• Title/Summary/Keyword: Pipe Construction

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A Study on the Method of Analysis and Design of Benchmark Pile in Permafrost Area (영구동토지역에서의 수준말뚝의 안정성 검토 및 설계방법 연구)

  • Jo, Cheon-Hwan;Lee, Won-Je;Hong, Seong-Wan
    • Geotechnical Engineering
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    • v.9 no.2
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    • pp.15-26
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    • 1993
  • Frost heave on foundation(or ice jacking) is defined that foundation is uplifted by heav- ing force exerted around foundation from freezing of soils. This phenominon is often occurred in the light -weight structure e.g, small building, electro - telegraph pole, street light, pipe line, budge and reference point of survey. Frost heave is the most important factor in design of foundation of structure and the key issue in understanding mechanism of foundation in permafrost area. In this study is reviewed the state of the art on the analysis method of frost heave in USSR and is suggested the design method of benchmark pile. On the basis of above results, this study suggests a design chart able to do esign simply the benchmark pile in Yakutsk region.

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Reduction of the Flow Accelerated Corrosion within Low Pressure Evaporator Connection Pipe by Interception of Hydrazine for Water Treatment (탈산소제 차단 수처리에 의한 배열회수보일러 저압증기발생기 연결배관내의 유동가속부식 저감)

  • Son, Byung-Gwan;Lee, Jae-Heon
    • Plant Journal
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    • v.9 no.4
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    • pp.26-30
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    • 2013
  • Based on case that HRSG low pressure steam generator tube was damaged by FAC in 500 MW A CCPP. This case analyzed the effect of application about the block of hydrazine water treatment which is applied for increasing dissolved oxygen. And also try to deduce the major factor of FAC Which is caused by lacking of dissolved oxygen of boiler feed system. After 1 year of water treatment, the figure of dissolved oxygen in the boiler feed water has increased from 0.15 ppb to 3~5 ppb and the figure of oxidation reduction potential has increased from -245 mV to 170 mV. And Iron content, the corrosion products by FAC has decreased from 18.5 ppb to 5~7 ppb. According to the result of experiment, we could able to confirm that the interception of hydrazine of water treatment is effective to reduce FAC.

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Performance evaluation of a subsurface drainage culvert system in converted paddy fields

  • Do, Jong Won;Park, Jongseok;Kim, Hyuntai;Lee, Kwangya;Shin, Hyungjin
    • Korean Journal of Agricultural Science
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    • v.47 no.2
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    • pp.263-273
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    • 2020
  • With the change of the agricultural environment (increased rice production, decreased rice consumption, and rice production policies), converting paddy fields into upland fields is an increasing trend. In terms of conversion into upland fields, subsurface drainage is one of the most important factors for good field crop growth. This study evaluates the performance of a subsurface drainage culvert system in paddy fields and reclaimed lands. The obtained results are briefly summarized as follows: 1) After a comparative evaluation of several subsurface drainage culvert systems, including excavated subsurface drainage and non-excavated subsurface drainage types, type 3 (non-excavated, perforated drain pipe 50 mm, filter mat B50 cm, subsoiling 70 cm and culvert spacing 5 m) shows relatively high values among four types in terms of effectiveness (subsurface discharge capability) and economic efficiency (construction cost). 2) Type 3 has proven that it is suitable for design standards of discharge capacity through field tests performed in paddy fields (three sites: Gong-geom, Gae-san, Juk-san) and reclaimed lands (two sites: Gum-ho, Mi-am). 3) In the experiment of Sesamum indicum growth according to the existence of a drainage system, Sesamum indicum growth with a subsurface drainage culvert system had good value in terms of plant shoot and root length, shoot fresh and dry weight, and root fresh and dry weight).

