• Title/Summary/Keyword: Reinforcing

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Comparative Analysis of On-site Construction Management in Korea and Japan (건설현장 관리기술에 대한 한·일간 비교분석 예비연구)

  • Song, Sang-Hoon;Sohn, Jeon-Grak
    • Journal of the Korea Institute of Building Construction
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    • v.10 no.6
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    • pp.27-38
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    • 2010
  • Considering the similarity in legislation and long-term industrial trend of Korea and Japan, continuous attention to the Japanese situation is useful for the development of a domestic construction strategy. In order to compare the current on-site construction management practice of the two countries and analyze the reasons for discrepancy, a literature review, expert interview, and site investigation were executed. A detailed survey of experts with experience in both countries revealed that overall, Korea's level of competitiveness is gaining on that of Japan. However, the Japanese construction industry was still evaluated as maintaining higher competitiveness, due mainly to comprehensive planning for operation, well-established design documents, and effective total quality safety environment management, all of which are combined with institutional support and a cooperative attitude by labor. Adjustments should be made for advanced technologies considering the attributes of a typical Japanese construction prior to establishing and implementing application strategies according to the suggestion of experts. Based on the results of this study, a benchmarking of Japanese strength should be conducted, and this is eventually expected to contribute to establishing green construction, enhancing safety, improving culture, and reinforcing the capabilities of participants.

Experimental Study on Dry Waterproofing Technology Using Synthetic Polymer Sheet Comprised of Synthetic Resin Metal Sheets and Tri-Layered Filler (합성수지 메탈시트와 3면겹침용 채움재가 공법화된 합성고분자계 시트를 이용한 건식화 방수기술에 대한 실험적 연구)

  • Koo, Ja-Ung;Kim, Bum-Soo;Lee, Jung-Hun;Song, Je-Young;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.11a
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    • pp.139-140
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    • 2017
  • This technology employs a method of forming a single-ply PLUS waterproofing sheet layer comprised of applying a single-ply synthetic polymer layer on a vibrating structure (steel frame, RC) or an inclined surface by using a T joint lap-filling coil and an embedded metal coated sheet. The T - joint reinforcing lap-filling coil was used to block the ingress channel of the rainwater by applying the material in the vulnerable area where the three sides of the waterproof sheet overlapped. Conventional waterproofing techniques have a problem in that the waterproof sheet is pierced because the end portion of the waterproof sheet applied to the vertical portion is fixed by a nail, and the sealant applied to the end portion of the sheet cannot easily secure long-term waterproof durability due to the influence of the external environment. Therefore, the developed technology secured the waterproof durability against the vertical part by using the embedded metal sheet. In addition, automatic hot-air fusing is used to improve the quality of waterproof construction and point fixation method using fixed hardware. This is a technology that is not significantly restricted in the high degradation level regions of domestic waterproof construction environments in Korea such as low-temperature environment, wet floor.

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Corrosion Protection of Rebars Using High Durability Polymer Cementitious Materials for Environmental Load Reduction (환경부하저감형 고내구성 폴리머 시멘트계 재료를 이용한 철근 부식저감기술)

  • Kim, Wan-Ki;Chung, Seung-Jin
    • KIEAE Journal
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    • v.10 no.5
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    • pp.131-137
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    • 2010
  • The building industry must aim at high-durability and sustainability. A holistic life cycle based approach is recommended to reduce the environmental load. In recent years, technical innovations in the construction industry have advanced to a great extent, and caused the active research and development of high-performance and multifunctional construction materials. Nowadays, various polymer powders have been commercialized to manufacture construction materials in the form of prepackaged-type products, which have rapidly been developed for lack of skilled workmen in construction sites. Recently, terpolymer powders of improved quality have been developed and commercialized as cement modifiers. And, hydrocalumite is a material that can adsorb the chloride ions (Cl-) causing the corrosion of reinforcing bars and liberate the nitrite ions (NO2-) inhibiting the corrosion in reinforced concrete, and can provide a self-corrosion inhibition function to the reinforced concrete. The purpose of this study is to ascertain the self-corrosion inhibition function of polymer-modified mortars using redispersible powders with hydrocalumite. Polymer-modified mortars using VA/E/MMA and VAE redispersible powders are prepared with various calumite contents and polymer-binder ratios, and tested for chloride ion penetration depth, corrosion inhibition. As a result, regardless of the polymer-binder ratio, the replacement of ordinary portland cement with hydrocalumite has a marked effect on the corrosion-inhibiting property of the polymer-modified mortars. Anti-corrosion effect of polymer-modified mortars using VA/E/MMA terpolymer powder with hydrocalumite is higher than that of VAE copolymer powder.

