• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.827-832
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• 2001

Shrinkage during the curing and drying of concrete is unavoidable and results in many cracks. Shrinkage strips reduce effectively shrinkage stresses and minimize shrinkage cracks by being left open for a certain time during construction to allow a significant part of the shrinkage to occur without inducing stresses. This study verifies the effectiveness of shrinkage strips and provides the guide for construction of such strips.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.263-265
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• 2003

The transverse crack, a type of cold crack, occurs perpendicular to the axis of the weld interface, longitudinal residual stresses ($\sigma$k direction) are more important in transverse crack occurrence from my own experience. Specimens were fabricated and welded under actual construction conditions, and then residual stresses of longitudinal stresses were measured for different welding conditions with SAW and FCAW process. The residual stress values for the specimen welded Interpass temperature below 30$^{\circ}C$ was higher than the specimen welded interpass temperature of 100～120$^{\circ}C$. And also the residual stress values for a specimen measured at weld surface, as welded condition, was higher than that of longitudinal residual stresses that was measured from a small test piece, due to the residual stress was relieved in the process of the cutting and machining. Transverse weld cracks were detected in the area of the maximum residual stresses both SAW and FCAW process.

• Structural Engineering and Mechanics
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• 제58권5호
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• pp.783-797
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• 2016

Exact solutions for stresses, strains, and displacements of a perforated rectangular plate by an arbitrarily located circular hole subjected to both linearly varying in-plane normal stresses on the two opposite edges and in-plane shear stresses are investigated using the Airy stress function. The hoop stress occurring at the edge of the non-central circular hole are computed and plotted. Stress concentration factors (the maximum non-dimensional hoop stresses) depending on the location and size of the non-central circular hole and the loading condition are tabularized.

• 대한조선학회지
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• 제13권1호
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• pp.25-34
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• 1976

Analytical solutions for the transient temperature and quasi-static thermal stresses which arise in thin plates subjected to an instantaneous point source of heat have been investigated. And the solutions have been extended to the case of a moving source of heat with the aid of the Duhamel's superposition integral. For finite disk an experiment was conducted, the measured temperature histories show a good agreement with the theoretical temperature histories, And the histories of thermal stresses show a good qualitative agreement with the physical phenomena. And also we can find out that the maximum temperature and thermal stresses and their location can be estimated by using the solutions for infinite plates instead of the solutions for a finite plate. The solutions can be used for the problems such as a welding or line heating in a hull construction.

• Computers and Concrete
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• 제13권4호
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• pp.483-499
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• 2014

Most of the methods presented in the literature to define the target service stresses (Objective Service Stage, OSS) of cable-stayed bridges rarely include the time-dependent phenomena effects. Nevertheless, especially in concrete structures, this assumption might be on the unsafe side because time-dependent phenomena usually modify service stresses. To fill this gap, this paper studies the time-dependent phenomena effects into service stresses of concrete cable-stayed bridges. After illustrating the important role of these phenomena in an asymmetrical cable-stayed bridge without backstay, a new method to include their effects into the OSS is presented. An important issue to be considered in this method is the target time in which the OSS is defined to be achieved. The application of this method to two different structures showed the convenience of defining the OSS to be achieved at early times because that way the envelope of service stresses is reduced.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5956-5963
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• 2013

친환경 하천사업의 활성화로 식생매트의 사용은 증가하고 있으나 수리적 안정성에 대한 평가기법은 제시되지 않은 실정이다. 본 연구는 호안용 식생매트 제품의 객관적인 수리안정성 시험 기법 개발을 위해 수행하였다. 이를 위해서 식생매트 2종에 대한 실규모 실험을 수행하여 수리량을 측정하고 분석하여 작용 소류력을 계산하였다. 작용 소류력에 대한 토양손실평가를 위하여 지상라이다에 의한 측량을 수행하고 실험 전후의 하상고 변화를 평가하여 토양손실지수(CSLI)를 산정하였으며, 작용 소류력과 함께 도시하여 허용 소류력을 정량적으로 평가하였다. 하상고에 대한 정밀 측량 결과 분석에 의해서 식생매트가 안정한 경우에는 하상 변동이 국부적으로 제한되나, 불안정으로 판정되는 경우에는 식생매트 하부에서 비교적 큰 규모의 하상 변동이 발생하며 이는 자연 하상의 거동과 유사함을 확인하였다. 이상의 연구를 통해서 ASTM D 6040에 의한 식생매트의 허용 소류력 평가가 파괴 메카니즘 및 토양손실판정 기준에서 유효함을 확인할 수 있었다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.212-214
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• 2004

