• International Journal of Highway Engineering
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• v.10 no.4
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• pp.257-267
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• 2008

This study was conducted to investigate the stress distribution in the prestressed concrete pavement (PSCP) when the transverse post tensioning was applied. By performing the structural analyses using a finite element model of PSCP, the effect of anchor spacing and the relationship between the longitudinal and transverse post tensioning were evaluated. The analysis results showed that as the anchor spacing became smaller, the stresses were more uniformly distributed and the ranges of the stress losses were reduced; however, the economy should be considered. As the anchor spacing became larger, the difference between the average transverse stress and the transverse stresses at various locations such as shoulder, wheel pass, and center of the slab, increased. The transverse post tensioning induced the additional tensile forces in the longitudinal tendons, but the magnitude was negligibly small, and the longitudinal and transverse post tensioning could be designed independently. The use of the transverse stress distribution for the design of the post tensioning was also discussed in this paper.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.269-279
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• 2008

This study was conducted to develop the design methodology of transverse post-tensioning for the prestressed concrete pavement (PSCP). The transverse stress distribution was analyzed when the transverse anchor spacing changed. The tensile stress distribution in the PSCP slab due to the environmental and vehicle loads was also investigated. The reasonable methods were discussed to determine the design loads including environmental and vehicle loads and the PSCP allowable tensile stress used for the basis of the selection of the stress application amount from the tensioning. The results of this study showed that as the transverse anchor spacing increased, the range of the stress loss became larger and the stress loss was significant near the shoulder. The design of the transverse post-tensioning can be performed by obtaining the stresses under the design loads and by considering the allowable tensile stress; however, the tensile stresses at different locations such as the shoulder, wheel pass, and slab interior should also be checked and kept below the allowable tensile stress.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.407-412
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• 1999

본 연구에서는 향이 자율신경계에 미치는 영향을 알아보고자 100%의 Rose oil bulgarian, Lemon oil misitano, Jasmin abs., Lavender oil france (KIMEX co. Ltd)의 네가지 향을 사용하여 심전도, 피부온도, 피부저항의 생리신호를 측정하였고, 생리신호의 측정과 함께 주관적 설문지의 평가를 통해 생리신호와의 상관성을 살펴보았다. 주관적 평가 중 양극 척도의 긴장/이완에 해당되는 문항의 분석결과 장미>자스민>레몬>라벤더 순으로 피험자들에 의해 장미가 가장 긴장된다는 결과를 나타냈다. 향의 선호도 조사에서는 장미향이 가장 진한 향으로 레몬 향이 가장 좋은 향으로 분석결과가 나왔다. 생리신호 중 평균 R-R 간격의 측정 결과는 장미향에서 가장 긴장도가 높게 나타났으며 이에 따른 주관적 평가 결과 역시 장미향이 긴장도가 높게 나와 생리신호와 주관적 평가의 결과가 상관성을 가지고 있음을 알 수 있었고, 피부온도 결과에서는 평균 R-R 간격에서 긴장도가 가장 높은 장미가 피부온도가 가장 높게 나왔다. 피부저항은 레몬 향이 가장 긴장된 것으로 나온 반면 라벤더가 가장 이완으로 나타났으며 라벤더의 경우 주관적 평가와의 상관성을 가짐을 알 수 있었다. 이와 같이 향이 자율신경계에 미치는 영향을 알아보고자 주관적 평가와 생리신호를 동시에 측정하였는데 그 결과 주관적 평가와 생리신호의 상관성을 통해 향이 자율신경계에 어떤 영향을 미치는가를 알 수가 있었다.

• Tunnel and Underground Space
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• v.19 no.5
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• pp.388-396
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• 2009

Rock bolt is one of the most important supports for tunnelling to prevent excessive ground relaxation at the primary tunnel excavation stage. It forms a ground arch band by confining the ground around a tunnel. Rock bolt has various effects, such as support or hanging effect, internal pressure effect, arching effect, ground improvement effect etc. Most studies on rock bolt focused on the concept of support, but only a few researches on the ground reinforcing effect by pre-tensioning a rock bolts. In this study, large scale model tests are performed to investigate the ground reinforcing effect of rock bolts for regularly jointed rocks. Simple beam model was built to find out the reinforcing effect of jointed rocks, which was reinforced by pre-tensioned rock bolts. Settlement of model beam was analyzed through measuring its sagging for various installation intervals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.587-596
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• 2009

This study analyzes the lateral distribution behavior of external post-tensioning force and evaluates the possibility of strengthening the servicing composite girder bridge by adopting the external post-tensioning force to the parts of the bridge girder. From the results of experiments and analyses, it is founded that the composite girder bridge can be strengthened by applying the external post-tensioning force to the parts of the bridge girder. It is also proved that bracing improve the lateral distribution behavior of post-tensioning force. The lateral distribution behavior of post-tensioning force which influenced by stiffness ratio, girder spacing and span length is changed by the bridge type and the location of tensioned girder. From the results of analyses, set up an equation which can predict the lateral distribution behavior of external post-tensioning force and evaluate the rationality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.362-370
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• 2019

