• Title/Summary/Keyword: anchor force

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A Method of SMART Anchor for a Weaked Ground Condition (연약지반용 스마트 앵커 공법)

  • Park, Dae-Woong;Jeong, Jong-Ki;Kim, Jeong-Ryeol
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1334-1337
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    • 2009
  • A SMART anchor is a kind of friction mount anchor, the load is diffused and applied to the various parts of the distributed bond length, having less impact on the grout strength, and being able to secure necessary anchoring force in relatively soft grounds. Smart anchor can have strong loads in soft and weak grounds as in rock beds.

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Delayed Lateral Row Anchor Failure in Suture Bridge Rotator Cuff Repair: A Report of 3 Cases

  • Jeong, Jae-Jung;Ji, Jong-Hun;Park, Seok-Jae
    • Clinics in Shoulder and Elbow
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    • v.21 no.4
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    • pp.246-251
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    • 2018
  • Compared to single row repair, use of lateral row anchors in suture bridge rotator cuff repair enhances repair strength and increases footprint contact area. If a lateral knotless anchor (push-in design) is inserted into osteoporotic bone, pull-out of the lateral row anchor can developed. However, failures of lateral row anchors have been reported at several months after surgery. In our cases, even though complete cuff healing occurred, delayed pull-out of the lateral row anchor in the suture bridge repair occurred. In comparison to a conventional medial anchor, further biomechanical evaluation of the pull-out force, design, and insertion angle of the lateral anchor is needed in future studies. We report three cases with delayed pull-out of lateral row anchor in suture bridge rotator cuff repair with a literature review.

The Study of Pullout-Behavior Characteristics of The Ground Anchor Using Expanded Hole (확공을 이용한 지압형 앵커의 인발거동 특성 연구)

  • Min, Kyong-Nam;Jung, Chan-Mook;Jung, Dae-Ho
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1502-1508
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    • 2011
  • Ground anchor expands the hollow wall of settled part and has the structure which resists the designed tensile load by the bearing pressure generated by the wedge of the anchor body pressing in the expanded part. Such ground anchor has been recognized for stability and economicality since 1960s in technologically advanced nations such as Japan and Europe, and in 1970s, the Japan Society of Soil Engineering has established and announced the anchor concept map. The ground anchor introduced in Korea, however, has the structural problem where the tensile strength is comes only from the ground frictional force due to expansion of the wedge body. In an interval where the ground strength is locally reduced due to fault, discontinuation or such, this is pointed out as a critical weakness where the anchor body of around 1.0m must resist the tensile load. Also, in the installation of concrete block, the concentrated stress of concrete block constructed on the uneven rock surface causes damage, and many such issues in the anchor head have been reported. Thus, in this study, by using the expanded bit for precise expansion of settled part, the ground anchor system was completed so that the bearing pressure of ground anchor can be expressed as much as possible, and the bearing plate was inserted into the ground to resolve the existing issues of concrete block. Through numerical analysis and pullout test executed for verification of site applicability, the pullout-behavior characteristics of anchor was analyzed.

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Development of an ACL Anchor: Effects of the Design Parameters on the Performance of a New Anterior Cruciate Ligament Fixation Device

  • Kim, Jong-Dae;Oh, Chae-Youn;Kim, Cheol-Sang
    • Journal of Biomedical Engineering Research
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    • v.29 no.2
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    • pp.132-138
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    • 2008
  • We investigated the biomechanical properties of a newly designed self-expansion type anterior cruciate ligament (ACL) anchor. The ACL anchor consists of the ring section giving the elastic force, the wedge for maintaining in contact with the femur tunnel wall and the link suspending hamstring graft or artificial ligament. The main design parameters that determine the performance of this device were the expansion angle (${\theta}$) and the thickness ($t_R$). The Ti6Al4V anchors were heated after inserting in a jig for 1 hour at $800^{\circ}C$ in a protective argon gas atmosphere and allowed to cool to room temperature in the furnace. In order to investigate the influence of the expansion angle and the thickness of the ring on the biomechanical properties of the anchor, the maximum pull-out load, stiffness and slippage of the ACL anchor were measured using the pull-out tester, and statistical analyses were also executed. The present results showed that the design parameters gave a significant effect on the performance of the self- expansion type of anchor. The pull-out load of the ACL anchors significantly increased as the thickness of the ring section was increased, having a similar trend for both expansion angles. The ACL anchor showed about 2.5 times higher values of the pull-out load than that of the minimum load (500N)required for the "accelerated rehabilitation". The optimum ${\theta}$ and $t_R$ values of this ACL anchor were suggested to have sufficient resistance against the pull-out force, high stiffness and relatively low slippage after ACL reconstruction.

Characteristic of holding power due to nature of seabed at anchor (묘박중 해저 저질에 따른 파주력 특성)

  • KIM, Byung-Yeob;KIM, Kwang-il;KIM, Min-son;NOBUO, Kimura;LEE, Chang-Heon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.58 no.3
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    • pp.230-240
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    • 2022
  • In general, a high tension on the anchor and chain is placed when a ship at anchor is subjected to heavy weather. Mariners have to pay attention to whether dragging anchor occurs to keep the safety of the ship at anchorage since it is difficult to maintain the stable motion of ship and it causes collisions with other ships nearby. In this paper, the ship motion against the external forces was shown to obtain the fundamental data about characteristic of holding power due to nature of seabed at anchor, so practical trials were carried out in rocky area and muddy area using a trial ship around coastal area of South Korea. In muddy seabed, holding power showed reasonable tension values depending on the distance from anchor position of continuing swing motions of a ship corresponding to wind force. Meanwhile in rocky seabed, tension values on the chain appeared very high occasionally regardless of the distance from the anchor position and seemed to exceed its holding power to be the breaking strain of the chain although weather was not in a severe condition. Therefore, some of the cables laid on the seabed were presumed to be caught in a crack on the rock. It is assumed that even a small amount of external force may cause the chain to break in a moment in rocky seabed. Additionally, wind and current forces had a somewhat contradictory effect on holding power of the ship between them.

