• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.529-536
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• 2011

Recently, there has been a growing interest in expanded sidewalks for existing bridges. The cantilever beam system applied to expanded sidewalks for existing bridges are connected with the concrete structure by adhesive anchor bolts. However, the extended sidewalks are currently constructed without standardized regulations, which lead to excessive design of the beam spacing and installation and the construction difficulties due to the excessive over-weight. Moreover, there is only limited analysis and experiment data on the post-installed adhesive anchor bolts, so the excessive number of bolts is used for the connection. This paper deals with a method to increase the effectiveness of beam sections and anchor bolts geometry for expanded sidewalk of existing bridge. The study results showed that the failure of cantilever beam connected by adhesive anchor bolts was dominated by bond failure of interface between concrete and bolt. Also, the results indicated the possibilities of improving serviceability as well as safety of the sidewalks by changing of beam section and prestressing the bolts.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.555-563
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• 2006

Recently, many bridges become not only functionally obsolete of bridge deck due to inadequate width but also structurally deficient of substructure due to erosion. In these cases, widening is almost always more economical than complete replacement, and therefore there is a need to make available the results of research and field experience pertaining to the widening of bridge substructure. But, an experimental study for the guarantee of unification between existing and new substructure with adhesive anchor is so insufficient that the development of adhesive anchor system for the unification should be settled promptly. The purpose of the present study is to explore pull out and shear characteristics of adhesive anchor system. For this purpose, several series of concrete specimens have been tested. Major test variables were the bonded length, anchor diameter and anchor slope. The pull out strength, bond stress and shear strength of adhesive faces were measured for the specimens. The present study indicates that the pull out strength increased with more bonded length and more anchor diameter, and that the bond stress decreased with more bonded length and more anchor diameter. The pull out strength and the bond stress increases with more anchor slope and it is considered that the slope of $5^{\circ}$ was more efficient. From the shear tests, it is supposed that anchor diameters more than D19 was proper to the adhesive anchor. Finally, it is expected that both experimental data in these tests and further study including mock-up tests will contribute to the establishment of the unification between existing and new substructure with adhesive anchor.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.21-29
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• 2017

The use of post installed anchors with adhesive type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with adhesive type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on adhesive strength of anchors embedded into plain concrete by shear experiments of anchors with variables such as edge distance, anchor interval, and load direction and supplying basic data for enactment of domestic design code.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.105-114
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• 2018

The use of post installed anchors with bond type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post-installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with bond type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on pull-out strength of resin anchors embedded into plain concrete by pull-out experiment of resin anchors with variables such as anchor diameter, anchor interval, embedment depth and edge distance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.66-71
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• 2018

In general, when an existing pier is enlarged and reinforced using a small diameter pile, bonded anchor with deformed reinforcing bars is used to maintain the integrity of the joint. However, in the case of bonded anchors, the performance depends largely on the type of joint material. Nevertheless, unlike mechanical anchors, there is no standard method for designing appropriate design methods and proper performance evaluation. Therefore, in this study, the performance of the anchoring anchor was evaluated by performing a model experiment using the reinforcing bars and anchor reinforcing bars. Experimental results show that the structural performance of the unbonded specimen is the best, and the failure mode is the punching shear failure. The deflection of the end of the member is smaller than that of the unconnected member, The deflection of the connected member is larger than the deflection of the small connected member. As the load increases, the possibility of slippage of the anchor steel or fold connection rebar is high.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.156-156
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• 2011