An Analytical Study on Influence of Longitudinal Stiffeners on Seismic Performance of Circular Steel Columns (수직보강재가 원형강기둥의 이력거동에 미치는 영향에 대한 해석적 연구)

  • Jang, Gab-Chul;Chang, Kyong-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.7 no.1 s.23
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    • pp.63-70
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    • 2007
  • To improve the land use of urban, Construction of the circular steel column is required recently. The circular steel columns have a advantage for improving a load carrying rapacity as wall as reducing a effective section area. However, the circular steel columns under service load, such as earthquake, shows a tendency to cause local buckling and large deformation. To prevent these phenomena, use of longitudinal stiffeners is considered. The application of longitudinal stiffeners at the circular steel columns is expected to increase a load carrying capacity, buckling strength and seismic performance of circular steel column. However, increasing the loading carving rapacity of buckling which constructed the longitudinal stiffeners, was not investigated yet. Therefore it needs study on effect of longitudinal stiffener in pipe-section steel pier. In this study, the load rallying capacity of buckling of steel pier was investigated by using elastic-plastic finite element analysis considered geometrical and material non-linearity. Also, this study investigated the effect of longitudinal stiffeners on loading carrying capacity of buckling and the relationship between width and thickness of longitudinal stiffeners. And also, a Influence of longitudinal stiffeners on seismic performance of circular steel columns was investigated by numerical analysis

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A Evaluation on the Field Application of High Strength Concrete for CFT Column (고강도 CFT용 콘크리트의 현장적용성 평가 및 장기거동 예측)

  • Park, Je Young;Chung, Kyung Soo;Kim, Woo Jae;Lee, Jong In;Kim, Yong Min
    • Journal of the Korea Concrete Institute
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    • v.26 no.6
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    • pp.707-714
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    • 2014
  • CFT (Concrete-Filled Tube) is a type of steel column comprised of steel tube and concrete. Steel tube holds concrete and the concrete inside tube takes charge of compressive load. This study presents structural performance of the CFT column which has 73~100 MPa high strength concrete inside. Fluidity, mechanical compression, pump pressure test in flexible pipe were conducted for understanding properties of the high strength concrete. Material properties were achieved by various experimental tests, such as slump, slump flow, air content, U-box, O-Lot, L-flow. In addition, mock-up tests were conducted to monitor concrete filling, hydration heat, compressive strength. From construction sites in Sang-am dong and University of Seo-kang, long-term behaviors could be effectively predicted in terms of ACI 209 material model considering elastic deformation, shrinkage and creep.

Stress and Displacement Analysis of Arctic Frostheave with Gas Pipeline using Finite Element Method (극한지 동상융기에 의한 가스배관과 토양의 응력 및 변위 해석)

  • Kim, Kyung Il;Yeom, Kyu Jung;Oh, Kyu Hwan;Kim, Woo Sik
    • Journal of the Korean Institute of Gas
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    • v.19 no.5
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    • pp.47-53
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    • 2015
  • According to the interest of the arctic's resources rising, many countries are making moves to develop these resources. Korea has also undergone negotiations with Russia to develop natural gas resources in Siberia, which is geographically relatively close. However, the Arctic resources market is dominate, it is essential to develop construction techniques that are suited for the Arctic. Gas pipelines in the Arctic are affected by frost heave due to the region's extremely low temperatures, a condition that is not present in Korea, making it vital to develop a finite element method (FEM) model. This research paper study a model of gas pipe lines in the Arctic and frost heave using FEM.

The application of reliability analysis for the design of storm sewer (우수관의 설계를 위한 신뢰성해석기법의 적용)

  • Kwon, Hyuk Jaea;Lee, Kyung Je
    • Journal of Korea Water Resources Association
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    • v.51 no.10
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    • pp.887-893
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    • 2018
  • In this study, the optimum design technology is suggested by using reliability analysis method. Nowadays, urban flood inundation is easily occurred because of local heavy rain. Traditional deterministic design method for storm sewer may underestimate the size of pipe. Therefore, stochastic method for the storm sewer design is necessary to solve this problem. In the present study, reliability model using FORM (First Order Reliability Method) was developed for the storm sewer. Developed model was applied to the real storm sewers of 5 different areas. Probability of exceeding capacity has been calculated and construction costs according to diameter have been compared. Probability of exceeding capacity of storm sewers of 5 areas have been calculated after estimating the return period of rainfall intensity.

