• Title/Summary/Keyword: anchors

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Current Concepts in Arthroscopic Treatment of Anterior Shoulder Instability (견관절 전방 불안정에 대한 관절경적 최신 치료 경향)

  • Seo, Jae-Sung
    • Journal of Yeungnam Medical Science
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    • v.20 no.1
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    • pp.13-27
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    • 2003
  • In the past, the report of shoulder instability undergoing open shoulder stabilization had satisfactory outcomes of greater than 90%. However, the functional loss of open procedure is severe in abduction and external rotation especially. Current arthroscopic techniques for shoulder instability result in success rate equal to open surgical procedure when the labrum is properly fixed to the glenoid rim using suture anchors, the capsule is tightened, and associated bony and soft tissue pathology is addressed. The arthroscopic surgery facilitates the view within shoulder joint for more accurate diagnosis, reduces operating time, minimises postoperative pain, reduces operative morbidity, improves shoulder function, and provides the possibility to perform other procedure simultaneously. However, to accomplish a successful arthroscopic stabilization procedure and to prevent complications, numerous advanced arthroscopic skill must be mastered. Although the arthroscope provides means to visualize new lesions, the pathomechanism and biomechanical explanation is not clear yet. Further studies are necessary to develop for shoulder reconstruction.

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Joint installation of ceiling facilities in the subway system (지하철 천장시설물 공동설치 방안)

  • Lee, Pil-Sin
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1953-1959
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    • 2011
  • Subway stations have a characteristic that the facilities in the ceiling should be checked, replaced and expanded frequently. The new installation of supports (steel anchors) for new facilities and workers moving-around in the ceiling result in the damage in the ceiling finish material and concrete structure which also result in construction cost increase. In addition, the noise, vibration and dust generated during the work harm the station environment. There are civil complaints on these which give difficulty to ceiling works. Accordingly, this study suggests a ceiling frame construction method that considers the convenience, economy and efficiency of ceiling work by improving the support installation method for facilities in ceiling.

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Structural Analysis of Arch Anchor Brackets in Ground Anchor Construction (그라운드 앵커공법용 아치형 앵커브라켓의 구조해석)

  • Kim, Jae-Yeol;Kim, Young-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.14 no.1
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    • pp.69-76
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    • 2014
  • When we excavate an underground to build basement, the ground anchors are needed to prevent collapse of neighboring ground, subsidence and movement. Ground anchor construction required shore sheet piles, wales and struts as to maintain secure excavation. Existing box-type bracket using head part of ground anchor can not be possibly adjustable to the boring angle because the brackets are manufactured with unified angle in a factory. Also, box-type brackets have imperfection and instability caused by inequable force. In this study, a new bracket system is proposed. The bracket's side plate is reinforced and the angle of boring can be controlled. To investigate the structural performance of presented brackets, FEM analysis has been performed by using ANSYS commercial program. As a result, this bracket shows sufficient stability for all angle case and the strength is increased about 24% than existing bracket.

Ultimate Uplift Capacity of Permanent Anchor Embedded in Weathered Rock (풍화암에 근입된 영구 앵커의 극한인발력)

  • Yoo, Nam-Jae;Park, Byung-Soo;Jeong, Gil-Soo;Kim, Jin-Hwang
    • Journal of Industrial Technology
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    • v.21 no.B
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    • pp.195-203
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    • 2001
  • The purpose of this study is to estimate ultimate uplift capacity of permanent anchor which was cast into weathered rock. The ultimate uplift capacity was estimated from the load-displacement curve of four different anchors which have different bond length. The creep test was performed for 15minutes under the maximum load of each step in order to understand the load-transfer property of permanent anchor and to decide which anchor to choose. The destruction range of soil due to the changes in load was estimated by installing dial gauge on the ground which was cast into the weathered rock. Ultimately, the study on the behavior of the anchor case into the weathered rock was performed by comparing and analyzing the estimated result of the UUC obtained by the full scale pull out test in the field with the exsting theoretical and practical results of soil and rock anchor.

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Design Method and Evaluation of the Applicability of the Complex AAM Permanent Anchor (복합 AAM 영구 앵커의 설계법 및 적용성 평가)

  • Lee, Hyuk-Jin;Jung, Dae-Hoon;Kim, Jin-Hong;Lee, Chong-Ha;Kim, Hong-Taek
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.538-541
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    • 2007
  • In this study, the complex AAM permanent anchor was introduced and the design method for the complex AAM permanent anchor was showed by examining the relationship of the forces applied to the anchor, the ground failure, the loads inducing the tensile failure between the anchors, etc. In order to understand the behavioral characteristics of the complex AAM permanent anchor, the field pullout test was carried out, and the results obtained with the design method were compared with those of the field pullout test.

