear force response, were compared between them. As a result of the shake table test, RC frame specimen had flexural cracks at the top and bottom of the column and shear cracks at the joints. In the case of masonry infilled RC frame, the damage of the frame was relatively minor but the sliding cracks and diagonal shear cracks on the masonry wall were severe at the final excitation. The resonant period of infilled RC frame specimen was shorter than that of the RC frame specimen because the masonry infill contributed to increase the stiffness. The maximum displacement response of the infilled RC frame specimen was decreased by about 20% than the RC frame specimen. It was analyzed that the masonry infill wall applied in this study contributed to increase the lateral strength of the RC frame with non - seismic detail by about 2.2 times and the stiffness by about 1.6 times.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.19-26
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• 2017

Concrete is a construction material with porous media and corroded steel inside affects negatively to durability and structural safety. This study aims a derivation of quantitative relationship between measured HCP (Half Cell Potential) and corrosion amount considering cover depth and W/C (water to cement) ratio. For the work, cement mortar specimens with 3 different W/C ratios and 4 different cover depths are prepared, HCPs are measured with 3 different corrosion level. HCP measurement significantly increases in the saturated condition and linear relationship is observed between corrosion level and acceleration period. With increasing corrosion level and W/C ratio, and decreasing cover depth, HCP measurement increases. Considering total corrosion level and HCP measurements, relatively low COV(Coefficient of Variation) of 0.67 is evaluated through multi-linear regression analysis, however higher COVs over 0.90 can be obtained considering level of HCP measurement. In the room condition, corrosion level can be evaluated through measured HCP in the given conditions of cover depth, W/C ratio. diameter of steel inside.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.485-498
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• 2015

Structural analysis for a large-scale fault in Maegok-dong, Ulsan, was carried out based on filed-works to investigate the geometric and kinematic characteristics of the fault as well as its Quaternary slip. As results, a series of repeated stratigraphy, minor faults, fracture zones, and deformation band clusters are observed over a distance of about 100 m in the first studied site consisting of sedimentary rocks, which may indicate the damage zone of a large-scale fault in this site. In the second site, mainly composed of granitic clastic rocks, a large-scale thrust fault is expected based on low-angle dipping faults showing branched and/or merged patterns. Age of the last slip on this fault was restrained as after 33,275 ± 355 yr BP based on radiocarbon dating for organic material included in the gouge zone. Dimension of fault damage zone, dominant sense of slip, and age of the slip event associated with the fault suggest that these structures have a close relationship with the Ulsan Fault and/or Yeonil Tectonic Line, which are well-known large-scale neotectonic structural features around the study area. Therefore, it is necessary to study the characteristics of the faults in detail based on structural geology and paleoseismology in order to ensure seismic and geologic stability of the buildings under construction, and to prevent geologic hazards in this area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1991.06a
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• pp.37-44
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• 1991

영산강 하구언 방조제의 건설로 인한 항만 및 이의 인접해역 해면의 변화는 예상한 바 있으며 실제 여러개소에서 월 2회정도의 주기로 목포 구항부근 상업지역에서 해면상승에 따라 주기적으로 침수되는 현상이 나타나고 있다 목포항의 영산강 하구언 방조제 조성으로 인한 조류성분중 최고기록을 가진 수로에서는 6kts 정도로 감소된 것으로 보고되고 있으나 주위자연환경 변화에 따른 수면 상승 및 해수면의 주기적인 변화 등에 대한 상세한 언급 및 깊이 있는 분석은 회피되어왔다. 수자원의 효율적관리를 위해 하구언 방조제는 이미 건설되었고 앞으로 대규모의 항만개발과 대불산업단지조성을 위해 추가 3개의 만입해안해역에 댐으로 해역을 막아 매립공사를 추진하고 있다 그러나 이 지역에 대한 분석은 타당성의 여부만을 강조한 상업적 용역이 이루어지고 있고 장래 개발에 대해 학술적이고 실질적인 문제점 추출과 해결방아네 대해서는 무시하거나 경시한 바가 많다 더구나 태풍 저기압 등과 같은 자연재해를 고려한 분석은 시도되지 못하고 있다 따라서 개발전후의 현상에 대한 상세한 자료 및 현장 조사와 극한 상태를 고려하여 개발에 따른 수위상승 부진동, 조류 수질등 이해역의 변화요소를 수집하고 분석하며 과학적 접근방법에 기초를 둔 수치모델의 실험을 포함하여 현장관측 및 측정자료를 검증하는 것이 필수적이라고 사료되어 종합분석의 한단계로 여기서는 하구언 및 하구간척(Land Reclamatic of Estuary barren)으로 해역축소에 따른 해면변화의 실제현상을 조사하여 정리하고 이를 수치모델을 통해 시뮬레이션하여 보았다 이는 종합개발의 좋은 기초자료로 이용됨은 물론이로 이지역의 개발에 기여할 것으로본다.적절하게 가정된 지반의 응력-변형률 관계와 간극수압특성에 의하여 고려되었다. 그 결과 응력 및 변위가 심하게 발생하는 지역은 황색 점토층이었으며 이로부터 황색 점토층에서 부터 파괴면이 생성되어 다른 지역으로 전파되었음을 유추할 수 있었다.form trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of ca

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.57-65
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• 2013