A Presentation on the Manual Hydraulic Calculation Method of the Loop Type Fire Sprinkler System (Loop형 스프링클러 설비의 수리계산 방법에 대한 제시)

  • Jeong, Keesin
    • Fire Science and Engineering
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    • v.29 no.1
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    • pp.73-79
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    • 2015
  • There are three kinds of design method of the fire sprinkler systems. Grid type is connected all branch as a trapezoid. Loop type is connected cross-mains like circle. The last one is a tree type most commonly used. Grid type needs computer program to calculate the friction loss and flow rate apart from very simple form. In loop type, manual calculation is possible. Design engineer can draw up and calculate the demands without computer program. Because water supplies two direction in loop type, friction loss is smaller than tree type. Water distribution in operation area is uniform because of the small differences of sprinklers discharge pressure. Loop type is superior to tree type in respect of total pressure and flow rate. Using the small diameter pipe, the labor and construction cost will be decreased in the end. Loop type sprinkler design is rarely laid out because design engineers don't know the method. This paper is intended to inform that the loop type is better than the tree type in performance and economic point of view. And also this paper intend to use the loop type easily and widely.

Construction of the Heat Pump System Using Thermal Effluents for Greenhouse Facilities in Jeju and Evaluation of Cooling Performance (제주 시설온실 냉난방을 위한 발전소 온배수 활용 열펌프 시스템 구축 및 냉방성능 평가)

  • Lee, Yeon-Gun;Heo, Jaehyeok;Lee, Dong-Won;Hyun, Myung-Taek
    • Journal of Energy Engineering
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    • v.27 no.4
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    • pp.70-79
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    • 2018
  • A heat pump system using the thermal effluent from the Jeju thermal power plant of KOMIPO was constructed with the capacity of 300 RT to supply cool or hot water to greenhouse facilities located 3 km from the power station. The way of transporting heat from the thermal effluent to greenhouses at a long distance was optimized, and a monitoring system to measure the water temperature and detect a leakage in a pipe conduit was also installed. This paper presents the system configuration of the constructed heat pump system for air conditioning and heating of greenhouse facilities in Jeju, and the characteristics of major components deployed in the system. The preoperational tests of the heat pump system were conducted during the summer season in 2018 for evaluation of its cooling performance. The operational stability and cooling performance of the heat pump system were confirmed by investigating the measured fluid temperature and flow rate, and COP of the heat pump in a cooling mode.

A Study on the Simulation of Underground Acoustic Telemetry (지중 원격 음파통신 시뮬레이션 연구)

  • Shin, Younggy
    • Plant Journal
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    • v.18 no.2
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    • pp.41-45
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    • 2022
  • The conventional communication method using mud flow pressure waves has a speed of 1-2 bps, so it takes a long time to communicate, making real-time control impossible. Although the sound wave communication method for improving the communication speed by 10 times or more has been commercialized, its use is limited due to its high price and there are not many application cases. In this study, the simulator corresponding to the facility was developed to develop performance similar to the actual test results. For simulating sound wave communication through a drill pipe, we proposed a governing equation that can simulate friction damping by mud and developed a numerical analysis model. The attenuation factor was corrected by comparing it with the attenuation rate of sound wave energy at the drilling site. The developed numerical analysis model was applied to the QPSK modulation type communication algorithm to confirm the excellent performance of the communication error rate of 0.04% in the ground. This is the communication performance under the condition that noise has not been mixed yet, and in order to apply it, the technology of reproducing the actual noise signal for mixing by securing the field noise data was established.

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