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A Study on Reinforcement Effect of Face Wall with Opening using Spiral Anchor (나선형철물을 사용한 치장벽체 개구부 보강 효과에 관한 연구)

  • Jung, Won-Chul;Hwang, Wan-Seon;Kwon, Ki-Hyuk
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.37-40
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    • 2007
  • Although masonry buildings fell into disfavour in the 1990's because of factors such ac bricklayers' high labor costs, bad reputation of poorly constructed masonry, masonry face wall is still preferred in korea as well as in other countries for its decorative value. Recently may problems with masonry face wall with opening have been reported, including cracks, deflection, swelling and even wall collapse in old masonry buildings, that mainly induced from the corrosion of connecting materials. So, it is necessary to develop the effective and uncorrosion connector. Therefore, this study aims to investigate the structural performance of masonry face walls with opening constructed by new connectors, spiral stainless anchors and to provide basic data for the field application of this method. The specimen reinforced bed joint has maximum load and displacement any other specimens.

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Fracture Behavior of CIP Anchor in Cracked Concrete (균열 콘크리트 면에서의 CIP앵커의 파괴거동)

  • 김호섭;윤영수;윤영수;박성균
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.169-174
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    • 2001
  • This study concerns crack effect on concrete anchor system and prediction of tensile capacity, as governed by concrete cone failure, of single anchors located at center of concrete specimen. To Investigate crack effect three different types of crack such as crack width of 0.2mm and 0.5nm, crack depth of loom and 20cm, and crack location of center and biased point were simulated. The static tensile load was subjected to 7/8 in. CIP anchor embedded in concrete of strength 280kg/$cm^{2}$. Tested pullout capacity was compared to prediction value by each current design method (such as ACI 349-97, ACI 349 revision and CEB-FIP which is based on CC Method), In these comparison CC Method and ACI revision showed almost same value in uncracked concrete specimen, however in cracked concrete CC Method showed conservativeness. Therefore the design by ACI 349 revision is recommended for the safe and economic design.

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Preliminary Study on the Behavior of Rock Anchors Subjected to Repeated Loadings (반복하중을 받는 락앵커의 거동에 대한 기초적 연구)

  • 원상연;조남준;황성일
    • Journal of the Korean Geotechnical Society
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    • v.17 no.1
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    • pp.25-34
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    • 2001
  • 송전철탑의 기초로써 락앵커는 바람에 의해 반복적인 하중을 받고 있다. 반복하중은 락앵커의 인발 지지력 감소와 누적변위의 증가를 유발할 수 있다. 그러므로 송전철탑의 락앵커 설계시 세심한 주의가 요구된다. 본 논문에서는 세 가지 암반형태에 시공된 모형 락앵커에 대하여 반복하중 시험을 수행한 결과들을 제시하였다. 시험결과에 의하면 정적 극한하중의 50%보다 작은 최대 반복하중(Q$_{max}$)이 락앵커에 작용할 경우, 락앵커의 지지력에 대하여 반복하중의 영향이 없다. 최대 반복하중이 정적 극한하중의 50%에서 75%로 작용할 경우 누적변위의 증가를 유발하고, 정적 극한하중의 75%이상인 경우 락앵커의 지지력에 심각한 영향을 미친다. 따라서 정적 극한하중의 50% 이상의 반복하중을 받는 락앵커는 불안정하다.

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A Study of the Anchorage loss of Ground Anchor Using Spacing Apparatus and Spring (간격유치장치를 이용한 어스앵커 인장에 관한 연구)

  • Jeong, Sang-Min;Park, Young-Keun;Park, Moo-Kon;Kim, Kwang-Eok;Lee, Keun-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.4 s.18
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    • pp.139-144
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    • 2005
  • A ground anchor system is used as a load carrying element in soil work. The conventional systems with ground anthers bring about the anchorage loss of wedges when anchors are installed for the support of soil structures. Hence we developed the new type of anchor system using both the spacing apparatus and spring (length 60mm, diameter 6mm). In this system, we tan directly check the condition of wedges and PS strands and modify the problems with the slip and anchorage of wedges under construction. For demonstrating the superiority of this system, we carried out a series of the laboratory test. Consequently, we can obtain satisfactory result (18.99$\%$ reduction to the loss of conventional systems). Moreover, the replacement of wedges is easy and simple when retensioning of strands.

Seismic Design Guidelines for Welded Steel Oil Storge Tank (KS B 6225) (강제석유저장탱크(KS B 6225)의 내진설계기준 개선 안)

  • Park, Jong-Ryul;O, Taek-Yeol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.3
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    • pp.544-552
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    • 2002
  • Recommended seismic design guide for the flat bottom vortical-cylindrical oil storage tanks in KS B 6225 is presented. Under earthquake excitations, the hydrodynamic pressure exerted on the tank walls produces overturning moment which may cause either a failure of the anchors or a buckling of the tank shell near its base. The basis for establishing design loads due to hydrodynamic pressure is described including seismic zone risk map in Korea, zone coefficients and the essential facilities factor. This procedure for calculating applied compressive stress on the shell base subjecting to seismic load and for estimating the allowable buckling stress is described.