• Title/Summary/Keyword: anchors

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Numerical Analysis on the Behavior of a Colluvium Slope Reinforced with Soil Nails and Anchors (소일네일과 앵커로 보강된 붕적층 비탈면의 거동에 관한 수치해석)

  • Jang, Myoung-Hwan;Kim, Hoon-Tae;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.33 no.A
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    • pp.73-80
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    • 2013
  • This paper is results of numerical analysis on the behavior of colluvium slope with combinations of soil nails and earth anchors during excavation. In order to maintain the stability of the colluvium cut, being composed of gravel and boulder and thus local in stability being expected during slope cut, temporary reinforcing method of soil nailing with shotcrete might be used. Subsequent method of cast-in-place facing with earth anchors can be used to maintain cut slope stable permanently. For the cut slope where these methods had been applied, the numerical techniques were applied to their behaviors and investigate the stability of the slope. Limit equilibrium methods were used to confirm to maintain the slope stability during and after excavation and application of those reinforcing methods. Another numerical technique of FEM was also used to find the stress and strain as well as deformation distribution in reinforcing materials and slope ground during excavation.

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Creep of Plate Anchors Embedded in Bentonite (Bentonite에 근입된 앵커의 Creep 특성)

  • Shin, B.W.;Lee, J.D.;Shin, J.H.;Lee, B.J.
    • Journal of the Korean Society of Safety
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    • v.10 no.4
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    • pp.3-8
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    • 1995
  • Anchors find their use in providing tie-back resistance for submerged footings, transmission towers, tunnels and ocean structures. Laboratory model teats were performed for the short-term net ultimate uplift capacity of a circular anchors with respect to various embedment depths and moisture content in saturated bentonite. The tests have been conducted with the anchor at two different moisture contents. Based an the model test results, empirical relationships between the net load, rate of strain, and time have been developed. Test results are as follows. 1) In creep tests for load versus ultimate uplift capacity, the displacement of plate anchors rapidly increases during the primary stage but thereafter becomes constant over a period of time. 2) Displacement increased with the increase of the sustain load and embedded ratio in soil. 3) If the load is less than or equal to 75% of the short-term ultimate uplift capacity, a complete pullout does not occur due to creep.

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An Optimum Design Method for Rock Anchors Subjected to Tension (인장력을 받는 락앵커의 최적 설계법)

  • Ham, Hee-Won;Kim, Hyun-Ki;Cho, Nam-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1147-1153
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    • 2009
  • The failure modes of rock anchors subjected to tension can be defined as follows: tensile failure of tendon, shear failure on tendon-grout interface, shear failure on grout-rock interface and tensile failure of rock. This study proposes a design method to induce the rock anchor systems to avoid the brittle failure by ensuring the minimum embedded length of rock anchors. Pull-out test results of full-scale rock anchors show that the proposed method is effective in predicting the design conditions expecting the ductile tendon failure.

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The Experimental Study on the Uplift Capacity Test of Circular Anchors in Rock Mass (단일 록 앵커(Rock Anchor) 인발시험에 관한 연구)

  • 이경진;나환선;박동수;김강식;김우범
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.3-10
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    • 1999
  • There is an increasing demand for using rock anchors as foundations in many geotechnical engineering structures such as transmission towers, dams, etc. For investigate the behavior and strength of rock anchors, in-situ pull-out tests were carried out. From the tests, various forms of failure of rock anchors were observed. Ultimate capacity of each failure modes of 1) Tendon failure, 2) Interface failure(tendon-grout interface, sheath-grout interface and grout-rock interface), 3) Combined interface failure, was obtained by varying the parameters such as diameter and length of tendon, grout strength, and quality of rock.

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An Experimental Study on Suction Force of Plate Anchor Embedded in Bentonite (벤토나이트에 근입된 앵커의 흡입력에 관한 실험적 연구)

  • 이준대
    • Journal of the Korean Society of Safety
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    • v.16 no.2
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    • pp.97-102
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    • 2001
  • Anchors are often used in construction of foundations such as transmission towers to resist uplifting forces. When plate anchors are embedded in soft clay, they may undergo a deformation under the pressure of sustained load. In soft saturated clays, the suction force can be a large par of the ultimate uplift capacity. This study is to present recent laboratory model test results conducted to evaluate the nature of variation of the suction force for plate anchors with shear strength and embedment ratio. The ratio of F$_{s}$Q$_{n}$ versus H/D in bentonite decreases with the increase of the embedment ratio.o.o.

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Fracture behavior of Cast-in-place Headed Anchors to Concrete (콘크리트 CIP 앵커시스템의 파괴 거동에 관한 연구)

  • Park, Sung-Gyun;Kim, Ho-Seop;Yoon, Young-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.3
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    • pp.141-152
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    • 2001
  • This paper presents the evaluation of behavior and the prediction of tensile capacity of anchors that can cause a failure of the concrete on the basis of the design for anchorage. Tests of cast-in-place headed anchors, domestically manufactured and installed in uncracked and unreinforced concrete member are conducted to test the effected of embedment length and edge distance. The failure modes and the load-deformation responses of the anchors are discussed and then the concrete failure data are compared with capacities by the two present methods : the 45 degree cone method of ACI 349, 318 and the concrete capacity design (COD) method. Differences between the results by test and by two prediction methods are analyzed Finite Element Method (FEM).

