• Title/Summary/Keyword: Maintenance Capacity

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Displacement Dependency and Capacity Evaluation According to the Cross-Sectional Shape and Aspect Ratio of Steel Rod Dampers (강봉댐퍼의 단면형상과 형상비에 따른 변위의존성 및 성능 평가)

  • Hyun-Ho Lee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.5
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    • pp.89-96
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    • 2023
  • In this study, the displacement dependence, strength, and energy dissipation capacity of the steel rod damper were evaluated. The test variables were cross-sectional shape and aspect ratio. The 6th test specimens were made for performance test. From the test results, it was evaluated that the displacement dependence conditions of design code were satisfied in all specimens. And the strength effect according to the cross-sectional shape was minimal. As a result, the strength and energy dissipation capacity of the aspect ratio of 13.7 were evaluated as excellent.

Experimental Study on Performance Evaluation of Steel Frame with Buckling Control Brace (좌굴제어 가새를 가진 가새골조의 성능향상에 관한 실험적 연구)

  • Lee, Sang-Ju;Han, Sang-Eul;Noh, Sam-Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.5
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    • pp.181-188
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    • 2007
  • This research presents two methods to prevent local buckling from circular tube brace and then verify their performance capacity through a cyclic loading test. As control methods on local buckling, one is to restrict local buckling as attaching cover plate at range of buckling. And the another is to exclude danger of buckling as inserting contraction device with rod and spring at the center of brace. The purpose of this research is to develop structural device for restriction of local buckling or for exclusion of its. And we investigate appliance of suggested methods through an experiment. We also estimate the improvement of performance capacity in a quantitative respect.

Load Transfer Capacity for the Planar Joints between Existing Slab Retrofitted with Carbon Fiber Plate and New Slab (탄소판으로 보강된 기존 슬래브와 신규 슬래브 접합부의 횡방향 하중전달 능력)

  • Kim, Seung Hun;You, Young Chan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.2
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    • pp.117-124
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    • 2007
  • An experimental research has been performed to evaluate the load transfer capacity for the planar joints between existing and new slab in an apartment remodelling constructions expecially for enlarging the interior space. Post-installed dowel bars were used as a joint connector. The existing slabs were obtained from the existing apartment housing which will be demolished, and were retrofitted with carbon fiber plate. Test results showed that the planar joints with post-installed dowel bars behaved in full composite modes until ultimate capacity of test specimens, so sufficient ultimate and serviceability performance are confirmed.

An Experimental Study on Strengthening Performance of RC Slab used of Surface Bonded Method of GSP and CFRP Sheet (GSP와 CFRP 쉬트의 표면부착공법을 이용한 RC 슬래브의 보강성능 평가에 관한 실험적 연구)

  • Ahn, Ki-Man;Kim, Kwang-Soo;Park, Sun-Kyu;Lee, Young-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.6
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    • pp.95-102
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    • 2007
  • Recently, an improved capacity for RC bridges is required by their deterioration or necessary to carry traffic increase. Strengthening is known as a better way to improve capacity of bridges than reconstructing in terms of economy. The surface bonded method, which is normally used with FRP material, has some advantages related to conveninent application and time-save among other strengthening methods. FRP material is light and has high tensile strength compared to steel. Therefore, this paper presents how structural capacity strengthed with CFRP sheet and Glass fiber-Steel Plate (GSP) is improved.

Analytical Study on the Seismic Capacity for Existing Masonry Building in Korea (국내 기존 조적조 건축물의 내진성능에 관한 해석적 연구)

  • Heo, Jae-Sang;Lee, Sang-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.6 s.58
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    • pp.75-87
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    • 2009
  • In this study, FEM analysis has been performed based on the results from domestic experimental researches regarding to material and member characteristics of masonry. After validation of reliability for the used FEM analysis method, this study is progressed the evaluation of seismic capacity for existing prototype masonry building in Korea. According to the evaluation for the prototype masonry building, the horizontal shear force and the average shear stress are similar to those of previous studies.

Evaluation of Bearing Capacity on PHC Auger-Drilled Piles Using Artificial Neural Network (인공신경망을 이용한 PHC 매입말뚝의 지지력 평가)

  • Lee, Song;Jang, Joo-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.6
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    • pp.213-223
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    • 2006
  • In this study, artificial neural network is applied to the evaluation of bearing capacity of the PHC auger-drilled piles at sites of domestic decomposed granite soils. For the verification of applicability of error back propagation neural network, a total of 168 data of in-situ test results for PHC auger-drilled plies are used. The results show that the estimation of error back propagation neural network provide a good matching with pile test results by training and these results show the confidence of utilizing the neural networks for evaluation of the bearing capacity of piles.

