• Title/Summary/Keyword: RC work

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Structural Analysis Methods for RC Building Demolition Work under Heavy Equipment Loading (해체공사 실무자를 위한 기계식 해체대상 RC구조물의 해석기법 제안)

  • Park, Seong-Sik;Lee, Bum-Sik;Park, Ji-Young;Kim, Hyo-Jin;Sohn, Chang-Hak
    • Land and Housing Review
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    • v.2 no.4
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    • pp.569-575
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    • 2011
  • In domestic mechanical demolition work against RC building, unsuitable selection and loading of heavy equipment have led to occasional accidents such as collapse of structural members during the work. Therefore, proper analysis technique to easily decide allowable equipment load on the structure is needed at the planning stage of mechanical demolition work. In this paper, performing loading test and elastic analysis against 4-story building at full scale, we confirm appropriateness for allowable load of equipment on RC structures, which was suggested in previous study, and suggest structural analysis method that can evaluate safety of RC building during the mechanical demolition. The suggested method can be effectively utilized to improve work efficiency through safety of mechanical demolition work against RC building and proper management of equipments.

Work and Life Balance in teleworking Environment - Application of CLD, TP, and TRIZ - (원격근무환경에서 일과 삶의 균형방안: 인과지도, 사고프로세스와 트리즈의 적용)

  • Kang, Jae-Jung
    • The Journal of Information Systems
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    • v.29 no.3
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    • pp.179-195
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    • 2020
  • Purpose & Design/methodology/approach Amidst the COVID-19 spread, interest in telework has been increasing as a way to respond to environmental changes and improve organizational performance. In this study, causal loop diagram, thinking process, and four principles of TRIZ were used to find various ways to achieve work-life balance for workers and firms in teleworking environment. Findings The result of the causal loop diagram shows that keeping work-life balance is needed to provide free extra time for workers and achieve the firm's performance through efficient coordination between departments in teleworking environment. Using thinking process of TOC, we proposed a evaporating cloud for work-life balance and reviewed assumptions and premises to maintain extra free time for workers and achieve firm's performance paradoxically, and suggested solutions through the breakdown of the assumptions and premises. Resolving the contradiction(RC) by spatial separation is to divide working spaces into home, smart center, and mobile work types, to find both ways to achieve the organizational performance, and to provide extra time for workers. RC by temporal separation is to divide working time into various unit time, and to find ways to achieve organizational performance through doing work at office or home periodically or shiftly according to a predetermined schedule and time setting. RC by situational separation is to give options of flexible methods of performing work according to the conditions of the company or the worker. RC by separation between part and a whole is to find ways to organize and do the work so that the entire work can be completed efficiently even if each work is performed separately in teleworking way. This study is meaningful in that it provides basic thinking framework for achieving work-life balance in teleworking environment and proposes ways to resolve conflict from various perspectives, but it is limited in that it has not been tested empirically.

Experimental Study on the Fatigue Enhancement of RC Beams with Glassfibers (유리섬유보강 RC보의 휨 및 전단 피로성능개선의 실험 연구)

  • 조창백;양정비;정영수;김기봉
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.507-512
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    • 1999
  • In recent years, glassfibers have been used for strengthening in RC structure because of low material cost and easy repairing work. The purpose of this study is to experimentally and analytically investigate the effect of glassfibers for enhancing the capacity of RC flexural beams and shear beams. The experimental result shows that yield and ultimate strength of RC flexural beam with glassfibers are increased by approxiamate 13% and 26%, comparing with those for without glassfibers, and also ultimate strength of RC shear beam with glassfibers are increased by 34%, comparing with those for without glassfibers.

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ON THE IDENTITIES OF BOL-MOUFANG TYPE

  • Solarin, A.R.T.
    • Kyungpook Mathematical Journal
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    • v.28 no.1
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    • pp.51-62
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    • 1988
  • In this work we study properties of five identities of Bol-Moufang type (1). We establish a necessary and sufficient condition for a loop to be an RC-loop. A corollary to this is the condition for a Bol loop to be an RC-loop. Some proerties of a generalization of RC-loops are discussed. We also state the relationship between the supernucleus M(G) of a loop G and the nucleii of loops which do not have the inverse property. Finally, we give two tables of non-associative RC-loops of order 16, which are not Bol loops.

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Mechanical properties of carbon fiber sheet and carbon fiber strand sheet based on carbon fibers for the reinforcement of highway bridge RC slabs (도로교 RC 상판 보강을 위한 탄소섬유 기초 carbon fiber sheet와 carbon fiber strand sheet의 역학특성)

  • Won, Chan Ho;Abe, Tadashi;Ahn, Tae-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.6
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    • pp.290-293
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    • 2015
  • Recently, a lot of interest has been shown in structural maintenance managements of civil infrastructures. Many researchers have been conducted on various maintenance techniques and repair materials. Among other fiber materials the carbon fiber materials are especially focused on maintenance management of Highway Bridges. Extensive work has been done on Carbon Fiber Sheet (CFS). Nevertheless, Carbon Fiber Strand Sheet (CFSS) is a newly developed material, on which limited work has been done until now. Therefore, in this study bonding the CFSS to RC slab specimen and fatigue resistance evaluation has been conducted. The results demonstrated an increase of 25.3 times more reinforcement of RC slab compared to non-reinforced RC slab. Moreover, compared to CFS-bonded RC slab, The CFSS-bonded RC slab showed 1.2 times greater reinforcement.

