• 대한조선학회논문집
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• 제44권5호
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• pp.504-508
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• 2007

In the case of thin plate blocks, buckling deformation due to longitudinal shrinkage is the most important weld-induced deformation. This paper is concerned with developing the formula to predict the longitudinal shrinkage due to welding, in which mechanical tension effect in welding direction is accounted for. For this purpose, bead on plate welding test has been carried out for the 27 thin plate specimens with varying welding conditions and magnitude of tensile load. Empirical formula of predicting the longitudinal shrinkage has been derived based on the results of welding test, in which effect of mechanical tension is included. The derived formula can be usefully used in predicting the level of tensile load to reduce the longitudinal shrinkage.

• Smart Structures and Systems
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• 제4권6호
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• pp.711-726
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• 2008

A number of efforts had been sought to instrument bridges for the purpose of structural monitoring and assessment. The outcome of these efforts, as gauged by advances in the understanding of the definition of structural damage and their role in sensor selection as well as in the design of cost and data-effective monitoring systems, has itself been difficult to assess. The authors' experience with the design, calibration, and operation of a monitoring system for the Kishwaukee Bridge in Illinois has provided several lessons that bear upon these concerns. The systems have performed well in providing a continuous, low-cost monitoring platform for bridge engineers with immediate relevant information.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1044-1047
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• 2004

This aim of this study is is an experimental study to introduce the Reduction method of Floor Impact Sound in Apartment Houses by using Model Test, We are measured the floor impact sound in Rahamen and Apartment with Shear Wall and Post-tensioning. There is comparison between Rahmen Structure and Apartment with Shear Wall. The main results from this study are effective in reduction of heavt-weight The slab was constructed by rahamen structure. Heavy-weight can reduced by upgrading naturial frequency of floor impact sound in rahmen structure.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.672-680
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• 2005

There are a lot of reasons to use In-place tests. Construction schedules often require that operations such as form removal, post-tensioning, termination of curing, and removal of reshores be carried out as early as possible. To enable these operations to proceed safely as soon as possible requires the use of reliable in-place tests to estimate the in-place strength. In-place test results are not reliable for engineering judgment. These results should be interpreted and correlated to standard compressive strength, based on the test method. In this paper some of these test procedures and their limitations are discussed. In this study we will go on for Rebound number, Pullout, Ultrasonic pulse velocity, and Cast-in-place cylinder methods which are most useful methods in the Asia.

• Wind and Structures
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• 제34권3호
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• pp.313-319
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• 2022

The resiliency of electricity transmission and distribution lines towards natural and man-made hazards is critical to the operation of cities and businesses. The extension of these lines throughout the country increases their risk of extreme loading conditions. This paper investigates a unique extreme loading condition of a 100-year old distribution line segment that passes across a river and got entangled with a boom of a ship. The study adopts the Applied Elements Method (AEM) for simulating 54 cases of the highly deformable structural behaviour of the tower. The most significant effects on the tower's structural integrity were found to occur when applying the load with components in all three of the cartesian directions (i.e., X, Y and Z) with the full capacities of the four cables. The studied extreme loading condition was determined to be within the tower's structural capacity, attributed to the shear failure of the anchor bolts, which acted as a sacrificing element that fails to protect the transfer of tensioning load to the supporting tower.

• 한국강구조학회 논문집
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• 제23권4호
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• pp.429-438
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• 2011

본 연구에서는 스트라치 시스템의 긴장설치과정 및 극한하중 해석을 수행하기 위한 명시적 해석법을 제안하였다. 스트라치 시스템은 Stressed-Arch에서 유래한 용어로 슬리브와 갭이 도입된 유동하현재 내부의 긴장재에 초기장력을 도입함으로써 갭이 점차 닫히게 되며, 이에 따라 상현재에 곡률이 도입되면서 전체 구조물이 상승하여, 최종적인 아치형태의 구조물을 형성하는 독창적인 구조시스템이다. 스트라치 시스템의 초기장력 도입과정을 긴장설치(stress-erection) 과정이라 하며, 초기곡률의 도입에 따라 유동 상현재에는 과도한 초기변형이 발생하여 소성거동에 의한 강체회전이 발생하는 불안정 구조물이 된다. 본 연구에서는 이러한 스트라치 시스템의 불안정 거동특성을 해석하기 위해서 강성행렬을 사용하지 않는 명시적 동적이완법을 사용하여 비선형 평형방정식의 해를 구하였고, 대변위 및 단면의 재료적 특성을 반영할 수 있는 필라맨트 보요소를 사용하여 연속된 상현재의 비선형 거동특성을 분석하였다. 필라맨트 보요소의 단면은 다수의 1차원 필라맨트로 구성되며, 각각의 필라맨트에 대해서 다양한 재료모델을 적용할 수 있다. 본 연구에서는 비선형 재료모델인 Ramberg-Osgood모델 및 Bi-linear 탄소성 모델을 적용하여 긴장설치 및 극한하중 해석을 수행하였고, 그 결과를 이전의 실험적 연구결과와 비교 분석하였다. 본 연구의 해석결과는 이전의 실험적 연구결과와 유사하였으며, 명시적 해석법의 특성상 효율적으로 후좌굴거동 특성까지 해석할 수 있었다.