Properties of Self-hardened Inorganic Coating in the System Alumina-Silica-Calcium Oxide by the Reaction with Alkalies (알칼리 반응에 의한 알루미나-실리카-산화칼슘계 무기질 자기경화 코팅의 특성)

  • Jeon, Chang-Seob;Song, Tea-Woong
    • Journal of the Korean Ceramic Society
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    • v.47 no.5
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    • pp.381-386
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    • 2010
  • Some basic properties of inorganic coatings hardened by the room temperature reaction with alkalies were examined. The coating paste was prepared from the powders in the system $Al_2O_3-SiO_2$-CaO using blast furnace slag, fly ash and amorphous ceramic fiber after mixing with a solution of sodium hydroxide and water glass. The mineralogical and morphological examinations were performed for the coatings prepared at room temperature and after heating to $1200^{\circ}C$ respectively. The binding force of the coating hardened at room temperature was caused by the formation of fairly dense matrix mainly composed of oyelite-containing amorphous phase formed by the reaction between blast furnace slag and alkali solution. At the temperature, fly ash and ceramic fiber was not reacted but imbedded in the binding phase, giving the fluidity to the paste and reinforcing the coating respectively. During heating up to $1200^{\circ}C$, instead of a break in the coating, anorthite and gehlenite was crystallized out by the reaction among the binding phase and unreacted components in ternary system. The crystallization of these minerals revealed to be a reason that the coating maintains dense morphology after heating. The maintenance of binding force after heat treatment is seemed to be also caused by the formation of welldispersed fiber-like mineral phase which is originated from the shape of the amorphous ceramic fiber used as a raw materials.

A Study on the Design Policy Reinforcing Korea's design Competitiveness - Focusing on Clusters System in Italia (우리나라의 디자인 경쟁력 강화를 위한 디자인정책 연구 - 이탈리아의 Clusters System을 중심으로)

  • 천정임;변추석
    • Archives of design research
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    • v.15 no.3
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    • pp.191-200
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    • 2002
  • In the 1980s, even though Italy faced economic depression, Italy (she), now, internationally became a strong nation with its best design by national unity and the developmental leap of industry through design. In Italy, especially, small and medium enterprises are accumulated by the same business in each area on the structure of a Cluster system. Italy has some characteristics that being the Italians' elastic way of management, family management and development of a consortium of small and medium enterprises, which have flexibility, imagination and decisiveness. We have to bring these intensified factors of design competitiveness to our country so that we should form the union in order to have a monopoly of specific enterprises based on the specialized technology of small and medium enterprises innovating the structure of a small quantity production having developmental flexibility. We also heighten the sense of designer and publics by achieving social opinion and cult! ural revival. Moreover, the mind of managers has to be changed more aggressively. Finally, the actual policy of design will be established and peformed, and design-company (enterprises) and the industrial economy will generally develop when we activate the structure of the industry centered on small and medium enterprises and design-related association that is united and participates in the establishment of design policy.

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A Study on the Soundproofing Plate Techniques for Noise Reduction of Power Transformers (전력용 변압기 소음저감을 위한 차음판 기술에 관한 연구)

  • Kweon, Dong-Jin;Koo, Kyo-Sun;Kim, Jung-Chon;Kim, Jin
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.12
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    • pp.47-55
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    • 2008
  • According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint has been increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an enclosure to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation from the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. To shut out sound emitted from transformers, we developed a soundproof technology that wall up reinforcing bar by steel sheet. For the practical application of it, we analyzed the vibration characteristics of a transformer tank and reduction of noise according to soundproof plate. As a result, it is confirmed that the technology can reduce 11 [dB] of transformer noise.