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Conceptual Analysis of Career Anchors of Nurses (간호사의 경력 닻 개념분석)

  • Oh, Jae Woo;Kim, Mi Ran
    • Journal of Korean Academy of Nursing
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    • v.53 no.1
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    • pp.28-38
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    • 2023
  • Purpose: This study aimed to provide a theoretical basis for career anchors of nurses by defining and organizing its concept. Methods: Using the Walker and Avant concept analysis, a total of 29 articles were analyzed through a literature search in this study. Results: The career anchors of nurses are individual career choice motives, a self-concept where in competency and values are harmonized, which act as a desire for growth and development in nursing, and are actions that maintain careers. Additionally, they indicate the direction for achieving individual career goals and act as a core value expected of nurses by nursing organizations, indicating continuous and integrated professional growth and development of the nursing profession. Conclusion: The career anchors of nurses identified in the results contribute to securing patient safety, providing quality care through policies, institutionalizing bases for career development, preventing nurse turnover, and retaining skilled nurses.

Range-free Localization Based on Residual Force-vector with Kalman Filter in Wireless Sensor Networks (무선 센서 네트워크에서 칼만 필터를 이용한 잔여 힘-벡터 기반 Range-free 위치인식 알고리즘)

  • Lee, Sang-Woo;Lee, Chae-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.4B
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    • pp.647-658
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    • 2010
  • Many localization schemes estimate the locations of radio nodes based on the physical locations of anchors and the connectivity from the anchors. Since they only consider the knowledge of the anchors without else other nodes, they are likely to have enormous error in location estimate unless the range information from the anchors is accurate or there are sufficiently many anchors. In this paper, we propose a novel localization algorithm with the location knowledge of anchors and even one-hop neighbors to localize unknown nodes in the uniform distance from all the one-hop neighbors without the range information. The node in the uniform distance to its all neighbors reduces the location error relative to the neighbors. It further alleviates the location error between its actual and estimated locations. We evaluate our algorithm through extensive simulations under a variety of node densities and anchor placement methods.

The Holding Power of the Oil Boom Anchor (오일 펜스 Anchor의 파주력)

  • CHANG Duk Jong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.6
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    • pp.743-748
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    • 2003
  • An oil boom was set up in order to contain diffused oil from spills and for the retrenchment of damage caused by oil Pollution. Therefore, the oil boom anchor needed proper holding power to endure high resistance from flowing streams and to secure the oil boom around the spill, and must dredge directly into the seabed when it is dropped and block oil outflow immediately. This study investigated the holding power of the danforth anchor and the coastal fishing vessel anchor used for oil booms in the KMPRC (Korea Marine Pollution Response Corporation). For each type, a 30 kg and 20 kg anchor were used. The holding power of the danforth anchors were measured by dropping both weights 10 times. However the coastal fishing vessel anchors were dropped only 5 times each, because no substantial differences were found between drops. In the results of the danforth anchors, an anchor awoke occurred in 2 drops of the 30 kg anchor and in 4 drops of the 20 kg anchor, wherein there was no holding power to be measured. With exception to the anchor awoke cases, the maximum holding power of the danforth 30 kg and 20 kg anchors was 250-520 kg and 123-233 kg, respectively. In the case of the coastal fishing vessel anchors of 30 kg and 20 kg, throughout the experiment, there was no occurrence of an anchor awoke. For the 30 kg and 20 kg anchors, the maximum holding power was measured to be 209-230 kg and 155-170 kg, respectively. Therefore, the holding power of the coastal fishing vessel anchor was shown to be much poorer than that of the danforth anchor. However, the holding power of the danforth anchor was very unstable. Due to the occurrences of anchor awoke, there was no holding power and the measurement value of maximum holding power showed too much variation among the drop tests. Also, after the maximum holding power was achieved, anchor awoke occurred easily. In the case of the coastal fishing vessel anchor was much more stabile, because there was no anchor awoke and no instance where holding power failed. Also the maximum holding power was reached quickly and almost no variation occurred among the drop tests.

Magnetic resonance imaging analysis of screw in-type lateral anchor pull-out in large to massive rotator cuff repair in patients older than 60 years

  • Lee, Sang-Yoon;Noh, Young-Min
    • Clinics in Shoulder and Elbow
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    • v.25 no.1
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    • pp.15-21
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    • 2022
  • Background: This study was performed to identify the incidence of screw in-type lateral anchor pull-out in patients older than 60 years who underwent rotator cuff repair for large to massive rotator cuff tear (RCT). Methods: We reviewed 25 patients over 60 who were diagnosed with large to massive RCT and underwent arthroscopic rotator cuff repair in our hospital from March 2017 to February 2021. Preoperative tear size (anterior to posterior, medial to lateral) was measured via preoperative magnetic resonance imaging (MRI). All 25 patients underwent MRI scanning on postoperative day 1 and at 3 months after surgery. The change of anchor position was measured in axial views on MRI images postoperative day 1 and 3 months after surgery. And it was statistically compared according to bone mineral density (BMD), sex, and number of lateral anchors. Results: Two MRIs (postoperative day 1 and 3 months) in 25 patients were compared. Anchor pull-out occurred in six patients during 3 months (6.7%), and the mean pull-out length difference was 1.56 mm (range, 0.16-2.58 mm). There was no significant difference in the number of pull-out anchors, degree of pull-out difference by comparing BMD (A, BMD≤-2.5; B, BMD>-2.5), sex, or number of anchors used in each surgery (C, two anchors; D, three anchors) (p>0.05). Conclusions: Pull-out of screw in-type anchors was rarely observed and the mean pull-out length difference was negligibly small in our study. The screw in-type lateral anchor seems to be a decent option without concern of anchor pull-out even in elderly patients.