• 대한토목학회논문집
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• 제14권6호
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• pp.1309-1317
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• 1994

앵커리지 (Anchorage)가 주케이블을 지지하는 전형적인 현수교에서는 행거를 가설한 후에 보강형을 순차적으로 가설하기 때문에 시공시 행거에 별도의 긴장력이 필요없다. 이와는 달리 자정식 현수교는 가교각으로 보강형을 지지한 후 행거를 설치하게 된다. 따라서 행거 가설시 초기 긴장력을 가할 필요가 있으며 이 후 계속되는 시공과정에 의해 장력이 지속적으로 변화하게 된다. 따라서 행거의 가설방법을 변화시켜가며 이에 따른 행거장력의 변화 양상을 파악하여 가장 효율적으로 행거를 가설할 수 있는 방법을 결정할 필요가 있다. 이를 위하여 본 연구에서는 해석적인 방법을 제시하였다. 현수교 시공의 진행에 따라 단계적으로 변화하는 구조계를 모사할 수 있는 사공단계해석 알고리즘을 제시하였다. 또한 자정식 현수교에서 발생할 수 있는 기하비선형 해석모델을 제시하였다. 실물 교량을 대상으로 제시된 해석방법에 따라 가장 효과적이라고 생각되는 시공방법을 제시하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제17권4호
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• pp.48-56
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• 2013

프리텐션 방식을 사용한 PSC 휨부재는 시공이 간편하고 품질관리가 용이하기 때문에 최근 토목분야에서 적용된 사례가 증가하고 있다. 특히, PSC 휨부재의 종류 중 하나인 반단면 프리캐스트 콘크리트 합성 슬래브는 롱라인 공법을 적용하여 최근에 개발되었다. 반단면 프리캐스트 콘크리트 합성 슬래브는 프리캐스트 콘크리트와 현장타설 콘크리트를 합성하여 제작한다. 이 연구에서는 롱라인 공법으로 제작한 프리캐스트 PSC를 적용한 반단면 프리캐스트 콘크리트 합성 슬래브의 프리스트레스 도입 효율과 휨강도에 대한 실험을 실시하고 그 결과를 제시하였다. 롱라인 공법은 한번의 긴장력 도입으로 여러 개의 부재를 생산할 수 있는 장점이 있다. 또한, 프리캐스트 PSC 내에 매입되어 있는 철근의 영향을 고려하여 반단면 프리캐스트 콘크리트 합성 슬래브의 휨강도를 합리적으로 평가할 수 있는 식을 제시하였다.

• Computers and Concrete
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• 제31권4호
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• pp.337-348
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• 2023

Shear wall is commonly used as a lateral force resisting system of concrete mid-rise and high-rise buildings, but it brings challenges in providing relatively large space throughout the building height. For this reason, the structure system where the upper structure with bearing, non-bearing and/or shear walls that sits on top of a transfer plate system supported by widely spaced columns at the lower stories is preferred in some regions, particularly in low to moderate seismic regions in Asia. A thick reinforced concrete (RC) plate has often been used as a transfer system, along with RC transfer girders; however, the RC plate becomes very thick for tall buildings. Applying the post-tensioning (PT) technique to RC plates can effectively reduce the thickness and reinforcement as an economical design method. Currently, a simplified model is used for numerical modeling of PT transfer plate, which does not consider the interaction of the plate and the upper structure. To observe the actual behavior of PT transfer plate under seismic loads, it is necessary to model whole parts of the structure and tendons to precisely include the interaction and the secondary effect of PT tendons in the results. This research evaluated the seismic behavior of shear wall-type residential buildings with PT transfer plates for the condition that PT tendons are included or excluded in the modeling. Three-dimensional finite element models were developed, which includes prestressing tendon elements, and response spectrum analyses were carried out to evaluate seismic forces. Two buildings with flat-shape and L-shape plans were considered, and design forces of shear walls and transfer columns for a system with and without PT tendons were compared. The results showed that, in some cases, excluding PT tendons from the model leads to an unrealistic estimation of the demands for shear walls sit on transfer plate and transfer columns due to excluding the secondary effect of PT tendons. Based on the results, generally, the secondary effect reduces shear force demand and axial-flexural demands of transfer columns but increases the shear force demand of shear walls. The results of this study suggested that, in addition to the effect of PT on the resistance of transfer plate, it is necessary to include PT tendons in the modeling to consider its effect on force demand.

• 한국공간구조학회논문집
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• 제14권3호
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• pp.85-92
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• 2014

Most of the structural forms in which ETFE film is used are the cushion(pneumatic membrane structures) and tension type(tensile membrane structures), which have been generally accepted to be the most efficient forms. Tensile membrane structures are pulled outward from the exterior to introduce initial stress. And such structures offer the advantage of a natural shape formed by tensile stress and eliminate the need for blast air. Recently, the number of tension type structures is increasing. However, there are problems of creep and relaxation of ETFE films under long-term stresses. In this paper, the stretch fabrication method is proposed for stretching the film into the plastic region during initial tensioning as a way to increase its strength. And its effectiveness is confirmed by investigating experimental and analytical test using ETFE films.