• Title/Summary/Keyword: Group anchor

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Horizontal pullout capacity of a group of two vertical plate anchors in clay

  • Bhattacharya, Paramita;Kumar, Jyant
    • Geomechanics and Engineering
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    • v.5 no.4
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    • pp.299-312
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    • 2013
  • The horizontal pullout capacity of a group of two vertical strip plate anchors, placed along the same vertical plane, in a fully cohesive soil has been computed by using the lower bound finite element limit analysis. The effect of spacing between the plate anchors on the magnitude of total group failure load ($P_{uT}$) has been evaluated. An increase of soil cohesion with depth has also been incorporated in the analysis. For a weightless medium, the total pullout resistance of the group becomes maximum corresponding to a certain optimum spacing between the anchor plates which has been found to vary generally between 0.5B and B; where B is the width of the anchor plate. As compared to a single plate anchor, the increase in the pullout resistance for a group of two anchors becomes greater at a higher embedment ratio. The effect of soil unit weight has also been analyzed. It is noted that the interference effect on the pullout resistance increases further with an increase in the unit weight of soil mass.

The Effect of Pressurized Grouting on Pullout Resistance and the Group Effect of Compression Ground Anchor (가압식 압축형 지반앵커의 인발저항력 증대효과 및 군효과 특성)

  • Kim, Tae-Seob;Sim, Bo-Kyoung;Lee, Kou-Sang;Lee, In-Mo
    • Journal of the Korean Geotechnical Society
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    • v.26 no.6
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    • pp.5-19
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    • 2010
  • The purpose of this study is to figure out the effect of pressurized grouting on the pullout resistance and the group effect of the compression ground anchor by performing pilot-scale chamber tests and field tests. The laboratory tests are carried out for 3-types of soils which are abundant in the Korean peninsular. Experimental results showed that the enlargement of anchor diameters estimated from the cavity expansion theory matches reasonable well with that obtained from experiments. Moreover, the required injection time as a function of the coefficient of permeability of each soil type was proposed. A series of in-situ anchor pullout tests were also performed to experimentally figure out the effect of pressurized grouting on the pullout resistance. Experimental results also showed that the effect of the pressurized grouting is more prominent in a softer ground with smaller SPT-N value in all of the following three aspects: increase in anchor diameter; pullout resistance; and surface roughness. The pressurized grouting effect in comparison with gravitational grouting was found to be almost nil if the SPT-N value is more than 50. Based on experimental results, a new equation to estimate the pullout resistance as a function of the SPT-N value was proposed. And based on in-situ group anchor pullout tests results, a new group effect equation was proposed which might be applicable to decomposed residual soils which are abundant in the Korean peninsular.

The Influence of Humor on Anchor Credibility and Viewers' Attitude toward the Anchor: A Moderating Effect of News Type (유머가 앵커에 대한 신뢰성과 시청자 태도에 미치는 영향: 뉴스 유형에 따른 조절효과)

  • Yoon, Sung-Wook;Park, Dong-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.3
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    • pp.1541-1547
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    • 2014
  • The purpose of this study is to analyze the effect of the humor on anchor credibility, attitude and to examine the moderating impact of news type. We showed two versions of the news broadcast: one with humor, the other without it to 222 university students and analyzed how the presence of humor affects on the anchor credibility, attitude and examined the moderating role of news type. The results demonstrate that the use of humor has a negative influence on anchor credibility, but doesn't affect anchor attitude. Regarding the moderating effect of news type, the group who watched soft news was not influenced by the presence of humor, but the group who watched hard news revealed that their anchor attitude became dramatically better with the use of humor.

Evaluation of Concrete Cone Breakout Strength of Expansion Anchors (익스팬션 앵커의 콘크리트 콘 파괴강도 평가)

  • Kim, Sung Yong;Kim, Kyu Suk
    • Journal of Korean Society of Steel Construction
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    • v.15 no.6 s.67
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    • pp.649-660
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    • 2003
  • The paper presents an evaluation of the tensile strength of the expansion anchor that can cause failure in the concrete based on the design of the anchorage. Tests of the heavy-duty anchor and the wedge anchor that are domestically manufactured and installed in plain concrete members are conducted to probe the effects of the embedded depth, concrete strength, and anchors spacing. The design of post-installed steel anchors is presented using the Concrete Capacity Design (CCD) approach. The CCD method is applied to predict the concrete failure load of the expansion anchor in plain concrete under monotonic loading for important applications. The concrete tension capacity of the fastenings with heavy-duty anchors and wedge anchors in plain concrete predicted using the CCD method is compared with the test results. For the CCD method, a normalization coefficient of 9.94 is appropriale for the nominal concrete breakout strength of an anchor or a group of wedge anchors in tension. On the other hand, a normalization coefficient of 11.50 is appropriate for the nominal concrete breakout strength of an anchor or a group of heavy-duty anchors in tension.

