• Title/Summary/Keyword: Anchorage test

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Anchorage Behavior of Bi Prestressed Concrete Girders (프리스트레스트 콘크리트거더의 정착구 거동 분석)

  • Lee, Pil-Goo;Kim, Choong-Eon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.361-364
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    • 2008
  • This study was performed to estimate the anchorage behavior for Bi Prestressed Concrete Girder(Bicon girder) which could introduce effectively prestressed forces into concrete girders. A bicon girder is manufactured by means of introducing pure bending moment that prestress simultaneously the compressive member(steel bar) and the tensile member(steel tendon). Therefore, the steel bar and the steel tendon must be unified in both ends and compressive and tensile force be offset. Anchorage dimension of 6 test specimens was designed under PTI specification which defined maximum stress and deformation to estimate structural behavior. Test results showed that the stress and the deformation of anchorage were within limits if the steel bar behaviored elastically.

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Mechanical Bar Anchorage of the PC Beam in Beam-Column Joint Using Plates and Bolts (지지대 및 제결볼트를 이용한 프리캐스트 콘크리트 골조구조의 보 하단 철근 정착공법 개발)

  • 유영찬;최근도;김긍환;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.539-544
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    • 2000
  • The purpose of this study is to develop the mechanical anchorage, namely MAB-BOP (Mechanical Anchorage of 90$^{\circ}$ Hooked Bars with BOlt nad Plate) of the beam-column joint in precast concrete framed structures. Six specimens simulating typical interior beam-column joints were tested to investigate the mechanical characteristics of MAB-BOP. Of primary interest was the measurement of the slip of the anchored bar. Th load-slip curve obtained from this test were used to compare the mechanical performances of the different anchoring methods. Based on the test results, it was found that MAB-BOP showed sufficient anchoring strength capacity compared to 90$^{\circ}$ hooked bar method. So, MAB-BOP can be used as the anchoring methods of the reinforcing bars in PC beam-column joint.

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Evaluate Anchorage Strength of High Relative Rib Area Bars Using Hook Test Specimens (갈고리 시험체를 이용한 높은마디면적 철근의 정착성능)

  • Seo Dong Min;Hong Gi Suop;Choi Dong Uk;Choi Oan Chul
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.327-330
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    • 2005
  • Bond failure of reinforcing bar generally take place by splitting of the concrete cover as bond force between concrete and reinforcing bars exceeds the confinement of the concrete cover and reinforcement. However, the confinement force in practice has a limitation. Thus, the only variable is the bearing area corresponding to the change of bond force. In this study, to the evaluate anchorage strength of high relative rib area bars, hook bond test specimens are tested and the results are discussed. Higher rib height bars when bars are confined showed higher anchorage strength than lower rib higher bars.

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Structural Behavior of RC Columns with Mechanically Anchored Crossties under Cyclic Loading (기계적 정착된 전단보강근을 가진 RC 기둥의 구조적 거동)

  • Lee, Sung-Ho;Chun, Sung-Chul;Oh, Bo-Hwan;Nah, Hwan-Sean;Kim, Sang-Koo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.59-62
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    • 2005
  • Seven columns laterally reinforced with either mechanically anchored crossties or conventional crossties under cyclic loading are tested. 4 columns are specimens for flexural strength and 3 columns are for shear strength. Main variable is anchorage types of crossties. Conventional hooks, 180$^{\circ}$ standard hook-mechanical anchorage and all mechanical anchorage type are used. The specimens are tested under 10$\%$ axial load of nominal axial capacity of the columns combined with increasing lateral load. From the flexure test, it is found that columns with mechanical anchorages exhibit superior performance in terms of ductility and energy dissipation. The crossties with mechanical anchorages reduce buckling length of longitudinal rebar. From the shear test, it is found that. 3 specimens exhibit almost the same strength, displacement, and shear failure mode at ductility factor =2.