The development of the oil refining industry has resulted in an annual 120 million tons of sulphur, which is a by-product of the desulphurization process. To exploit this abundance, the applications of sulphur must be expanded. as excellent durability of reuse of leftover sulphur which has high potential for utilization in construction materials, the study is actively in progress. Meanwhile, there has been active research on semi-rigid pavements that draw on the strengths and overcome the weaknesses of asphalt and concrete pavements. Acrylate is used to prevent cracking but involves a high cost, thus, an alternative material is required. As such, this study presents methods on the reuse of leftover sulphur and examines the engineering performance of grout containing sulfur polymer emulsion (SPE) for use in semi-rigid pavements. Our analysis shows that grout in which 30% of acrylate is replaced with SPE has superior properties in terms of time of flow and strength compared to regular grout. However, performance declined when more than 50% of acrylate was replaced by SPE, indicating that the optimum replacement level is 30%. Through SEM analysis, we found that grout with utra harding cement in this study at three hours had similar hydration properties to that of Type 1 Ordinary Portland Cement (OPC) at seven days, and maintained the properties regardless of grout containing SPE. OPC and grout with a replacement level of 30% displayed similar levels of chloride invasion resistance, whereas grout without SPE was far less resistant. Within the scope of this paper, the optimum replacement level of acrylate with SPE was found to be 30% in consideration of various properties such as time of flow, strength, and chloride invasion resistance.

• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.51-55
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• 2010

The global activities to reduce the $CO_2$ emission as a greenhouse gas have been various efforts. Under this circumstance, small and medium sized gas field containing $CO_2$ to develop as LNG is not economic feasibility. Particularly, for the separation of $CO_2$ in gas field, separation facilities should be installed to add. This is and increase in plant construction cost and separated $CO_2$ emission into the atmosphere is not the result of greenhouse gas reduction. When the uneconomic gas field apply the KOGAS DME process, the gas field containing $CO_2$ can be increase economic feasibility because of natural gas and $CO_2$ can be use to resource gas. The Tri-reformer produced syngas as H2 and CO in KOGAS DME process and the resource gases are natural gas, steam, oxygen and $CO_2$. The $CO_2$ is used as raw material gases from recover $CO_2$ in DME process. In this study, we investigated range of application of $CO_2$ in gas field.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.121-129
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• 2017

There have been a number of water and sewer pipe breakdown reports followed by ground subsidence. Also, the excavating works for construction due to overcrowding of city have been common. Particularly, in urban areas ground becomes unstable because of the lowered lifeline sinkage followed excavation and backfilling. In order to solve the problem, some reinforcement works for ground by rod tamping or grouting have been applied. However, it is hard to predict when the buried utilities in underground will be damaged. Also, there is a limit for the underground exploration and investigation methods. Therefore, in this study, the estimated about the water soluble polymer pouch including poor mixed admixture which is designed to eliminate the dangerous factors. The reinforcement strength of this method was confirmed by verifying three points: meltiness in a certain period, water solubility in the ground water level, and characteristics of the pouch, which can be stored in daily conditions. It is also proved that this method allows to keep the ground from getting weakened in the installation of water and sewer pipe along with back filling materials.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.130-137
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• 2012

This study has conducted to develop new gabion wall systems with vegetation base materials for stream bank stability and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Normally gabion wall systems resist the lateral earth pressures or stream power by their own weight. Therefore, fill material must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones are basically specified, and about 50-mm rubbles are also used. Test application of new gabion wall system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the analysis of hydraulic stability of new gabion wall system, gabion wall system has highest threshold shear stress when the gabion wall covered by vegetation. New gabion wall system is highly resistant to sliding and overturning because safety coefficients exceed 1.5. As a result of term of slope stability analysis of new gabion wall system by Bishop and Fellenius methods, stability of stream bank was highly increased after the construction of gabion wall. Therefore, new gabion wall system is effective to stabilize unstable stream bank.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.423-430
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• 2013

An algorithm to allow shoreline movement during numerical experiment on sediment transport, deposition or resuspension for general coastal morphology is proposed here. The bed slope near shoreline, i.e. mean sea level, is influenced by bed material, tidal current, waves, and wave-induced current, but has been reported to remain within a stable range. Its annual variation is not large, either. The algorithm is adjusting the bathymetry, if the largest bed slope within shoreline band exceeds a given bed slope due to continuous erosion at zones below the shoreline. This algorithm automatically describes retreat of shoreline caused by erosion, when used within a numerical system. The algorithm was tested to a situation which includes a continuous dredging at a point, and showed satisfactory development of concentric circle contours. Next, the algorithm was tested to another situation which includes sinking of eroded part of bed plate, and produced satisfactory results, too. Finally, the algorithm was tested to a movable-bed laboratory experimental conditions. The shoreline movement behind detached breakwater was reasonably reproduced with this algorithm.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.236-242
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• 1998

While bacteriophage P2-P4 system is very useful experimental tool for the study of viral capsid assembly, there is no useful plasmid vector for the DNA manipulation in bacteriophage P2-P4 system. In this study, a new vector plasmid, P4 ash8 (sid71) kmr, was constructed by swapping the non-essential region of P4 DNA for kanamycin resistance(kmr) gene cassette of plasmid pUC4-K. P4 ash8 sid71 was starting material for the construction, since it tends to be maintained as a plasmid in the absence of the helper phage. The total size of this chimera was designed to be packaged into P4 or P2 size heads with induction by P2 infection. The conversion of plasmid P4 ash8 (sid71) kmr to bacteriophage was proved by burst size determination experiment and CsCl buoyant equilibrium density gradient experiment. Integrase destructed P4 derivative, P4 ash8 sid71 kmr intS, was able to be constructed easily by in vitro DNA manipulation of P4 ash8 sid71 kmr. The plasmid stability experiment with P4 ash8 sid71 kmr if/tS showed that the integrase of P4 affects the stable maintenance of plasmid P4 state.