Fast and Seamless Handoff Control in Wireless ATM Networks (무선 ATM 네트워크에서 빠르고 매끄러운 핸드오프 제어)

  • Koh, Jae-Young
    • Convergence Security Journal
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    • v.7 no.1
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    • pp.99-106
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    • 2007
  • We propose a distributed anchor Crossover Switches (CX) searching algorithm to play an important role in ensuring fast and seamless handoff control in wireless ATM networks. Within networks that are grouped together, connection management is done for each group by anchor switches, and Permanent Virtual Circuit (PVC) with a narrow bandwidth is assigned between anchors for exchange of information. The proposed algorithm enables quick searching of a targeted CX, makes management of the overall network easier, and reduces system overhead or propagation delay time, thus providing fast and seamless handoff.

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A Study on the Anchoring Safety Assessment of E-Group Anchorage in Ulsan Port (울산항 E 집단정박지 묘박안전성 평가에 관한 연구)

  • Lee, Yun-Sok
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.2
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    • pp.172-178
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    • 2014
  • This study suggests the minimum critical external forces based on the assessment of anchoring safety to single anchor situation for representative 8 number of ships in E-group anchorage of Ulsan port. Assessment of anchoring safety is compared holding powers of anchor with external forces of wind, wave and current. Holding powers was reflected materials of seabed, equipment numbers regarding anchor and chain weight, also external forces acting on a hull was calculated considering projected wind area and wetted surface area to the full and ballast conditions respectively. The results of anchoring safety assessments to single anchor showed that the minimum criteria of dragging anchor is a little different from ship's type, size and loading conditions. Bulk carrier can be dragged over the 15m/s of winds and Tanker can be dragged over the 13m/s of winds in case of less than 2knots of currents speed.

Small Scaled Pull-out Tests on Group Effect of Screw Anchors in Saturated Sand (포화토내 나선형 앵커의 무리효과에 관한 실험적 고찰)

  • 김홍택;권영호;박사원;최영하
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.387-394
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    • 2000
  • In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of underground structures applied uplift seepage forces. Small scaled pull-out tests in sand were conducted under saturated condition. And then, it was observed that the upward displacement as well as the pullout load varied with spacing of the anchor. Also, analyses have been performed with the aim of pointing out the effects of various parameters on the group effect of the screw anchors.

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A Study on the Behaviour of Jacket Anchor (자켓앵커 거동특성에 관한 연구)

  • Kim, Dong-Hee;Kim, In-Chul;Kong, Hyun-Seok;Lee, Woo-Jin
    • Journal of the Korean Geotechnical Society
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    • v.24 no.8
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    • pp.89-97
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    • 2008
  • A series of field tests were performed to investigate the behavior of jacket anchor and to evaluate the ultimate bond stress of jacket anchor. From twelve sets of field tests on the jacket anchor and general type ground anchor, it was observed that the pullout resistance of jacket anchor is significantly larger than that of the ground anchor and that the plastic deformation of jacket anchor is significantly smaller than that of general ground anchor at the same loading cycle. Especially in gravel layers, the jacket anchor provides more than 250% increase in ultimate resistance and more than 600% reduction in plastic deformation, compared with the general ground anchor. Finally, the relationship between the injection pressure and overburden pressure is proposed to determine the optimum injection pressure, based on additional field test results.

Shear Strength of Anchors under Load Applied Angle and a Group Anchors at an Edge (앵커간격 및 하중방향에 따른 앵커의 전단내력)

  • Kim, Sung-Yong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.3 no.3 s.10
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    • pp.133-141
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    • 2003
  • This study concerns the prediction of shear capacity, as governed by concrete breakout failure of the anchors under load applied angle and an group anchors at an edge and installed in uncracked, unreinforced concrete. For this purpose, the methods to evaluate the shear capacity of the anchors in concrete are summarized and the experimental data are compared with capacities by the two present methods: the method of ACI 349-90 and concrete capacity design (CCD) method.

Outcomes after Arthroscopic Repair of Anterior Shoulder Instability after Metal Anchor to Biodegradable Anchor Fixation (견관절 전방 불안정성에 대한 관절경 치료 결과: 금속 나사못 및 흡수성 나사못 고정의 결과 비교)

  • Choi, Chang-Hyuk;Kim, Shin-Kun;Han, Bo-Ram
    • Clinics in Shoulder and Elbow
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    • v.11 no.2
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    • pp.158-164
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    • 2008
  • Purpose: We compared the results of arthroscopic Bankart repair using metal and biodegradable anchor fixation. Materials & Methods: We reviewed 26 patients with anterior shoulder instability treated by arthroscopic Bankart repair from October, 2006, to March, 2007, 15 patients with metal anchors and 11 patients with biodegradable anchors. The average age was 27.4 years old (range: 17~55) and mean follow-up was 14 months (range: 12~17 months). Functional outcome was evaluated using the Korean Shoulder Score for Instability (KSSI), Rowe's Bankart Grading scale (RBGS), ASES score, and UCLA scores. Results: In the metal-anchor group, the improvements of mean KSSI, ASES, UCLA score, and RBGS were 20.6, 24.0, 4.0, and 45.5, respectively. In the biodegradable anchor group, improvements of mean KSSI, ASES, UCLA score, and RBGS were 21.0, 23.6, 4.6, and 48.9. The improvements in final outcomes were not significantly different (p>.05). One metal problem and one traumatic redislocation occurred in the metal group. Conclusion: Both techniques produced satisfactory outcomes in the treatment of traumatic anterior instability. The biodegradable anchor group could also avoid problems with metal anchors.