• Title/Summary/Keyword: 축 진단

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The Evaluation for Stability at Joint Part in Composition Dam (복합댐 접합부의 안정성 평가)

  • Kim, Jae-Hong;Oh, Byung-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.3
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    • pp.155-166
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    • 2008
  • Research dam is consisted of concrete gravity dam that right bank department is built to concrete material, left bank department is composition dam that is consisted of rockfill dam that consist of rockfill material In domestic case, composition dam form of storage of water facilities of about 17,000 does not exist hardly in dam of irrigation water industry drinking water purpose that manage local government or other institution, Even if exist, is real condition that there is total nonexistence administrator fare of facilities, Choose unique dam of domestic multipurpose dam and analyzed conduct special quality of con'c gravity dam and rockfill dam joint part To analyze dynamic conduct special quality of composition dam by analytic method in this research, Do modelling via axis of dam and achieved static(Psuedo-static, modify Psuedo-static) and dynamic analysis, When achieving earthquake response analysis, analyzed seismic response analysis between concrete part and rockfill's part.

Experimental Study on Shear Capacity of I-slab System Using Slim Precast Slab Deck (슬림 프리캐스트 슬래브 데크를 사용한 I-슬래브 시스템의 전단 성능에 관한 실험적 연구)

  • Kim, Seung-Hun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.1
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    • pp.126-133
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    • 2017
  • This paper presents the shear capacities of hollow slab with plate and octagonal pillar type hollow sphere. Recently, the interest in precast hollow slab system for buildings is growing up according to the demand for high quality control and the increase in slab thickness. A hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. However, hollow slabs are vulnerable to the deterioration in the shear strength due to the decrease of concrete at slab web which resists shear. Especially, in case of precast hollow slabs, it has joint surface between precast concrete slab modules along transverse axis of slab, and shear failure, that is caused by cracks at joints, has to be prevented. Therefore, in this study, shear capacity of the I-slab system is evaluated by 3-points-supported shear test along the longitudinal and transverse axis of slab specimen. Test results showed that I-slab had enough shear strength compared to theoretical shear strength even if it included the joint surfaces.

Structural Safety Evaluation by Analysis of Pressure Variation Characteristics of Small Hydro Power Hydraulic Turbine Blades in Sewage Treatment Plant (하수처리장 소수력 수차 블레이드의 압력변화 특성 분석을 통한 구조안전성 평가)

  • Park, Yoo-Sin;Kim, Ki-Jung;Youn, Byong-Don
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.6
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    • pp.126-131
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    • 2017
  • Numerical analysis using commercial CFD code was carried out to develop the drag force type vertical axis hydraulic turbine for the improvement of the production efficiency of small hydro energy at low flow velocity condition. Blade pressure changes and internal flows were analyzed according to the presence or absence of the hydraulic turbine blade holes at flow velocity of less than 1.0~3.0 m/s. According to the numerical results, the pressure and flow velocity is severly affected by the flow velocity in turbine blade with no holes, while the influence of flow velocity is comparatively decreased in turbine blade with holes. It is also found that the pressure and flow velocity on the blade surface with holes are evenly distributed with no singular location and it is believed that forming a hole in the blade may be helpful in terms of structural safety.

Nonlinear Analysis of Composite Basement Wall Using Contact Element (접촉면 요소를 사용한 합성 지하벽의 비선형 해석)

  • Seo, Soo Yeon;Lee, Chenggao
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.3
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    • pp.176-184
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    • 2007
  • The objective of this paper is to suggest a nonlinear analysis process to predict the structural behavior and strength of composite basement wall member combined with H-Pile. Therefore, the structural behavior of composite basement wall is studied and the special nonlinear characteristics of each elements such as H-Pile, concrete wall, and shear connectors are idealized using ATENA program. Finally, the result is compared with previous test result. Research result shows that there is a good co-relation between analysis and test results even if analysis result has little bit higher initial stiffness than test result. It can be concluded that the nonlinear behavior of composite basement wall is suitably predicted by using the contact element model in ATENA program as shear connector element.

Structural Performance of Y Type Plate Connection between Circular CFT Column and H Shape Steel Beam (Y형 플레이트를 적용한 원형 CFT 기둥-H형강 보 접합부의 구조성능)

  • Jo, Hyun-Kook;Choi, Chang-Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.6
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    • pp.112-118
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    • 2015
  • These days, there are lots of skyscrapers being constructed in downtown areas. However, it requires columns which have a way heavier load. and far more extensive cross sections of column as well. Therefore, it is hard to lay the foundation in downtown areas. This being the case, composite columns such as CFT column are primarily being used. However, CFT column is occurred of difficult beam-column connection development and lower performance since CFT column is closed cross-section. Especially, the result of the study concerning development of connection details with CFT column and exterior diaphragms are very low in current state. In this study, through developing CFT column-H shape steel beam applicating Y shape plate, set width and depth of Y shape plate which affect structural performance of connection details applicating Y shape plate as main variables, and evaluate structural performance through experiments. And also, design Y shape plate used at experiments as setting allowable stress for tension suggested at design criteria lower than axial force of tension side flange connected Y shape plate, through shape of destruction, verify the structural safety and performance of Y shape plate.