Verification of Equipment Number Equation Considering New Types of Ships (선종 변화를 고려한 의장수 계산식의 적합성 검증)

  • Ku, Namkug;Ha, Sol;Lee, Kyu-Yeul;Yang, Jin-Hyeck;Bae, Jae-Ryu;Lee, Soo-Ho
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.2
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    • pp.119-124
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    • 2015
  • The purpose of this research is a verification of the current equation for calculating equipment number and a suggesting a method for development of a rational new equation. The equation for calculating equipment number consists of total surface area of a ship that fluid resistance act on. Equipment number determines the specification of anchoring and mooring equipment such as anchor weight, anchor chains length and diameter, the number, length and breaking load of tow lines and mooring lines. The equation for equipment number calculation is basically derived considering x, y components of a wind and current force acting on a ship. But this equation is only based on a tanker, which was main type of ships when the equation was derived. Therefore, verification of the equation is required for other types of ships, such as container carrier, LNG carrier, etc. Therefore, in this research, we find out the equation for equipment number calculation should be revised for other types of ships especially the container carrier, by comparing wind and current force acting on a ship to holding force of an anchor and anchor chains, which are selected based on the equipment number.

Pullout Resistance Characteristics of the Wedge-shaped Ground Anchor (쐐기형 그라운드앵커의 인발 거동 특성)

  • Kim, Jung-Moo;Chung, Won-Yong;Yoon, Yong-Soo;Chung, Min-Kyu;Jang, Soon-Ho;Lee, Yong-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.1060-1064
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    • 2010
  • Ground anchors are mostly used to improve the resistance capacity of retaining walls. The end of the anchor is connected to retaining wall through tendons and the forces in tendons are transferred to ground. In this study, we plan that the new anchor system increases the tension force in tendons and improves the pullout resistance characteristics of the system. In order to increase the pullout resistance capacity of existing anchor system, the new anchor system is made by attaching four steel sticks to the tip of anchor end. So the field test results showed that the pullout resistance capacity of the wedge-shaped ground anchor was acceptable to elastic displacement range.

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Characteristics of Anchor Behavior Resisting Buoyancy Forces in the Weathered Rock (풍화암에 시공된 부력저항 앵커의 거동특성)

  • Yoo, Nam-Jae;Lee, Gun-Chag;Jeong, Gil-Soo;Park, Byung-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.698-705
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    • 2005
  • This study contains actual scaled site experiments on mediation factors affecting ultimate pulling force of the buoyancy resisting anchor which is installed underground water level suffering buoyancy force and breaking mechanism. Site buoyancy test selected the buoyancy acting site where acting buoyancy to the station structure since the stream and reservoir is neighboured to the vicinity ground and executed site experiments leading to variation of anchoring length, drilling diameter and tendon diameter at the weathered rock ground. The test result showed that pulling force getting increased more and more proportionate to increase of anchoring length, drilling diameter and tendon diameter, and as a result of analysis for correlations between anchoring length-ultimate limited load and drilling diameter-ultimate load (on the basis of 254mm settlement), modulus of correlation showed very high relation 0.9 and 0.99 respectively and correlation formular showed the limited load is increasing proportionate to cubic meters of anchoring length as well as the ultimate load proportionate to alignment of drilling diameter. It is also showed that limited load increased about 42.5% from 392kN to 559kN as a result of change the tendon diameter to 36mm and 50mm.

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Application for Environment-friendly Retaining Wall Method Composed with Permanent Ground Anchor and Vertical Precast Panel in Cutting Slope Area (영구앵커와 연직 프리캐스트패널을 사용한 절토사면 친환경옹벽공법의 적용사례)

  • Nam, Hong-Ki;Jung, Hong-Seop
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.87-96
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    • 2010
  • PAP method is a combined measures which consist a anchored retaining wall method with permanent ground anchors and vertical precast concrete panels, step by step on the slope surface. And soil is back filled between slope and vertical precast panels. Therefore, this method is more effective than any other ground anchor reinforcing methods of slope stability, for example cross type concrete block ground anchor or buttress concrete block ground anchor method. Because of increasing effective anchor force and green tree planting.

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Development and Application of A Smart Anchor with Optical FBG Sensors (FBG 센서를 내장한 스마트 앵커의 개발과 적용)

  • Kim, Young-Sang;Suh, Dong-Nam;Kim, Jae-Min;Lee, Seung-Rae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.393-398
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    • 2008
  • With the substantial increase of the size of structure, management and monitoring of excavation for the foundation construction becomes more difficult. Therefore, massive collapses which are related to retaining wall recently increase. However, since the study on measuring and monitoring the pre-stressing force of anchor is insufficient, behavior of anchor may not be predicted and monitored appropriately by the existing strain gauge type monitoring system. FBG Sensor, which is smaller than strain gauge and has better durability and does not have a noise from electromagnetic waves, was adapted to develope a smart anchor. A series of pullout tests were performed to verify the feasibility of smart anchor and find out the load transfer mechanism around the steel wire fixed to rock with grout.

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