• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.123-131
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• 2005

In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of the anchors used in foundation system of underground structures which are applied to uplifting seepage forces. Small scaled pull-out tests in sand under saturated condition and dry condition were carried out. For estimating the group effects of the anchors, the upward displacement and the pullout load varied with spacing of the anchor were observed. The test results were compared with theoretical equation for the ultimate pull-out force. Also, the result of tests can be used to the finite element analysis program, $PENTAGON^{2D}$.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.53-62
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• 2021

For the rational application of LRFD, which is actively applied in Korea, for the study of the pull-out load and the horizontal load, which are insufficient examples, a circular foundation based on the transmission tower foundation, which is a socially important structure, through field tests in single and mixed layer. Factors that can affect the design were studied by analyzing the resistance of each stratum to pull-out and horizontal loads.

• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.615-624
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• 2006

In the present paper, an extended composite beam theory that has no restriction on the lay-up and can account for Poisson effect which is significant for composite materials is proposed. Buckling equations for composite thin-walled members which are subjected to axial compression are derived based on the composite beam theory. In order to check the validity of the derived buckling equations, the results of experiments on the flexural-torsional buckling of vinylester/E-glass and polyester/E-glass pultruded T-section members and the flexural buckling of vinylester/E-glass pultruded H-section members are used as numerical examples. The comparison of the analytical results to the experimental and FE analysis results reveals that the proposed buckling equations predict the buckling loads of pultruded members conservatively by about 7%.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.40-48
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• 2014

A number of attempts has been made to reinforce ballasted track substructure to meet the requirement of high-speed operation and effective rehabilitation of existing railroads. For the purpose of this, the use of geogrid has been applied, and the benefit of its use has been recognized via previous studies. In this study, an experimental pullout test was carried out to investigate the influence of normal stress on pullout strength of geogrid using different types of soil and geogrid. The results revealed that the pullout resistance generally tends to increase proportional to normal stress while the pullout coefficient interaction decreases, which is a function of material interface properties, such as the friction angle of soil, and interlocking condition between soil and geogrid. In addition, a methodology based on work-energy concept was proposed to evaluate effectiveness of geogrid and limitedly verified using test results.

• Journal of the Society of Disaster Information
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• v.13 no.3
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• pp.313-321
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• 2017

In order to investigate the basic performance of the high strength anchor for asphalt road subjected to tensile load, the static pullout test was carried out and the pullout strength of the asphalt anchor was analyzed. In the pullout test, the depth of anchor, depth of pavement, diameter of anchor, type of anchor, experimental temperature, epoxy type and amount of anchor were used as test variables. As a result, the steel strength of asphalt anchor was 1.08 times higher than that of conventional concrete anchor, therefore it is considered appropriate to use the steel strength formula of concrete anchor for asphalt anchor. Compared with the proposed formula, the pullout load obtained from the test of the asphalt anchor was within ${\pm}10%$. The ratio of the projected area of the asphalt anchor is similar as that of the concrete anchor.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.69-76
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• 2010

This study is an numerical study of predicting the behavior of anchor embedded in weathered rocks, subjected to uplift loads, about ultimate pullout capacity and the failure mechanism. Factors influencing the behavior of anchors were investigated by reviewing the data about in-situ anchor tests performing numerical modelling with changing the bondage length of anchor, diameter of anchor body and diameter of tendon, and by correlations between those factors were evaluated to apply them to predict the behavior of anchors. As results of numerical analysis, a linear relationship between bondage length, diameter of anchor body and diameter of tendon with ultimate pullout capacity was obtained on the one hand, from the result of numerical analysis changing the Young's modulus of weathered rock, this parameter was found to influence to load-displacement and ultimate pullout capacity within the range of 10%, which was not so significant to affect.

• Journal of the Korean Geotechnical Society
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• v.33 no.5
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• pp.37-44
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• 2017

In this study, three dimensional numerical analyses were carried out to predict axial (pullout and compressive) and lateral behavior of rock-socketed steel pipe pile varying diameter, wall thickness, and length. As a result of the pile pullout analyses, it was confirmed that the pullout displacement was inversely proportional to the pile diameter for given pile length, thickness, pullout load. Load-settlement relationship of the compressive pile analyses revealed that the effect of pile thickness on pile resistance was more significant than that of pile diameter. In addition, laterally loaded pile analyses showed that pile lateral resistance is influenced above all else by pile diameter. This study showed that it is necessary to conduct numerical analyses to identify the effects of pile diameter, wall thickness, and pile length on the steel pipe pile behavior as a preliminary pile design under specified loading conditions.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.474-482
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• 2002

The purpose of the study is to establish an optimum geometry and optimum geometry factor through bond test of a structural synthetic fiber, which fully utilizes matrix anchoring without fiber fracturing with the maximum pullout resistance. Seven deformed structural synthetic fibers with widely different geometries were investigated and pullout test was conducted. Included parameters are seven different types of fiber and two of mortar matrixes. The test result shows that the crimped type structural synthetic fiber is significant improvement in the interface toughness(pullout energy) and pullout load. The pullout test was performed with various size of crimped type structural synthetic fiber in order to invest optimum geometry factor, In the basis of the test results, optimum geometry factor is established such as D=b$^{{\alpha}0{\alpha}}$h$^{λ{\beta}}$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.41-50
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• 2014

This study evaluated the bonding property of fiber and flexural behavior of fiber reinforced concrete. Amorphous steel fiber, hooked steel fiber and polyamide fiber was used for evaluation of bonding property and flexural behavior. As a result, the hooked steel fiber was pulled out from matrix when peak stress. However amorphous steel fiber occurred shear failure because bonding strength between fiber and matrix was higher than tensile strength of fiber. Polyamide fibers occurred significantly displacement to peak stress because of elongation of fiber. After that peak stress, fiber was cut off. Amorphous steel fiber reinforced concrete had a greater maximum flexural load compared with hooked steel fiber reinforced concrete because bonding performance between fiber and matrix was high and mixed population of fiber was many. However flexural stress was rapidly reduced in load-deflection curve because of shear failure of fiber. Flexural stress of hooked steel fiber reinforced concrete was slowly reduced because fiber was pulled out from the matrix. In the case of polyamide fiber reinforced concrete, flexural stress was rapidly lowered because of elongation of fiber. However flexural stress was increased again because of bonding property between polyamide fiber and matrix. The pull-out properties of the fiber and matrix has effect on the deformation capacity and flexural strength of fiber reinforced concrete.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.303-304
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• 2003

토목합성재료 중 부직포 및 직포 지오텍스타일이 지반구조물에 적응될 경우 구속하중 부가 시 흙과의 마찰로 인한 마모에 의해 지오텍스타일의 표면손상이 발생하게 되면 강도저하가 발생하여 구조물의 안정성에 중요한 영향을 미치게 된다. 일반적으로 지오텍스타일과 흙과의 마찰특성평가는 직접전단시험이나 인발시험에 의해 평가되지만, 이들 시험 모두 구속하중에 의한 전단 및 인발변형을 해석할 뿐이며, 마모에 의한 지오텍스타일 표면 손상이나 변화는 거의 고려되지 않는 실정이다. (중략)