Vibration Reduction Effects of Stay Cable Due to Friction Damper (마찰댐퍼에 의한 사장 케이블의 진동저감 효과)

  • Kim, Hyung Ku;Yhim, Sung Soon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.2
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    • pp.54-61
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    • 2013
  • Stay cable has a strong axial rigidity due to large initial tension and, on the other hand, it has a weak laterally flexural rigidity. Wind loads or traffic loads cause the cables to vibrate significantly and affect the mechanical properties and the performance of cables of cable-stayed bridge (CSB). Therefore, the development of vibration reduction design is an urgent task to control the vibration vulnerable long-span bridges. As Friction damper (FD) shows to reduce the amplitude and duration time of vibration of cable of CSB from measured date in field test, friction damper can be considered that it is effective device significantly to reduce the amplitude and duration time in vibration of cable of CSB under traffic load, wind load and so on. Vibration characteristics of cable can change according to manufacturing method and type of established form. Nevertheless, analysis method in this study can present the design of friction damper for vibration reduction of cable of cable-stayed bridge from now on.

Modified Modulus of Elasticity of Concrete Column with Steel Bars (철근을 고려한 콘크리트 기둥의 수정탄성계수)

  • Yoon, Dong-Yong;Song, Hyung-Soo;Jang, Won-Seok;Min, Chang-Shik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.1
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    • pp.101-111
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    • 2005
  • In this study, it is investigated the modified modulus of elasticity of the reinforced concrete columns including the longitudinal reinforcing steels as well as the confinement effect of the core concrete due to the transverse reinforced steel through the literature reviews. Equations are derived in order to evaluate the modified modulus of elasticity for the reinforced compressive concrete including the confinement effect. The finite element analysis for the 20 story reinforced concrete building is undertaken as a case study depending on the steel ratio and modulus of elasticity, and the analysis results are discussed.

Virtual Bronchoscopy for Diagnosis of Tracheo-Bronchial Disease (기관지질환 진단을 위한 가상내시경)

  • Kim, Do-Yeon;Park, Jong-Won
    • The KIPS Transactions:PartB
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    • v.10B no.5
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    • pp.509-514
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    • 2003
  • The virtual bronchoscopy was implemented using chest CT images to visualize inside of tracheo-bronchial wall. The optical endoscopy procedures are invasive, uncomfortable for patients and sedation or anesthesia may be required. Also, they have serious side effects such as perforation, infection and hemorrhage. In order to determine the navigation path, we segmented the tracheo-bronchial wall from the chest CT image. We used the coordinates as a navigation path for virtual camera that were calculated from medial axis transformation. We used the perspective projection and marching cube algorithm to render the surface from volumetric CT image data. The tracheobronchial disease was classified into tracheobronchial stenosis causing from inflammation or lung cancer, bronchiectasis and bronchial cancer. The virtual bronchoscopy is highly recommended as a diagnosis tool with which the specific place of tracheobronchial disease can be identified and the degree of tracheobronchial disease can be measured qualitatively, Also, the virtual bronchoscopy can be used as an education and training tool for endoscopist and radiologist.

Experimental Study on Structural Performance of Recycled Coarse Aggregate Concrete Confined by Steel Spirals (나선철근으로 횡구속된 순환골재 콘크리트의 구조적 성능에 관한 실험적 연구)

  • Kim, Sang Woo;Jung, Chang Kyo;Lee, Sun Hee;Kim, Kil Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.1
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    • pp.103-111
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    • 2011
  • This paper estimated the structural behavior of recycled aggregate concrete confined with spiral reinforcement. The main test parameter was designed to be the type of aggregates and the steel ratio of spirals. A total of 18 specimens were cast and tested in this study. All the specimens had a diameter of 150mm and a height of 300mm. The specimens can be divided into two groups, based on the type of coarse aggregate used. The ratio of spiral reinforcement was varied from 0 % to 1.75%. To measure the axial and lateral deformations of the specimens, a total of six linear variation displacement transducers (LVDTs) were installed at each specimen. Furthermore strain gauges were also attached to the steel spirals to obtain the strain of spiral reinforcements. From the experimental results, the structural performance of recycled aggregate concrete specimens confined by steel spirals was similar to that of natural aggregate concrete specimens regardless of the ratio of spiral reinforcement.

Safety Evaluation on Interaction between Track and Bridge in Continuous Welded Railway Bridge Considering Seismic Load (지진하중을 고려한 장대레일교량의 궤도-교량 상호작용에 대한 안전성 평가)

  • Shim, Yoon-Bo;Kim, Yun-Tae;Kim, Sang-Chel
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.2
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    • pp.40-48
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    • 2016
  • To observe the rail-slab interaction in continuous welded railway(CWR) bridge when earthquake occurs, additional axial rail stresses and relative longitudinal displacements between rail and bridge deck were calculated with input of various load combinations and 3 different types of seismic loads to an analytical model. As results of analysis, it can be found that standard response spectrum proposed by Korea Rail(KR) network authority for earthquake design showed less additional axial rail stresses than allowable levels, but greater relative longitudinal displacement between rail and bridge deck, which means that adjustment of relative longitudinal displacement within a standard level is much more difficult than axial train stress. Additionally, if a large-scaled earthquake as occurred at Kobe, Japan comes up, then both of additional axial rail stress and relative displacement in rail-bridge deck may exceed allowable levels, which indicates to make proper design guides against sudden earthquake occurrence.