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Experimental Study on Wedge-type Anchorage System for CFRP Laminates (CFRP판용 쐐기형 정착장치에 대한 실험적 연구)

  • Park, Jong-Sup;Park, Young-Hwan;Jung, Woo-Tai
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.157-160
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    • 2006
  • Carbon fiber reinforced polymer (CFRP) laminates can be used more efficiently in strengthening applications by applying prestress to the CFRP laminates. A key problem for prestressing with CFRP laminates is anchoring the laminates. These may include fracture to the CFRP laminates due to excessive gripping force or slippage of the CFRP laminates out of the anchorage zone caused by low friction between the anchor device and the lamiantes. The main objective of this study is the development of an applicative wedge-type anchorage system for prestressed CFRP laminates through experimental study. The experimental parameters were the type of anchorage and the effect of elastic modulus of tab. The test results showed that the developed anchor assures 100% CFRP laminate strength.

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An Experimental Study on the Anchorage Capacity by Diameter and Anchor Type of Re-bar (콘크리트 구조체 매입 철근의 직경 및 유형별 앵커력 측정실험 연구)

  • Cho, Seong-Yeol;Son, Ki-Sang
    • Journal of the Korean Society of Safety
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    • v.29 no.5
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    • pp.67-73
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    • 2014
  • Construction equipment such as tower crane should be installed in a field without appropriate anchorage to cause a collapse of crane. The anchorage capacity can be varied with Anchor length, concrete strength, anchor diameter, hooked or non hooked these variables will be made and tested in the study. It is shown what anchorage capacity will be more effective case by case. Hooked and non-hooked rebar anchor concrete weight with dia 22mm rebar are shown with initial displacement at 170~220KN of hooked case and 200~210KN of non-hooked one which are linearly increased, without any ductility behavior with almost brittleness. Three(3) same test pieces are almost similarly behaviored without relation to hooked or non-hooked cases. It is found out that the bigger diameter of rebar becomes, the more resistant capacity could be made, but conversely ductility against sudden collapse similar to brittleness becomes the more insufficient. It is also found out that dia 16mm rebar could be more effectively applied to heavy support weight at construction sites.

Experimental Analysis of Anchorage Zone Design for Unbonded Post-Tensioned Concrete Beam With 2400MPa Single Tendons (2400MPa 단일 강연선이 적용된 포스트텐션 정착 구역 설계에 대한 실험적 연구)

  • Moon, Sang Pil;Ro, Kyong Min;Kim, Min Sook;Lee, Young Hak
    • Journal of Korean Association for Spatial Structures
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    • v.20 no.1
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    • pp.41-48
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    • 2020
  • In this study, the design of anchorage zone for unbonded post-tensioned concrete beam with single tendons of ultimate strength 2400MPa was evaluated to verify that the KDS 14 20 60(2016) and KHBDC 2010 codes are applicable. The experimental results showed that the bursting force equation of current design codes underestimated bursting stress measured by test, because the KDS 14 20 60(2016) and KHBDC 2010 propose the location of the maximum bursting force 0.5h which is the half of the height of member regardless of stress contribution. Although the allowable bearing force calculated by current design codes was not satisfied the prestressing force, the cracks and failure in anchorage zone was not observed due to the strengthening effect of anchorage zone reinforcement.

Evaluation of Flexural Performance of Reinforced Concrete Beams Strengthened by Carbon Fiber Sheet Considering End Anchorage Effect (탄소섬유시트로 보강한 RC보의 단부 정착유무에 따른 휨성능 평가)

  • Lee, Chang-Hyun;Eo, Seok-Hong
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.6_3
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    • pp.1165-1171
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    • 2022
  • In this paper, the results of an experimental study were presented by measuring and comparing the flexural strength and deformation on the carbon fiber sheet strength reinforced concrete beam considering end anchorage effect. For this purpose, total six specimens of 100×100×600mm size were prepared and tested according to the KDS 14 20 20. The specimens were categorized in three cases as reference beams without strengthening, beams carbon fiber strengthened but not anchored and beams carbon fiber strengthened also anchored. Experimental results showed that the end anchorage contributed to increase the flexural strength about 42% greater than that of carbon fiber sheets alone, and the number and width of cracks were relatively increased. The results support a considerable effects of end anchorage for carbon fiber strengthened reinforced concrete beams in enhancing the flexural performance. Further studies are needed in durability and long term behavior of carbon fiber sheet strengthened reinforced concrete beams.