It is widely recognized that the residual stress of weldment affects steel construction and causes fracture initiation of welded structures. It is necessary to know since the power plants adopt a variety of welding processes distribution and magnitude of residual stresses. Therefore the purpose of present study is to investigate the validity of the indentation method to measure residual stresses of steel plates by residual stresses measured form the specimens of hot reheater pipes, cold reheater pipes and feed water lines used in power plants.

• Steel and Composite Structures
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• 제35권2호
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• pp.279-294
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• 2020

Foundation of a building is damaged under service loads during construction. First visit shows that the foundation has been punched at the 6 column's foot region led to building rotation. Foundation shear punching occurring has made some stresses and deflections in construction. In this study, progressing of damage caused by foundation shear punching and inverse loading in order to resolve the building rotation has been evaluated in the foundation and frame of building by finite element modeling in ABAQUS software. The stress values of bars in punched regions of foundation has been deeply exceeded from steel yielding strength and experienced large displacement based on software's results. On the other hand, the values of created stresses in the frame are not too big to make serious damage. In the beams and columns of ground floor, some partial cracks has been occurred and in other floors, the values of stresses are in the elastic zone of materials. Finally, by inverse loading to the frame, the horizontal displacement of floors has been resolved and the values of stresses in frame has been significantly reduced.

• Earthquakes and Structures
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• 제23권2호
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• pp.183-196
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• 2022

Reduced beam section (RBS) moment connections used in special moment resisting frames are currently limited to beam sections that are not larger than nominal depths of 920 mm, weight of 447 kg/m and flange thickness of 44 mm. Due to the higher demand for structural components with jumbo sections, which can potentially be applied in the transfer girders in long-span building structures, the newly available steel heavy members are promising. To address this issue, advanced numerical models are developed to fully evaluate the distribution of stresses and concentrations of plastic strains for such jumbo RBS connections. This paper first presents a brief overview of an experimental study on four specimens with large beam and column sections. Then, a numerical model that includes initial imperfections, residual stresses, geometric nonlinearity, and explicitly modeled welds is presented. The model is used to further explore the behavior of the test specimens, including distribution of stresses, distribution of plastic strains, stress triaxiality and potential for fracture. The results reveal that the stresses are highly non-uniform across the beam flange and, similarly, the plastic strains concentrate at the extreme fiber of the bottom flange. However, neither of these phenomena, which are primarily a function of beam flange thickness, is reflected in current design procedures.

• Coupled systems mechanics
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• 제13권3호
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• pp.247-275
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• 2024

The paper studies the influence of the fluid flow velocity and flow direction in the initial state on the dispersion of the axisymmetric waves propagating in the inhomogeneously pre-stressed hollow cylinder containing this fluid. The corresponding eigenvalue problem is formulated within the scope of the three-dimensional linearized theory of elastic waves in bodies with initial stresses, and with linearized Euler equations for the inviscid compressible fluid. The discrete-analytical solution method is employed, and analytical expressions of the sought values are derived from the solution to the corresponding field equations by employing the discrete-analytical method. The dispersion equation is obtained using these expressions and boundary and related compatibility conditions. Numerical results related to the action of the fluid flow velocity and flow direction on the influence of the inhomogeneous initial stresses on the dispersion curves in the zeroth and first modes are presented and discussed. As a result of the analyses of the numerical results, it is established how the fluid flow velocity and flow direction act on the magnitude of the influence of the initial inhomogeneous stresses on the wave propagation velocity in the cylinder containing the fluid.