Hysteretic Behavior of Slab-Column Joint Using Bended Type Shear Reinforcement (절곡형 전단보강근을 사용한 슬래브-기둥 접합부의 이력 거동)

  • Lee, Hyun-Ho;Lee, Do-Bum;Lee, Li-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.3
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    • pp.211-218
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    • 2006
  • From the development of residential flat plate system, continuously bended shear reinforcement is developed for the prevention of punching shear. To know the punching shear capacity of developed shear reinforcement in slab-column joint, structural test is performed. The testing parameters are shear reinforcement types, such as no reinforcement, bended shear reinforcement, and head stud reinforcement. To verify the lateral capacity, cyclic load is applied under the constant vertical load condition. The results of tests are compared to as global displacement, slab-column joint strength. From the test results, the resisting capacity of developed shear reinforcement system has a good performance in the story drift ratio.

ISO Coordination of Generator Maintenance Scheduling in Competitive Electricity Markets using Simulated Annealing

  • Han, Seok-Man;Chung, Koo-Hyung;Kim, Balho-H.
    • Journal of Electrical Engineering and Technology
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    • v.6 no.4
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    • pp.431-438
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    • 2011
  • To ensure that equipment outages do not directly impact the reliability of the ISO-controlled grid, market participants request permission and receive approval for planned outages from the independent system operator (ISO) in competitive electricity markets. In the face of major generation outages, the ISO will make a critical decision as regards the scheduling of the essential maintenance for myriads of generating units over a fixed planning horizon in accordance with security and adequacy assessments. Mainly, we are concerned with a fundamental framework for ISO's maintenance coordination in order to determine precedence of conflicting outages. Simulated annealing, a powerful, general-purpose optimization methodology suitable for real combinatorial search problems, is used. Generally, the ISO will put forward its best effort to adjust individual generator maintenance schedules according to the time preferences of each power generator (GENCO) by taking advantage of several factors such as installed capacity and relative weightings assigned to the GENCOs. Thus, computer testing on a four-GENCO model is conducted to demonstrate the effectiveness of the proposed method and the applicability of the solution scheme to large-scale maintenance scheduling coordination problems.

An Analysis on the Maintenance Effect of the HVAC System with On-line Management Method (공조설비의 온라인 유지관리 효과 분석)

  • Kim, Yong-Ki;Lee, Tae-Won;Kang, Sung-Ju;Woo, Nam-Sub
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.54-59
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    • 2008
  • The poor maintenance and management of HVAC systems finally lead to the shortening of the life expectancy and result in the increase of operating costs and energy consumptions due to low efficiencies. Also, it is essential to try to develop ways to adequately maintain and to use the building facilities efficiently in order to preserve earth environment and the limited resource. In this study, an analysis on the maintenance and management cost for HVAC systems was carried out with the capacity of equipment. Besides, the LCC(Life Cycle Cost) based analysis was carried out to verify the effect of the doing maintenance and management. As the results, the case of the good maintenance and management is able to save LCC to 11 % than the case of the poor method.

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A Study on the Significance of Unit Capacity Factor (Utilization Rate) of Nuclear Power Plants and Measures for Increasing (원전 이용률의 의의 및 증진방안 고찰)

  • Don Kug Lee;Chi Bum Bahn
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.18 no.2
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    • pp.87-100
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    • 2022
  • Unit capacity factor (utilization rate) of nuclear power plants (NPPs) is an important performance indicator. Since the first commercial operation of Kori Unit 1 began in April 1978, the utilization rate of domestic NPPs has gradually increased, reaching 90% from the end of the 1990s. However, due to various issues such as the Fukushima accident in 2011, corrosion of the CLP, the utilization rate dropped to 65~80%. In the early 1980s, the utilization rate of the U.S. NPPs was around 60%. However, since 2004, it has been consistently maintained above 90%. Therefore, in this study, we first examined the causes of declining the utilization rate in domestic NPPs. Next, the significances of the utilization rates are reviewed in five aspects: investment capability, electricity rate, safety and export, etc., with discussion on the current status of the utilization rates in the U.S. Based on this, three key factors are derived as the reasons of the increasing: equipment reliability program, on-line maintenance and the pursuit of institutional rationality. And finally, by synthesizing above results, the measures for increasing the utilization rate of domestic NPPs are proposed in terms of equipment management, institutional improvements, and personnel resources.