• Title/Summary/Keyword: Reinforcing

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Development of FRP Recycling Process for Regenerating Applications of Fire Resistance Performance of High Strength Concrete (고강도 콘크리트의 내화성능 용도에 따른 FRP재활용 공정 개발)

  • Lee, Seung Hee;Park, Jong Won;Yoon, Koo Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.18 no.3
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    • pp.207-215
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    • 2015
  • In the last decade, increasing national research fund for recycling the waste FRP (fiber reinforced plastics) ships which has caused environmental problems, improves the technology making concrete-reinforcing fibers out of the waste FRP. Furthermore, the concrete with recycled FRP fiber was tested for the structural performance. Experimental strength tests show that use of recycled FRP powder does not reduce the compressive strength of high strength concrete, and does increase the fire resistance performance of high strength concrete significantly. But, the study in investigating the properties of recycled fiber powder from waste FRP has not been completed because of the absence of the method of separation of mat layer from the waste FRP. This study is to propose a new extracting method of the mat layer from waste FRP, which is the efficient and environment friendly system. and thus it is considered to be the useful recycling method for fire resistance high concrete products or structures.

Oriental and Western Consideration of Habitual Abortion (습관성(習慣性) 유산(流産)의 동서의학적(東西醫學的) 고찰(考察))

  • Baek, Seung-Hee;Song, Byung-Kee;Lee, Kyung-Sub
    • The Journal of Korean Medicine
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    • v.16 no.2 s.30
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    • pp.115-133
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    • 1995
  • In the Oriental Western Consideration of Habitual Abortion, the result of this study is summarized as follows: 1. Habitual abortion means repetition of Tatae(abortion within 3 months), Sosan(abortion after 3 months), and Bansan(abortion after 5 months), as it agrees with Hoaltae, Sutatae and Nuing-Nuta in oriental medical science. 2. Frequency in Occurrence of habitual abortion is about 0.2-0.4%> in the whole pregnancy and the Ratio of Risk increases according to frequency and age increase. 3. Generally, the cause of habitual abortion is due to the cause of the mother. Therefore, diagnosis and treatment of before-childbirth are needed, and 'measures taken to prevent abortion' is in use to improve the condition of health of before-childbirth in oriental medical science. 4. The 50-60% of early abortion is due to the heterochromosome and the ratio of risk of habirual abortion is hightest in heterochromosome. 5. The causes of habitual abortion are summarized as vital energe and blood weakness. impairment of Chong and Ren, aflection by exopathogen, fever caused by blood deficiency. weakness of the spleen and the stomach, excess of seven emotion. excess of a sexual desire and injury of a contusion and also the treatments are summarized as invigorating qi (vital energy) and enriching the blood, reducing fever and enriching the blood, reinforcing the spleen, tonifying the Chong and Ren, the practice of a sceticism, psychological peace in oriental medical science. 6. The approch of modem oriental medical science is based on diagnosis and treatment based on 'over all analysis of symptoms and signs' of traditional oriental medical science. it goes abreast with diagnosis of western medical science, and it can be expected mare inclusive effect of treatment because 'Acupuncture for prevent abortion', 'Acupuncture with the needle warmed by burning moxa', and so on being developed except medicinal therapy.

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Analysis for Mechanical Behavior of GFRP Rock Bolt for Permanent Support of Tunnel (영구 터널지보재로서의 활용을 위한 GFRP 록볼트의 역학적 거동 분석)

  • Sim, Jong-Sung;Kang, Tae-Sung;Lee, Yong-Taek;Kim, Hyun-Joong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.6
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    • pp.124-131
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    • 2010
  • Rock Bolt generally utilizes deformed reinforcing bar welded from structural steel of which strength is higher than required for making advantageous use of the support function of ground. In the condition with highly corrosive underground water, however, problem frequently occurs on tunnel and slope stabilization in terms of repair, rehabilitation and maintenance issues due to the destruction of Rock Bolt by corrosion of steel. A structural performance evaluation for GFRP Rock Bolt was conducted for the purpose of resolving the foregoing problem and at the same time developing a permanently-usable support material. This study intended to evaluate the safety factor of GFRP Rock Bolt by implementing the slope stability interpretation via structural analysis on the basis of its structural characteristics derived from both tensile force function test and shear force function test. It is judged based on the results that GFRP Rock Bolt would secure sufficient ground stability as an alternative material for existing Steel Rock Bolt.