중량물 혹은 철골구조물 등을 고정시키는데, 건축구조물의 철골기둥, 터빈 제네레이터 기기등을 콘크리트 구조물에 부착시키기 위해 널리 쓰인다. 1990년대 들어 국내 건물의 리모델링, 보수 및 유지관리의 증가에 따라 앵커의 사용량도 현저히 증가하고 있으나 대부분 고가의 외국산제품을 수입하고 있다. 현재 국내외에 주로 시행되는 앵커타입은 마찰형 앵커이나 마찰형 앵커와 달리 지압형 앵커의 경우, 외국에서는 이미 그 유효성에 대한 인식이 널리 퍼져있으며 각국의 지반조건에 적합한 설계법이 개발되었다. 그러나 국내의 경우 이러한 연구가 미진한 실정이며 이에 대한 연구가 절실한 상황이다. 본 연구에서는 중량물앵커(Heavy Duty Anchor)의 인장시험을 실시하여 내력을 규명하고 도출한 결과를 기존 시험연구 결과와 비교분석하여 기 제안된 이론식들과 사업경제성에대해 보다 깊이있고 정확한 적용성을 입증하는데 본 연구를 수행하였다. 시험을 통한 저강도 파괴시험의 결과 구조부재의 접합부에서 각 시험체마다 뽑힘파괴가 발생하였으며, 뽑힘파괴가 발생한 시험체는 앵커강재의 파괴력 또는 콘크리트의 콘파괴를 발생시키기에는 앵커슬리브의 확장력이 작게 작용되었다. 그 결과, 콘파괴 대신 구조부재의 접합부에서 뽑힘파괴가 발생되었으며 이를 통해 설계시, 앵커의 안정성을 증가시키기 위해 구조부재의 접합부를 연성적이며, 부가여력을 충분히 지니도록 설계하는 것이 효과적인 것으로 나타났다. 고강도 파괴시험의 결과 콘파괴가 발생되었음을 알 수 있는데, 본 시험에 사용된 앵커의 경우 정착위치가 구조물의 연단 모서리 거리와 너무 근접하여 앵커의 내력이 감소하게 되어 콘크리트의 콘강도가 발생되기 전에 먼저 파괴되었다. 따라서 설계시, 앵커의 파괴강도를 증가시키기 위해 앵커의 정착위치를 고려한 설치를 통해 앵커체결과정에서 적정 연단거리를 확보하는 것이 효과적인 것으로 나타났다. 앵커볼트 최소간격과 연단거리에 따른 파괴시험결과 앵커볼트의 간격이 허용범위 내에서 넓어질수록 불균등 부반력의 차는 감소하였으며, 최대 부반력도 감소하였다. 따라서 앵커의 파괴저항강도를 증가시키기 위해서는 허용범위 내에서 앵커볼트의 설치간격을 증가시키는 것이 효과적인 것으로 나타났다.

• Geotechnical Engineering
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• v.11 no.1
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• pp.63-78
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• 1995

Recently, in order to utilize more effectively underground space, deep excavations have been performed on building or subway construction in urban areas. In such excavations, anchors have been used to support the excavation retaining walls because the anchored excavation could provide wide working space for underground construction. The purpose of this paper is to establish empirical equations to be able to estimate the earth pressures acting on anchored excavation retention walls, based on the investigation of field measuring results, which were obtained from twenty seven building construction sites. The prestressed anchor force was measured by load cells which were attached to the anchor head, while the horizontal displacement of excavation walls were measured by inclinometers which were installed right'behind the retention walls. The lateral earth pressures acting on the anchored retention walls, which were estimated from both the measured anchor forces and the horizontal displacement of the walls, showed a trapezoidal distribution. There was some difference between the measured earth pressures acting on the anchored retention walls and the empirical earth pressures given by several empirical equations. Thus, the lateral earth pressures acting on anchored retention walls would be estimated by these empirical equations with some modifications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2414-2418
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• 2014

This study carried out three-dimensional finite element analysis and structural safety evaluation of attachable roadside barriers. The effects of diaphragm distance and the number of bolts on displacements and maximum stresses for various parameters are studied using the LS-DYNA finite element program for this study. In this study, the existing finite element analysis of barriers using the LS-DYNA program is further extended to study static behaviors and structural safety of the barrier with module structures connected by anchor bolt inserted through concrete bridge decks. The numerical results for six parameters are verified by comparing different models with displacements and stress distribution occurred in the barrier and shows good structural performance.

• Land and Housing Review
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• v.7 no.4
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• pp.281-289
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• 2016

Structural experiment result showed that PHC(d=600mm) Pile used as a common compression member could resist 83.6 ~ 91.6 tonf of ultimate tension force, if the adhesion of P.C. bar of PHC pile to the concrete foundation is strengthened. Considering a proper safety factor to ultimate tension strength, PHC pile can substitute the anti-floating anchor, or reduce the number of anchors. For this purpose, pullout resistance behavior of a Bored pile embedded in real ground as well as structural tension strength of PHC pile must be evaluated. This study performed the static pullout tests to evaluate the pullout behavior of bored pile, and compared the test results with design value of side resistance. To evaluate the pullout resistance easily, static pullout test results were compared with dynamic loading test results using PDA. As a result, cement paste of the bored pile was hardened which is after 15 days, LH side resistance design value corresponded well to the Static pullout test results, also to the side resistance evaluated by dynamic loading test.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.1
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• pp.1-12
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• 2005

An analytical procedure to analyze reinforced concrete (RC) beams subject to monotonic loadings is proposed on the basis of the moment-curvature relations of RC sections. Unlike previous analytical models which result the overestimation of stiffnesses and underestimation of structural deformations induced from ignoring the shear deformation and assuming perfect-bond condition between steel and concrete, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end. The advantages of the proposed relation, compared with the previous numerical models, are on the promotion in effectiveness of analysis and reflection of influencing factors which must be considered in nonlinear analysis of RC beam by taking into account the nonlinear effects into the simplifying moment-curvature relation. Finally, correlation studies between analytical and experimental results are conducted to establish the applicability of the proposed model to the nonlinear analysis of RC structures.