• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.189-195
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• 2002

The differential quadrature method (DQM) is applied to computation of the eigenvalues of out-of-plane bucking of curved beams. Critical moments including the effect of radial stresses are calculated for a single-span wide-flange beam subjected to equal and opposite in-plane bending moments with various end conditions, and opening angles. Results are compared with existing exact solutions where available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used. New results are given for two sets of boundary conditions not previously considered for this problem: clamped-clamped and clamped-simply supported ends.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.81-89
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• 2003

The simple supported reinforced concrete slab bridges are analyzed by the specially orthotropic laminates theory. This method, however, may be too difficult for some practising engineers. In this paper, the result of analysis for such plate by means of the beam theory with unit width is reported. By using the "correction factor", the accurate solution for the plate can be obtained by the beam theory. The result of this paper can be used for reinforced concrete slab bridges analysis by the engineers with undergraduate study in near future.

• The Korean Journal of Coaching Psychology
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• v.6 no.2
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• pp.75-92
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• 2022

There are many studies that intrinsic learning motivation and social support play an important role in the study of children and adolescents. However, studies examining the effects of intrinsic learning motivation and social support by measuring the actual academic performance of elementary school students are rare. This study attempted to verify the effect of intrinsic learning motivation on Korean language performance and moderating effect of social support in 5th and 6th graders in elementary school. 122 elementary school students in local county-level areas participated in this study. The Korean language test was conducted about 5 months after intrinsic learning motivation and social support of families and teachers were measured. The results revealed that Korean language performance showed a significant positive correlation with intrinsic learning motivation and social support, and also showed a significant correlation between learning motivation and social support. In the regression analysis with control variables, it was found that intrinsic learning motivation had a significant effect on Korean language performance. The moderating effect of social support was analyzed by dividing it into family support and teacher support. The interaction effect of learning motivation and social support was significant only in teacher support, not in family support. In specific, when teacher support was high, Korean language performance was high regardless of the student's learning motivation level, but when teacher support was low, the student's learning motivation mattered in the performance. Based on the results of this study, implications and limitations were discussed.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.18-26
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• 2004

The cost of underground work is a dominant factor to determine the total construction fee. It is generally 2 ${\~}$ 2.5 times higher than that of above ground for building with the same height. 'A new precast prestressed framing plan for underground parking building' was suggested with the beam of the least depth - U-type beams. The depth of regular rectangular reinforced concrete beam which is currently used in the underground parking of apartments could be reduced up to 12 ${\~}$ 34cm/story due to the development of a U-beams from the optimum process. Two full scale prototype U-beams were tested in this study. It was found that the Wide U-beams in the test showed higher strength than calculated nominal and design, however need to provide temporary supports to meet the flexural moment of construction load at the simply supported state before the lopping concrete hardens.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.847-850
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• 2008

In simply supported concrete beams with concentrated load, there is arch action that the internal lever arm length varies through shear span. Recently shear analysis model considering this effect has been developed, but the analysis algorithm is so complicated. Moreover, the variation of internal lever arm length is not considered on the shear compatibility condition. In this study, the shear analysis model is developed more simply and the variation of internal lever arm length is considered on the shear compatibility condition. From these modifications, an actual shear behavior of RC beams subjected to concentrated load could be expected from the results of the proposed analysis model.

• Composites Research
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• v.12 no.4
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• pp.33-41
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• 1999

In this paper, a simple but accurate method of vibration analysis of structural elements with or without attached mass/masses is presented. The method used has been developed by D.H., Kim since 1974. This method is very effective for the plates with arbitrary conditions and irregular sections. This method is applied to the special orthotropic plate with two opposite edges simply supported and the other two opposite edges free. Such plate represents the most of the simply supported bridges/decks, including concrete and girders-cross beam systems. Detailed illustration is given for beams and plates for easy understanding. Some laminate orientation for which the special orthotropic equations can be applied are identified.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.27-38
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• 2016

The purpose of this study is to investigate the influence of moving mass on the vibration characteristics and the dynamic response of the simply supported beam. The three types of the moving mass(moving load, unsprung mass, and sprung mass) are applied to the vehicle-bridge interaction analysis. The numerical analyses are then conducted to evaluate the effect of the mass, spring and damper properties of the moving mass on natural frequencies and dynamic responses of the simply supported beam. Particularly, in the case of the sprung mass, variations of the natural frequency of simply supported beam are explored depending on the position of the moving mass and the frequency ratio of the moving mass and the beam. Finally the parametric studies on the resonance phenomena are performed with changing mass, spring and damper parameters through the dynamic interaction analyses.

• Fire Science and Engineering
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• v.23 no.2
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• pp.27-35
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• 2009

In this study, the fire resistance performance of a simple support composite beam, which was sprayed with fire protection coatings, was evaluated. Primary valuables of the study are loading and unloading, shape of composite beam and metal lath of the web. The thickness of the fire protection coating to the three hour resistance is 40mm, but the fire resistance test was performed with 25mm coatings. The test result showed that TSC composit beams with 25mm fire protection coatings can resist on fire for three hours at the both loading and unloading tests. Average and maximum temperatures were less than $250^{\circ}C$ and $310^{\circ}C$ respectively, compared with the standard temperatures for fire resistance on the loading and unloading tests.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.735-742
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• 2006

In this study, the ultimate shear strength behavior of transversely stiffened curved web panels was investigated through nonlinear finite element analysis. It was found that if the transverse stiffener has a sufficient rigidity, then curved web panels used in practical designs are able to develop the postbuckling strength that is equivalent to that of straight girder web panels having the same dimensional and material properties. The nonlinear analysis results indicate that in order for curved web panels to develop the potential postbuckling strength. The rigidity of the transverse stiffener needs to be increased several times the value obtained from the Guide Specifications (AASHTO, 2003). However, in the case of thick web panels where the shear design is governed by shear yielding, the stiffener rigidity does not have to be increased. From the analysis results, a simple design formula is suggested for the rigidity of transverse stiffener under strength limit state.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.25-35
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• 2000

The superstructure of general bridge like slab bridge and slab on girder bridge is composed of elastically supported isotropic plate. The objective of this study is to develop the new analysis method for elastically supported plate with general edge beam or girder(boundaries) under arbitrary out of plane loading. The displacement solutions for the macro-element of plate and beam are obtained by solving for the unknown interactive forces and moments at the beam or nodal line locations after satisfying equilibrium equation along the nodal line. The displacement functions for macro-elements ate proposed in single Fourier series using harmonic analysis, and the equilibrium equations of nodal line are composed by using slope-deflection method. The proposed analysis method is programmed by MS-Fortran and can be applied to all types of isotropic decks with bridge-type boundaries. Numerical examples involving elastically supported plates with various aspect ratio, loading cases, and bridge-type boundary conditions are presented to demonstrate the accuracy of this program. The major advantage of this new analysis method is the development of a simple solution algorithm, leads to obtain rapidly responses of bridge deck system. This proposed method can be used in parametric study of behavior of bridge decks.