Preliminary three-dimensional analysis of tooth movement and arch dimension change of the maxillary dentition in Class II division 1 malocclusion treated with first premolar extraction: conventional anchorage vs. mini-implant anchorage

  • Park, Heon-Mook;Kim, Byoung-Ho;Yang, Il-Hyung;Baek, Seung-Hak
    • The korean journal of orthodontics
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    • v.42 no.6
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    • pp.280-290
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    • 2012
  • Objective: This study aimed to compare the effects of conventional and orthodontic mini-implant (OMI) anchorage on tooth movement and arch-dimension changes in the maxillary dentition in Class II division 1 (CII div.1) patients. Methods: CII div.1 patients treated with extraction of the maxillary first and mandibular second premolars and sliding mechanics were allotted to conventional anchorage group (CA, n = 12) or OMI anchorage group (OA, n = 12). Pre- and post-treatment three-dimensional virtual maxillary models were superimposed using the best-fit method. Linear, angular, and arch-dimension variables were measured with software program. Mann-Whitney U-test and Wilcoxon signed-rank test were performed for statistical analysis. Results: Compared to the CA group, the OMI group showed more backward movement of the maxillary central and lateral incisors and canine (MXCI, MXLI, MXC, respectively; 1.6 mm, p < 0.001; 0.9 mm, p < 0.05; 1.2 mm, p < 0.001); more intrusion of the MXCI and MXC (1.3 mm, 0.5 mm, all p < 0.01); less forward movement of the maxillary second premolar, first, and second molars (MXP2, MXM1, MXM2, respectively; all 1.0 mm, all p < 0.05); less contraction of the MXP2 and MXM1 (0.7 mm, p < 0.05; 0.9 mm, p < 0.001); less mesial-in rotation of the MXM1 and MXM2 ($2.6^{\circ}$, $2.5^{\circ}$, all p < 0.05); and less decrease of the inter-MXP2, MXM1, and MXM2 widths (1.8 mm, 1.5 mm, 2.0 mm, all p < 0.05). Conclusions: In treatment of CII div.1 malocclusion, OA provided better anchorage and less arch-dimension change in the maxillary posterior teeth than CA during en-masse retraction of the maxillary anterior teeth.

Analysis of Pull-out Behavior of Tunnel-type Anchorage for Suspended Bridge Using 2-D Model Tests and Numerical Analysis (2차원 모형실험 및 수치해석을 통한 현수교 터널식 앵커리지의 인발거동 특성 분석)

  • Seo, Seunghwan;Park, Jaehyun;Lee, Sungjune;Chung, Moonkyung
    • Journal of the Korean Geotechnical Society
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    • v.34 no.10
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    • pp.61-74
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    • 2018
  • In this study, the pull-out behavior of tunnel type anchorage of suspension bridges was analyzed based on results from laboratory size model tests and numerical analysis. Tunnel type anchorage has found its applications occasionally in both domestic and oversea projects, therefore design method including failure mode and safety factor is yet to be clearly established. In an attempt to improve the design method, scaled model tests were conducted by employing simplified shapes and structure of the Ulsan grand bridge's anchorage which was the first case history of its like in Korea. In the model tests, the anchorage body and the surrounding rocks were made by using gypsum mixture. The pull-out behavior was investigated under plane strain conditions. The results of the model tests showed that the tunnel type anchorage underwent wedge shape failure. For the verification of the model tests, numerical analysis was carried out using ABAQUS, a finite element analysis program. The failure behavior predicted by numerical analysis was consistent with that by the model tests. The result of numerical analysis also showed that the effect of Poisson's ratio was negligible, and that a plugging type failure mode could occur only when the strength of the surrounding rocks was 10 times larger than that of anchorage body.