• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.145-146
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• 2009

In this paper, feasibility tests of 2200MPa PS strand in terms of wedge and anchor head used currently for 1860MPa PS strand were performed. Static and fatigue tests for PT anchorage systems from 4 companies were conducted in compliance with ETAG013(European Technical Approval Guideline). The test results implied that some of them can be used for 2200MPa PS strand without improvement and some with small improvement.

• Journal of Biomedical Engineering Research
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• v.29 no.2
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• pp.132-138
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• 2008

We investigated the biomechanical properties of a newly designed self-expansion type anterior cruciate ligament (ACL) anchor. The ACL anchor consists of the ring section giving the elastic force, the wedge for maintaining in contact with the femur tunnel wall and the link suspending hamstring graft or artificial ligament. The main design parameters that determine the performance of this device were the expansion angle (${\theta}$) and the thickness ($t_R$). The Ti6Al4V anchors were heated after inserting in a jig for 1 hour at $800^{\circ}C$ in a protective argon gas atmosphere and allowed to cool to room temperature in the furnace. In order to investigate the influence of the expansion angle and the thickness of the ring on the biomechanical properties of the anchor, the maximum pull-out load, stiffness and slippage of the ACL anchor were measured using the pull-out tester, and statistical analyses were also executed. The present results showed that the design parameters gave a significant effect on the performance of the self- expansion type of anchor. The pull-out load of the ACL anchors significantly increased as the thickness of the ring section was increased, having a similar trend for both expansion angles. The ACL anchor showed about 2.5 times higher values of the pull-out load than that of the minimum load (500N)required for the "accelerated rehabilitation". The optimum ${\theta}$ and $t_R$ values of this ACL anchor were suggested to have sufficient resistance against the pull-out force, high stiffness and relatively low slippage after ACL reconstruction.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.538-545
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• 1997

기기 및 각종 지지부의 정착을 위해 사용되는 콘크리트 확장형 앵커(CEA Concrete Expansion Anchor)인 PRH Wedge, Selfdrilling 및 Hilti KBII, HSLG에 대해서 최근 Canada의 Mcmaster 대학과 Switzerland 의 Schann 연구소에서 앵커 성능시험이 수행되었다. 본 시험결과를 토대로 월성원자력 2,3,4호기 설계앵커인 PRH Wedge, Selfdrilling 및 Hilti KBII와 대체앵커인 HSLG 앵커의 사용범위에 대해서 살펴보았다. 또한 동일한 앵커에 대해서 수행된 성능시험이라 할지라도 시험결과는 시편크기, 콘크리트강도 등 시험적용 변수에 따라 달라질 수 있는데 보고에서는 시험시편(Concrete Structural Member)의 크기에 따른 앵커링 파괴강도 및 콘크리트 파괴형태의 고찰을 통해 기존의 앵커시험 및 사용기준인 ASTM E488-90 [5], ACI 355.1R [6] 둥 제규정과의 차이점에 대해 고찰하고자한다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.404-404
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• 1996

In order to ensure a concrete expansion anchor is suitable for a given application, the load resistance behavior of the anchor must be known. ASTM E488 provides a standard method of testing expansion anchors for static and dynamic loads. Due to the many types of anchors available commercially and the large variability of applications, the ASTM does not delineate all details or requirements necessary to comprehensively determine the dynamic load behavior of concrete expansion anchors. A test program is presented in this paper which was developed and implemented to determine the cyclic load behavior of wedge-type concrete expansion anchors. Test results are also presented along with a discussion of the behavior of anchors, and their suitability for use.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1369-1375
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• 2006

This study analyzes stability and the reason of slope failure about cut slope on stony mountain in Acheondong, Guri and suggests the reasonal reinforce method. Based on the results of the subsurface exploration, laboratory tests, and the numerical analysis of finite element method, the potentials of plane and wedge failure are highly estimated. The safety factor was 1.2 under dry and 1.06 wet condition. The most proper reinforce method to raise the safety factor more than 1.5 was the way to control displacement by using step retaining wall, earth anchor, wire mesh, and rock anchor.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.171-181
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• 2003

This study concerns the prediction of shear capacity, as governed by concrete breakout failure, concrete pryout failure and steel failure, of single anchors located close to free edge and located far from a free edge and installed in uncracked, unreinforced concrete. For this purpose, the methods to evaluate the shear capacity of the single 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.

• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.19-27
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• 2013

Recently, the natural and man-made slope collapses occur frequently because of sudden heavy rains. So, a variety of slope reinforcement methods have been developed and applied to failure slopes. Soil nailing method usage has been increased because of its workability and economic aspects. This method has been applied in combination with other slope stability methods. Soil nailing method is a kind of combinational structure of steel bar and cement grouting. This method uses skin friction between adjacent ground and cement grouting to stabilize the slope. In this study, End-expanded soil nailing method was developed. This method consists of steel bar and anchor body attached at the tip of the nail. During construction, the anchor body at steel bar tip is settled to the ground through the expanding action. In this study, field pull-out tests were performed for un-grouting soil nailing and grouting soil nailing. From the test results, a wedge force of End-expanded soil nailing method was analyzed. And the behavior characteristics of End-expanded soil nailing were studied.

• Geomechanics and Engineering
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• v.24 no.5
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• pp.457-470
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• 2021

In this study, the pull-out behavior of a tunnel-type anchorage for suspension bridges was investigated using experimental tests and image processing analyses. The study focused on evaluating the initial failure behavior and failure mode of the tunnel-type anchorage. In order to evaluate the failure mode of tunnel-type anchorage, a series of scaled model tests were conducted based on the prototype anchorage of the Ulsan Grand Bridge. In the model tests, the anchorage body and surrounding rocks were fabricated using a gypsum mixture. The pull-out behavior was investigated under plane strain conditions. The results of the model tests demonstrate that the tunnel-type anchorage underwent a wedge-shaped failure. In addition, the failure mode changed according to the differences in the physical properties of the surrounding rock and the anchorage body and the size of the anchor plate. The size of the anchor plate was found to be an important parameter that determines the failure mode. However, the difference in physical properties between the surrounding rock and the anchorage body did not affect its size. In addition, this study analyzed the initial failure behavior of the tunnel-type anchorage through image analysis and confirmed that the failure was sequentially transferred from the inside of the tunnel to the surrounding rock according to the image analysis. The reasonable failure mode for the design of the tunnel-type anchorage should be wedge-type rather than pull-out type.

• Journal of the Korean GEO-environmental Society
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• v.14 no.8
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• pp.37-44
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• 2013

The superiority of bearing ground anchor system has been recognized for the stability and economical efficiency since 1950s in Japan, Europe and etc. The ground anchor introduced in Korea, however, has the structural problem that the tensile strength comes only from the ground frictional force caused by the expansion of the wedge body and it is impossible to evaluate the bearing resistance because the adhering method of the anchor body to hollow wall is not appropriate. In this study, the underreamed ground anchor system was developed so that the bearing pressure of ground anchor can exert as much as possible. And the in-situ tests were performed to evaluate the pullout behavior characteristics and to verify the decreasing effect of the bonded length. The pullout tests were performed with the non-grouted tension condition and grouted tension condition in order to identify the pull-out resistance of each conditions. In addition, it was compared with the results of friction anchor. Finally, the numerical analysis was fulfilled to verify the bearing effect at the bonded part through the detailed modeling by PLAXIS-2D, which is general finite element method analysis program.

• Smart Structures and Systems
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• v.16 no.3
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• pp.415-433
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• 2015

Tendon failures in bonded post-tensioned bridges over the last two decades have motivated ongoing investigations on various aspects of unbonded tendons and their monitoring methods. Recent research shows that change of strain distribution in anchor heads can be useful in detecting wire breakage in unbonded construction. Based on this strain variation, this paper develops a damage detection model that enables an automated tendon monitoring system to identify and locate wire breaks. The first part of this paper presents an experimental program conducted to study the strain variation in anchor heads by generating wire breaks using a mechanical device. The program comprised three sets of tests with fully populated 19-strand anchor head and evaluated the levels of strain variation with number of wire breaks in different strands. The sensitivity of strain variation with wire breaks in circumferential and radial directions of anchor head in addition to the axial direction (parallel to the strand) were investigated and the measured axial strains were found to be the most sensitive. The second part of the paper focuses on formulating the wire breakage detection framework. A finite element model of the anchorage assembly was created to demonstrate the algorithm as well as to investigate the asymmetric strain distribution observed in experimental results. In addition, as almost inevitably encountered during tendon stressing, the effects of differential wedge seating on the proposed model have been analyzed. A sensitivity analysis has been performed at the end to assess the robustness of the model with random measurement errors.