Factors influencing the attitude toward death in college nursing student (간호대학생의 죽음태도 및 영향요인)

  • Kim, Jong Gun;Oh, Su Min;Cheon, Eui Young;Yoo, Jang Hak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.1
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    • pp.676-683
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    • 2016
  • This study examined the relationships between self-esteem, and the awareness of biomedical ethics and the quality of life and death attitude, as well as the factors influencing the death attitude among 130 nursing students in college. The data were analyzed using an independent t-test, one-way ANOVA, Pearson correlation coefficients, and multiple regression with the SPSS Win 14.0 Program. Significant positive correlations were observed between the self-esteem and death attitude, between the awareness of biomedical ethics and the death attitude. The predictors for the death attitude were self-esteem (${\beta}=.25$) and awareness of biomedical ethics (${\beta}=.11$). The model explained 21.2% (F=10.4, p<.001) of the variance. The findings indicated that more study will be needed to explore the factors influencing the death attitude and to develop education programs for reinforcing a positive death attitude among college nursing students.

Structural Performance Evaluation of Prestressed Concrete Trapezoidal Girders Using Socket Joint System (소켓연결 방식을 이용한 프리스트레스트 콘크리트 제형 거더의 구조성능 평가)

  • Shim, Won-Bo;Min, Kyung-Hwan;Choi, Hong-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7244-7249
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    • 2015
  • In this study, in order to asses the structural performance of trapezoidal PSC girder using a socket joint system and it is possible to calculate the optimized cross-section of the web element tests were carried out for each specimens. we conducted a socket joint performance test, web bending and shear performance tests and all tests were performed at 4 point loading method. The initial crack load of socket joint specimen was significantly lower than the reference specimen but post peak behavior was no significant differences. And the length of the loop joint of the reinforcing bars had no significant effect on the maximum load. As a web shear tests, to obtain a maximum load of the specimen has a prestressing rod reinforced at tension side. As a web flexural tests, to obtain higher diagonal cracking load in specimen of reinforced using prestressing rod than reference specimen.

Analytical Study for Optimal Reinforcement Amount and Development of FRP Seismic Reinforcement that can be Emergency Construction (긴급시공이 가능한 FRP 내진보강재 개발 및 최적 보강량 산정을 위한 해석적 연구)

  • Kim, Jin-Sup;Kwon, Min-Ho;Seo, Hyun-Su;Lim, Jeong-Hee;Kim, Dong-Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.5
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    • pp.136-145
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    • 2013
  • Social interest in the seismic retrofit of the structure is growing massive earthquake that occurred recently. The brittle fracture of Non-seismically designed Columns lead to full collapse of the building. In the past, cross-sectional expansion method, a steel plate reinforcing method is applied mainly in recent years, fiber-reinforced method utilizing the advantages of the composite material are preferred. However, the reinforcement methods such as this, there is a drawback to induce physical damage to structures, and time consuming work space is large. IIn this study, FRP seismic reinforcement was developed using the Aluminum connector and the composite material (Glass Fiber Reinforced Polymer). Then, the optimum quantities of FRP seismic reinforcement was determined using a nonlinear finite element analysis program. Finally, the quantity decision process through the design and analysis of FRP reinforcement was suggested.

The Structural Reinforcing of PCC-Deck with Cantilever (캔틸레버를 갖는 PCC-Deck의 구조보강)

  • Lho, Byeong-Cheol;Kim, Chang-Kyo;Park, Jong-Hyeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.5
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    • pp.21-30
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    • 2013
  • LB-Deck is one of the widely used member in interior part of girders as a permanent formwork in structures, but it is not easy to apply to the exterior part of girder due to the overturning and excessive deflection. Considering allowable deflection and safety of the exterior part, Precast Concrete Cantilever Deck (PCC-Deck) is proposed with normal LB-Deck in inner part and extended bars of LB-Deck in outer part. Both numerical analyses and experimental tests were compared to check the safety and allowable deflection for 6 types of PCC-Deck, and D-type (with 16 mm top bar, 6 mm lattice bar, 12 mm bottom bar) is suggested as an optimal structural reinforcement to the 28 kN of maximum load and 27.49 mm of final deflection. The load resisting ratio of D-type under working load of 10 kN was about 2.8 times and 77.5% of improvement was observed.