A Study on Constructability Improvement of LB-DECK Panel (LB-DECK 패널의 시공성 향상에 관한 연구)

  • Cho, Hyun-Chul;Lho, Byeong-Cheol;Cho, Gyu-Dae;Choi, Kyu-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.2 s.54
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    • pp.122-128
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    • 2009
  • This study is to improve constructability of LB-DECK construction in site such as inconvenience of main and distribution bars in arrangements LB-DECK Panel which is work is applied to many bridges these days as a permanent formwork. So, the constructability is improved by changing the method of allocation of main reinforcing bar and distribution bar which is reviewed for improving efficiency of design and construction process among the suggested methods. The crack shapes, deflections, and strains under static load of the improvement of LB-DECK Panel are compared and analyzed to former LB-DECK Panel. As a result, 13% of strength compared to before the improvement of LB-DECK Panel, and 10% of strength is increased in the case of slab.

An Estimation of Shear Capacity of Hexagonal Masonry Walls Under Cyclic Loading (반복하중을 받는 육각형 블록 벽체 전단내력평가)

  • Chang, Gug-Kwan;Seo, Dae-Won;Han, Tae-Kyoung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.6
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    • pp.205-214
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    • 2010
  • Masonry structures have been used throughout the world for the construction of residential buildings. However, from a structural point of view, the masonry material is characterized by a very low tensile strength. Moreover, the bearing and shear capacity of masonry walls have been found to be vulnerable to earthquakes. In this study, to improve the seismic performance of masonry walls, hexagonal blocks were developed and six masonry walls made with hexagonal block were tested to failure under reversed cyclic lateral loading. This paper focuses on an experimental investigation of different types of wall with hexagonal blocks, i.e. walls with different hexagonal blocks and with different reinforcing bar arrangements, subjected to applied cyclic loads. The cracking, damage patterns and hysteretic feature were evaluated. Results from the hexagonal masonry wall were shown more damage reduction and less brittle failure in comparison to the existing rectangular masonry walls.

A Study on the Structural Behavior of LB-DECK Panel Considering Rebar-Arrangement in Site (현장 배근이 LB-DECK 패널의 구조거동에 미치는 영향)

  • Lho, Byeong-Cheol;Cho, Gyu-Dae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.3
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    • pp.167-174
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    • 2008
  • The objective of this study is to verify whether the composite action is sufficiently strong to withstand at the interface and the structural behavior of LB-DECK panel with field concrete slab strengthened with main reinforcing bars. Static and fatigue tests are performed for LB-DECK panels with varied shapes and amounts of rebars, and the results are compared with those of field concrete panel(FCP). The test results indicate that the LB-DECK panel with 1.5 times of more rebars inside significantly increase the overall stiffness. LB-DECK penel usually shows on average 52.1 percent of improved stiffness compared with the FCP. The fatigue test results also show that the LB-DECK panel can withstand two-million cycles of repeated loads without any damage.

An analytical Study on the Influence length of SCP Method (측방이동 대책공법(SCP)의 영향범위 산정에 관한 해석적 연구)

  • Lee, Young-Keun;Park, Chun-Sik;Kim, Jong-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09b
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    • pp.152-160
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    • 2010
  • In this study, cohesion of soft ground, soft ground depth and embankment height varying conditions, such as the impact of each condition after the calculation of the range, SCP was performed to evaluate the applicability of the method. Reinforcing effects of scope, and permit lateral movement of SCP 2D and 3D analysis of the program were calculated by the displacement ratio, the result follows. The height and depth of soft soil embankment with increasing and decreasing the cohesion tends to be affected were long range, SCP method applied by the finite element analysis Cu = 1.0tf/$m^2$, embankment height is 3.0m depth of soft soil can be applied in a less than 5.0m, and Cu = 3.0tf/$m^2$, embankment height, the soft soil depth is 3.0m 12.0m, Cu = 3.0tf/$m^2$, embankment height is 5.0m less than 7.0m depth of soft soil can be applied in was. And Cu = 5.0tf/$m^2$, embankment height is 3.0m below 15.0m depth rouge anti Floor, Cu = 3.0tf/$m^2$, embankment height of 5.0m 12.0m depth below the soft soil, Cu = 5.0tf/$m^2$, If the depth of soft soil embankment height of 7.0m and below 5.0m was applicable.

