• Geomechanics and Engineering
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• v.14 no.5
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• pp.429-437
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• 2018

In order to reduce deformation of roadway floor heave in deep underground soft rockmass, four support design patterns were analyzed using the Fast Lagrangian Analysis of Continua (FLAC)3D, including the traditional bolting (Design 1), the bolting with the backbreak in floor (Design 2), the full anchorage bolting with the backbreak in floor (Design 3) and the full anchorage bolting with the bolt-grouting backbreak in floor (Design 4). Results show that the design pattern 4, the full anchorage bolting with the bolt-grouting backbreak in floor, was the best one to reduce the deformation and failure of the roadway, the floor deformation was reduced at 88.38% than the design 1, and these parameters, maximum vertical stress, maximum horizontal displacement and maximum horizontal stress, were greater than 1.69%, 5.96% and 9.97%. However, it was perfectly acceptable with the floor heave results. The optimized design pattern 4 provided a meaningful and reliable support for the roadway in deep underground coal mine.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.425-430
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• 2002

This thesis is a study on behavior for anchorage zone in prestressed double T beam using strut-tie model. Stress conditions of Anchorage zone in prestressed double T beam are very disturbed because large concentrated forces act on relatively small areas. Hence, anchorage zone must be considered in Design of prestressed double T beam. If irrational design or irrational construction be conducted, that may lose stability in capacity as structure. In current design practice, certain parts of structure are designed with extreme accuracy, while anchorage zone in prestressed double T beam is designed using common sense, and experience. Therefore, it is generally very conservative. For that reason, logical, reasonable concept and accuracies are desired at design of anchorage zone in prestressed double T beam. Strut-tie method satisfies those desires. In this thesis, anchorage zone in prestressed double T beam is analyzed by considering prestressing forces. Strut-tie model is constructed based on principle stress trajectory obtained from 3D-finite element analysis in anchorage zone, and amounts of reinforcement be obtained. Results of analysis are compared with the way used in current design practice, and this thesis presents that strut-tie model can be an economical design than current design methods without losing the degree of safety.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.215-223
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• 2000

In this study, the effect of stiffness ratio between base frame and anchorgae is evaluated and the seismic verification of nuclear power plant equipment anchorage is performed for typical equipment. The stiffness ratio between base frame and anchorage is mainly controlled by the effective height of side wall plate. And, the change of that stiffness ratio cause the large shift or ovreturning axis of equipment base. This shift of overturning axis of equipment base is able to reduce the factor of safety about 10%. Therefore, the adequate method for evaluating of effective height of side wall is required as further study.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.167-167
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• 2017

• Smart Structures and Systems
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• v.9 no.6
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• pp.489-504
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• 2012

For the safety of prestressed structures such as cable-stayed bridges and prestressed concrete bridges, it is very important to ensure the prestress force of cable or tendon. The loss of prestress force could significantly reduce load carrying capacity of the structure and even result in structural collapse. The objective of this study is to present a smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection. Firstly, a smart PZT-interface is newly designed for sensitively monitoring of electro-mechanical impedance changes in tendon-anchorage subsystem. To analyze the effect of prestress force, an analytical model of tendon-anchorage is described regarding to the relationship between prestress force and structural parameters of the anchorage contact region. Based on the analytical model, an impedance-based method for monitoring of prestress-loss is conducted using the impedance-sensitive PZT-interface. Secondly, wireless impedance sensor node working on Imote2 platforms, which is interacted with the smart PZT-interface, is outlined. Finally, experiment on a lab-scale tendon-anchorage of a prestressed concrete girder is conducted to evaluate the performance of the smart PZT-interface along with the wireless impedance sensor node on prestress-loss detection. Frequency shift and cross correlation deviation of impedance signature are utilized to estimate impedance variation due to prestress-loss.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.180-180
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• 2017

• Journal of Navigation and Port Research
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• v.42 no.3
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• pp.201-206
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• 2018

The purpose of this study is to estimate a proper Domain Watch between anchored vessels in order to propose a method for the efficient management of VTS(Vessel Traffic Service) of the N-anchorage in Busan harbor, which is the largest port in Korea. For this purpose, we proposed the calculation method of Domain Watch and investigated the ship length(L), the distance between anchored vessels ($D_{ij}$), the domain radius(R), and the domain radius vs L(R/L) during the peak time of the vessels in the latest usage of anchorage. As a result of technical analysis for the surveyed data, the minimum R/L for securing the safety distance between anchored vessels was selected based on 2.85 corresponding to the 70th percentile of the total data. This result was applied to the N-anchorage of Busan and compared with the 'Guidelines of Port and Harbor Design(2014)', and we have confirmed that it is reasonable to set the Domain radius with the minimum 2.85L or more in VTS. This study considers the safety management of anchorage for VTS. This study could contribute to the safety of vessels using anchorage and the safety management plan of VTS when it is applied to other ports in operation such as it was in Busan.

• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.49-53
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• 2013

This paper describes the assessment of seismic performance of the concrete gravity dam seismically reinforced by post-tensioned anchors. In order to evaluate the seismic performance, the response spectrum analyses have been carried out for 7 different configurations of the post-tensioned anchors, and then their performance improvement in the maximum tensile and compressive stresses is compared to each other. The comparative results demonstrate that the layout of the post-tensioned anchors strongly influences the seismic performance of the concrete gravity dam. In this study, the slightly-inclined vertical anchorage system shows the largest improvement on the overall performance of the seismically-excited concrete gravity dam.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.485-497
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• 2024

Ring beam is the main anchorage zone of the tendons in the nuclear power prestressed concrete containment vessel (PCCV). Its safety is crucial and has a great influence on the overall performance of PCCV. In this paper, two half-scale ring beams were tested to investigate the mechanical performance of the anchorage zone in the PCCV under multidirectional pressure. The effect of working condition with different tension sequences was investigated. Additionally, a half axisymmetric plane model of the containment was established by the finite element simulation to further predict the experimental responses and propose the local reinforcement design in the anchorage zone of the ring beam. The results showed that the ultimate load of the specimens under both working conditions was greater than the nominal ultimate tensile force. The original reinforcement design could meet the bearing capacity requirements, but there was still room for optimization. The ring beam was generally under pressure in the anchorage area, while the splitting force appeared in the under-anchor area, and the spalling force appeared in the corner area of the tooth block, which could be targeted for local strengthening design.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.663-670
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• 2014

The Pyeongtaek port is expected lack of waiting anchorage due to increase of incoming ships whit increasing of trading volume in the near future. In case of an anchorage facility's structural alternations and expansion, it should be considered comprehensively how it affects other anchorage facilities. In addition, the volume of ship traffic to relevant area should be estimated accurately and then the facility's scale is calculated. In this paper, researchers calculated cargo per unit ship with the throughput for every ship and predicted the number of ships which had entered Pyeongtaek port. As a result, the port's ability to be docked was predicted to be not enough in 2030. It will exceed the number of ships able to cast anchor at specific two parts simultaneously 12.6 and 1.6 respectively consequently, the necessity to expand the ports was suggested. Hence, the best expansion plan was examined with analysis of marine transportation environment at each ports and the improvements suggested are anchoring ships at Ippado anchorage is 19.7 and the one at Janganseo anchorage is 12.6.