• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.6
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• pp.570-579
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• 2011

This paper deals with free vibrations of the circular curved beams with constant volume, whose cross sectional shapes are the circular solid cross-sections. Volumes of the objective beam are always held in constant regardless shape functions of the cross-sectional radius. The shape functions are chosen as the linear, parabolic and sinusoidal ones. Ordinary differential equations governing free vibrations of such beam are derived and solved numerically for determining the natural frequencies. In numerical examples, the hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, relationships between frequency parameters and various beam parameters such as rise ratio, section ratio, elasticity ratio, volume ratio, slenderness ratio and taper type are reported in tables and figures.

• Journal of the Korean Geotechnical Society
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• v.36 no.1
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• pp.29-38
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• 2020

These days the circular cross section cofferdam has been frequently used for the earth retaining structures or cut off wall such as ventilating opening, intake tower in cofferdam, shaft for emergency. By the arching effect, the circular cross section type cofferdam has more advantage than a polygon cofferdam in terms of the structural forces and moment. This paper shows the proper approach to analyze the circular cross section cofferdam using 2D Finite Element Method (FEM) for the circular stiffener (ring beam) evaluation. Besides, the various shapes of cofferdam indluding circular cross section have modeled the 3D Finite Element Mothod (FEM). The circular cross section cofferdam shows the minimum reaction force compared with the other shapes of cofferdam.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.57-68
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• 1998

For free vibration of monosymmetric thin-walled circular arches including restrained warping effect, the elastic strain and kinetic energy is derived by introducing displacement fields of circular arches in which all displacement parameters are defined at the centroid axis. The cubic Hermitian polynomials are utilized as shape functions for development of the curved thin-walled beam element having eight degrees of freedom. Analytical solution for free vibration behaviors of simply supported thin-walled curved beam element is presented by evaluating elastic stiffness and mass matrices. In order to illustrate the accuracy and practical usefulness of this study, analytical and numerical solutions for free vibration of circular arches are presented and compared with solutions analyzed by the FEM using straight beam element.

• Computational Structural Engineering
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• v.9 no.3
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• pp.135-143
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• 1996

The differential equations governing both the free vibrations and buckling loads of tapered beam-columns of circular cross-section with constant volume are derived and solved numerically. The effects of axial load are included in the differential equations. The parabolic equation is chosen as the variable radius of circular cross-section for the tapered beam-column. In numerical examples, the clamped-clamped, clamped-hinged and hinged-hinged end constraints are considered. The variations of the frequency parameters and buckling load parameters with the non-dimensional system parameters are presented in figures and the configurations of strongest columns are obtained.

• Steel and Composite Structures
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• v.4 no.3
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• pp.169-188
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• 2004

A mechanics model is developed in this paper for concrete-filled steel CHS (circular hollow section) beam-columns. A unified theory is described where a confinement factor (${\xi}$) is introduced to describe the composite action between the steel tube and the filled concrete. The predicted load versus deformation relationship is in good agreement with test results. The theoretical model was used to investigate the influence of important parameters that determine the ultimate strength of concrete-filled steel CHS beam-columns. The parametric and experimental studies provide information for the development of formulas for the calculation of the ultimate strength of the composite beam-columns. Comparisons are made with predicted beam-columns strengths using the existing codes, such as LRFD-AISC-1999, AIJ-1997, BS5400-1979 and EC4-1994.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.465-472
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• 1998

In this study, analytic solution and finite element formulation for the free vibration analysis of thin-walled circular arch, based on linearized virtual work and Vlasov's assumption, including restrained warping effect and second order terms of finite semitangential rotations, is presented. The total potential energy is derived by applying the Hellinger-Reissner principle. In this formulation, all displacement parameters of deformation are defined at the centroid axis. For the finite element formulation, the two node cubic Hermitian polynomials are utilized as shape functions. In special case, potential energy functional of thin-walled curved beam with monosymmetric cross section is derived. From this methodology, analytic solution for the free vibration of monosymmetric circular arch with simply supported is derived. In order to illustrate the accuracy of this study, various parameter studies for free vibration of circular arches are presented and compared with numerical solution analyzed by the FEM using straight beam element.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.116-124
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• 2008

In order to evaluate the behavior patterns of the ring beam by excavation at the vertical wall with circular section, the measured field datum were analyzed and evaluated in this study. Additionally, stress patterns of the ring beam with the change of excavation depth were estimated by using FE analysis. As the results, it was shown that the tendency of the measured values for the behavior patterns of the ring beam is similar to the analyzed values in FE analysis. From the tendency, it was confirmed that the behaviors of the ring beam due to change of excavation depth can predict by FE analysis using the suggested method in this study.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.503-510
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• 2004

One of the methods improving the seismic behavior of a structure is the frame with reduced beam section (RBS) which cuts a segment of flanges of the beam near the beam-to-column connection so that the section with reduced flanges has smaller flexural strength than the beam end. It is difficult to analyze the RBS frame because RBS portion has circular-cut type flange. And inelastic response of the steel frame with the RBS is very sensitive to the RBS model. In this paper, the analytical models of RBS portion are investigated and the results of the inelastic analysis for RBS analytical models are compared and then the analytical model for RBS is determined based on the results of inelastic analysis. Inelastic behavior of the RBS frame and its dynamic characteristics are investigated for selected analytical model of RBS.

• Structural Engineering and Mechanics
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• v.85 no.4
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• pp.563-571
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• 2023

Girdling underpinning joints are key areas of concern for the pier-cutting bridge-lifting process. In this study, five specimens of an underpinning joint were prepared by varying the cross-sectional shape of the respective column, the process used to treat the beam-column interface (BCI), and the casting process. These specimens were subsequently analyzed through static failure tests. The BCI was found to be the weakest area of the joint, and the specimens containing a BCI underwent punching shear failure. The top of the girdling beam (GB) was subjected to a circumferential tensile force during slippage failure. Compared to the specimens with a smooth BCI, the specimens subjected to chiseling exhibited more pronounced circumferential compression at the BCI, which in turn considerably increased the shear capacity of the BCI and the ductility of the structure. The GB for the specimens containing a column with a circular cross-section exhibited better shear mechanical properties than the GB of other specimens. The BCI in specimens containing a column with a circular cross-section was more ductile during failure than that in specimens containing a column with a square cross-section.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.162-169
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• 1999

Intentionally weakened girders near the beam-to-colum connection lead ductile failures at the weakened points prior to potential brittle failure at the connection points subjected to strong earthquake. Recent research investigated cyclic behavior of composite beams with a rectangular web opening and find out ductile failure of such beams due to plastic hinge formation of T-section at the four corners of the rectangular opening. But eventual failures of T-sections are resulted from local buckling of T-section having a narrow stem and a narrow bound of plastic hinge formation. This continuing research proposes double-circular opening instead of rectangular one in ofter to improve energy dissipation capacity as well as composite beam strength, Experimental test of two specimens was carried out and its results are compared with those of nonlinear finite element analyses