The internal pressure capacity of a modular containment structure requires analysis to prevent the release of radioactive material in the case of an accident. To analyze the capacity, FEM models were prepared while considering the tendon arrangements and the contact surfaces between precast concrete modules, and then static analyses were carried out. The changing characteristics in the displacement and stress under step-wise loading were analyzed, along with the effects of selected parameters. For comparison, the capacity of a monolithic containment structure was also analyzed. Parametric analyses were done to suggest ranges of parameters such as the tendon force, tendon spacing, tendon location in concrete thickness direction, friction coefficient, and concrete thickness. The tendon force and frictional force provide a combined effect between contact surfaces of modules. The same level of internal pressure capacity can be secured even in the modular containment structure as in the monolithic containment structure by increasing the tendon force with additional tendons.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.329-336
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• 2010

An experimental study to evaluate bursting behavior in anchorage zone of the standard PSC I girders (span length : 30 m) has been carried out. The arrangement of bursting reinforcement in anchorage zone of the standard PSC I girders is considered to be designed without accurately reflecting the stress flows in the end zone of the PSC I girders caused by presstressing forces of the tendons. Also, due to excessive arrangement of the bursting bars, the workability of the girder is decreased greatly. In this study, three specimens with the same dimensions as the end zone of the standard PSC I girder are prepared and the experiment is carried out by applying PS forces. The bursting reinforcement of each specimen consists of 100 mm, 200 mm, and 300mm spacings, respectively. The experimental results show that the range of the PS forces to cause crack in the anchorage zone of the specimen are more than 1.6 times of the design PS forces. The bursting cracks occur in the vertical direction on the inside of all specimens. After applying 2.7 times of the design PS force, some of the transverse bursting reinforcements only in the specimen reinforced by 300 mm spacing yielded. The experimental results show that the anchorage zone of the standard PSC I girders arranged by 300 mm spacing of the bursting reinforcements which is the maximum spacing allowed in the road bridge design specifications, can be considered safe enough.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.203-215
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• 2009

This study was conducted to develop the design methodology of longitudinal post tensioning for the post-tensioned concrete pavement (PTCP). The longitudinal stress distribution in the PTCP slab was analyzed when post tensioning was applied. Then, the tensile stress distribution in the PTCP slab due to the environmental and vehicle loads needed for the design was investigated. In addition, prestress losses were calculated considering the losses due to the frictional resistance between the slab and underlying layer and due to various reasons related to tensioning. The tensile stresses used for the design were obtained by adding the stresses from the critical conditions under both the environmental and vehicle loads. The prestress losses were obtained by considering actual field conditions. The effective post tensioning amount was determined by considering the design loads including environmental and vehicle loads and various losses, and the effect of the allowable tensile stress on the post tensioning amount was investigated. The initial stage of the design of the longitudinal post tensioning is to obtain the stresses under the design loads and the required prestress determined by subtracting the allowable tensile stress from the design stress. Then, the optimal tendon spacing and the tensioning amount can be obtained by comparing with the effective tensioning amount including various stress losses.

• Proceedings of the KSLP Conference
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• 1994.06b
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• pp.82-82
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• 1994

다양한 성대의 진동 형태와 조절 작용을 연구하기 위해서 실시간에서 움직이는 인공성대를 만들어 모델의 타당성을 검토하고 이를 이용하여 생리적 음성과 병적인 음성의 기전을 밝히는 것이 본 연구의 목적이다. 지금까지 연구되어온 정적 모델이나 후두절개 표본의 단점과 한계를 극복할 수 있는 모델을 제작하기 위해 고려해야 할 점은 모델을 이용한 성대 진동 파형의 수평적 수직적 요소의 관찰이 용이해야 하고 성대진동의 기본 요소들 즉 성대의 긴장도, 성문간격, 성문하압 등의 변화에 따른 음성 발현 양상의 차이를 쉽게 보여줄 수 있는 지에 관한 것이다. (중략)

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.11a
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• pp.227-232
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• 1999

본 논문은 음악 리듬의 비트간의 간격의 변화가 사람의 심박동 및 쾌적감에 미치는 영향을 평가하기 위하여 음악 리듬의 박자를 규칙적인 다섯 단계의 변화를 적용하여 평가했다. 평가 항목으로는 (1) LF성분에 많은 영향을 보이는 심박동의 전력스펙트럼 분석과 (2) S.D.법으로 심리적 평가항목을 수행하였다. 실험 결과는, 박자의 변동이 일정한 정박자 리듬에서는 생체에 특이한 변화가 나타나지 않았지만 박자의 변동이 변화하는 리듬에서는 LF성분이 증가함으로 긴장과 불안이 유발됨을 알 수 있었다. 추가적으로 심박변동의 스펙트럼 분석를 통하여 얻을 수 있는 LF와 HF 성분사이의 비를 조사함으로 심리학적 불안을 평가하는 가능성을 제안한다.