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Using the PAPM to Examine Factors Associated with Stages of Adoption for Stomach Cancer Screening (위암검진행태 단계의 관련요인 : PAPM을 적용하여)

  • Kye, Su-Yeon;Choi, Kui-Son;Sung, Na-Young;Kwak, Min-Son;Park, Su-Ho;Bang, Jin-Young;Park, So-Mi;Hahm, Myung-Il;Park, Eun-Cheol
    • Korean Journal of Health Education and Promotion
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    • v.23 no.4
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    • pp.29-45
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    • 2006
  • Objectives: The aim of this study was to determine the distribution of stages of adoption in stomach cancer screening and elucidate differences among stages. Methods: A randomly selected sample of 712 Korean males and females aged 40 years or over were interviewed. Stomach cancer screening intention and behavior, sociodemographic characteristics, beliefs, self-efficacy and reinforcing characteristics were assessed. Results: The majority of participants were not on-schedule screening(unaware 3.2%, unengaged 20.8%, deciding about acting 24.0%, decided not to act 9.6%, decided to act 14.5%, acting 9.7%, maintenance 18.3%). Perceived susceptibility, perceived barriers, self-efficacy, other cancer screening experiences were significantly associated with higher compared to lower Precaution Adoption Process Model(PAPM) stages. Conclusions: This study appears to be applicable of the Precaution Adoption Process Model to understanding stomach cancer screening behavior. Our results suggest that it is needed to develop the tailored message for adherence of stomach cancer screening.

Laboratory Model Tests on the Load Transfer in Geosynthetic-Reinforced and Pile-Supported Embankment System (토목섬유보강 성토지지말뚝시스템에서의 하중전이 효과에 관한 모형실험)

  • Hong, Won-Pyo;Lee, Jae-Ho
    • Journal of the Korean Geosynthetics Society
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    • v.9 no.3
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    • pp.9-18
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    • 2010
  • A series of model tests were performed to investigate the load transfer by soil arching in geosynthetic-reinforced and pile-supported(GRPS) embankment systems. In the model tests, model piles with isolated cap were inserted in the model container and geosynthetics was laid on the pile caps below sand fills. The settlement of soft ground was simulated by rubber form. The loads acting on pile caps and the tensile strain of geosynthetics were monitored by data logging system. At the given interval ratio of pile caps, the efficiency in GRPS embankment systems increased with increasing the height of embankment fills, then gradually converged at constant value. Also, at the given height of embankment fills, the efficiency decreased with increasing the pile spacing. The embankment loads transferred on pile cap by soil arching increased when the geosynthetics installed with piles. This illustrated that reinforcing with the geosynthetics have a good effect to restraint the movement of surrounding soft grounds. The load transfer in GRPS embankment systems was affected by the interval ratio, height of fills, properties of grounds and tensile stiffness and so on.

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A Study on the Design Method of the Reinforced Earth Structures Considering Compaction Induced Stresses (다짐 유발응력을 고려한 보강토 설계방법에 관한 연구)

  • 임철웅;백영식
    • Geotechnical Engineering
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    • v.8 no.4
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    • pp.5-16
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    • 1992
  • The main purpose of this the sutdy is to develop the reinforced earth structure design method considering induced stresses and deflections resulting from placement and compaction of soil. In this paper, the new reinforcement Geolog developed by the author is also introduced which is being used as one of the effective earth reinforcing structure against compaction induced stresses. This study adopted the Seed's bilinear model in the estimation of the com paction induced stresses and compute the peak lateral stresses during compaction by doubled Boussinessq's elastic solution of mirror image theory, thereafter, calculate the residual compaction induced lateral stresses from the above peak lateral stress by the residual fraction. It is considered to be reasonable that the compaction induced stresses be added to the lateral earth pressures estimated from conventional gravity analysis considering the actual stresses during service life of the structures. "GEOLOG", a composite of steel bar and attached concrete stopper is found to be effective against tension and pull - out failure. In this paper, the design method considering the compaction induced stresses and the effect of Geolog reinforcement is suggested for the remforced earth structures where backkfill settlement on displacements are not allowed as in the cases of the bridge abutments or double faced reinforcement earth structures.tructures.

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