Seismic Analysis of Underground RC Structures considering Interface between Structure and Soil (경계면 요소를 고려한 지하 철근콘크리트 구조물의 지진해석)

  • 남상혁;변근주;송하원;박성민
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.87-92
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    • 2000
  • The real situation of an underground reinforced concrete(RC) structure with the surrounding soil medium subjected to seismic load is quite difficult to be simulated through an expensive work and, even if it is possible to arrange such an experiment, it will be too expensive. So development of analytical method can be applied usefully to seismic design and seismic retrofit through an analysis of seismic behavior and seismic performance evaluation. A path-dependent constitutive model for soil that can estimate the response of soil layer is indispensible for dealing with kinematic interaction of RC/soil entire system under seismic loads. And interface model which deals with the dynamic interaction of RC/soil entire system is also necessary. In this study, finite element analysis program that can consider path-dependent behavior of RC and soil, and interfacial behavior between RC and soil is developed for rational seismic analysis of RC/soil entire system. Using this program, nonlinear behavior of interface between RC and soil is analyzed, and the effect of interfacial behavior to entire system is investigated.

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Static Test on Aged RC Bridge Slabs Strengthened With TYFO Glassfibers (TYFO 유리섬유로 보강된 노후교량 상판에 대한 정적실험)

  • 송재필;김철우;김기봉;정영수;이광명
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.621-626
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    • 1997
  • Recently, TYFO glassfibers have been used for strengthening n aged RC bridge slabs because of low material cost and easy repairing work. The purpose of this study is to experimentally and analytically investigate the effect of TYFO glassfibers for enhancing the capacity of aged RC bridge slabs. Tes result shows that yield and ultimate strength of RC slabs with TYFO are increased as 11~18% and 25~35% comparing with those for RC slabs without TYFO, respectively, Also, ductility of RC slabs strengthened with TYFO have been significantly increased. Further tests have been performing on aged RC bridge slabs strengthened with carbon fiber strips.

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Static and Fatigue Test on RC Flexural Beam with Glassfibers (유리섬유로 보강괸 RC휨부재에 대한 정적 및 피로실험)

  • 손영준;윤진수;강보순;정영수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10b
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    • pp.851-856
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    • 1998
  • In recent years, glassfibers have been used for strengthening in RC structure because of low material cost and easy repairing work. The purpose of this study is to experimentally and analytically investigate the effect of glassfibers for enhancing the capacity of RC structure. The result shows that yield and ultimate strength of RC beam with glassfibers are increased by approximate 13% and 26%, comparing with those for RC beam without glassfibers. It has been observed from the test that fatigue behaviors of RC beam with glassfibers have been significantly and large improved comparing with those for RC beam without glassfibers.

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Modeling shear behavior of reinforced concrete beams strengthened with externally bonded CFRP sheets

  • Khan, Umais;Al-Osta, Mohammed A.;Ibrahim, A.
    • Structural Engineering and Mechanics
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    • v.61 no.1
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    • pp.125-142
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    • 2017
  • Extensive research work has been performed on shear strengthening of reinforced concrete (RC) beams retrofitted with externally bonded carbon fiber reinforced polymer (CFRP) in form of strips. However, most of this research work is experimental and very scarce studies are available on numerical modelling of such beams due to truly challenging nature of modelling concrete shear cracking and interfacial interaction between components of such beams. This paper presents an appropriate model for RC beam and to simulate its cracking without numerical computational difficulties, convergence and solution degradation problems. Modelling of steel and CFRP and their interfacial interaction with concrete are discussed. Finally, commercially available non-linear finite element software ABAQUS is used to validate the developed finite element model with key tests performed on full scale T-beams with and without CFRP retrofitting, taken from previous extensive research work. The modelling parameters for bonding behavior of CFRP with special anchors are also proposed. The results presented in this research work illustrate that appropriate modelling of bond behavior of all the three types of interfaces is important in order to correctly simulate the shear behavior of RC beams strengthened with CFRP.

Chloride Penetration in Circular Concrete Columns

  • Morga, M.;Marano, G.C.
    • International Journal of Concrete Structures and Materials
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    • v.9 no.2
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    • pp.173-183
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    • 2015
  • Most of the diffusion models of chloride ions in reinforced concrete (RC) elements proposed in literature are related to an isotropic homogeneous semi-infinite medium. This assumption reduces the mathematical complexity, but it is correct only for plane RC elements. This work proposes a comparison between the diffusion model of chloride ions in RC circular columns and in RC slab elements. The durability of RC cylindric elements estimated with the circular model instead of the plane model is shown to be shorter. Finally, a guideline is formulated to properly use the standard and more simple plane model instead of the circular one to estimate the time to corrosion initiation of cylindrical RC elements.