• Steel and Composite Structures
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• v.44 no.3
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• pp.437-450
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• 2022

When the vertical load-bearing members in high-rise structures fail locally, the beam-column joints play an important role in the redistribution of the internal forces. In this paper, a static laboratory test of three full-scale flush flange beam-reinforced connections with side and cover plates (CP-FBSP connection) with double half-span steel beams and single L-shaped columns composed of concrete-filled steel tubes (L-CFST columns) was conducted. The influence of the side plate width and cover plate thickness on the progressive collapse resistance of the substructure was thoroughly analyzed. The failure mode, vertical force-displacement curves, strain variation, reaction force of the pin support and development of internal force in the section with the assumed plastic hinge were discussed. Then, through the verified finite element model, the corresponding analyses of the thickness and length of the side plates, the connecting length between the steel beam flange and cover plate, and the vertical-force eccentricity were carried out. The results show that the failure of all the specimens occurred through the cracking of the beam flange or the cover plate, and the beam chord rotations measured by the test were all greater than 0.085 rad. Increasing the length, thickness and width of the side plates slightly reduced the progressive collapse resistance of the substructures. The vertical-force eccentricity along the beam length reduced the progressive collapse resistance of the substructure. An increase in the connecting length between the beam flange and cover plate can significantly improve the progressive collapse resistance of substructures.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.342-347
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• 2006

In this paper, we have designed 800[MHz] broad band antenna that is improves a narrow bandwidth problem of microstrip antenna and it will be able to integrate GSM, TRS band including the CDMA band. It had L-shaped feeding structure and added the U-slot it used a duplex resonance effect. Also for the improvement of profit the stack it did with the perpendicular. It seems to be good quality that design and manufactured antenna frequency bandwidth(VSWR 2:1) is 789~1086[MHz] with 297[MHz](33%). Also the E-plan and H-plan all profit 9.4[dBi] above, 3[dB] beam width was visible the quality which above $61^{\circ}$ is improved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.219-222
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• 2006

In this paper, we have designed 800MHz band broadband antenna which is improves of microstrip antenna narrow bandwidth problem including the CDMA band and be able to integrated the GSM and TRS band will design. It used the duplex resonance effect it had the L-Shaped feeding structure which adds the u-slot. It was measured that the frequency bandwidth of the designed antenna which is planed $897MHz\sim1013MHz$ with 215MHz(23.8%). And the antenna gain is 9.3dBi, 3dB beam width $60^{\circ}$ in both the E-plane and H-plane.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.998-1002
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• 2006

In this paper, we have designed 800MHz band broadband antenna which is improves of microstrip antenna narrow bandwidth problem including the CDMA band and be able to integrated the GSM and TRS band will design. It used the duplex resonance effect it had the L-Shaped feeding structure which adds the u-slot. It was measured that the frequency bandwidth of the designed antenna which is planed $897MHz\sim1013MHz$ with 215MHz(23.8%). And the antenna gain is 9.3dBi, 3dB beam width $60^{\circ}$ in both the E-plane and H-plane.

• Structural Engineering and Mechanics
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• v.21 no.1
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• pp.19-33
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• 2005

An improved shear deformable thin-walled curved beam theory to overcome the drawback of currently available beam theories is newly proposed for the spatially coupled free vibration and elastic analysis. For this, the displacement field considering the shear deformation effects is presented by introducing displacement parameters defined at the centroid and shear center axes. Next the elastic strain and kinetic energies considering the shear effects due to the shear forces and the restrained warping torsion are rigorously derived. Then the equilibrium equations are consistently derived for curved beams with non-symmetric thin-walled sections. It should be noticed that this formulation can be easily reduced to the warping-free beam theory by simply putting the sectional properties associated with warping to zero for curved beams with L- or T-shaped sections. Finally in order to illustrate the validity and the accuracy of this study, finite element solutions using the isoparametric curved beam elements are presented and compared with those in available references and ABAQUS's shell elements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.343-355
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• 2017

In this study, an Assembled Earth Retaining Wall (AER wall) is newly proposed. The AER wall combined stabilizing piles names as Back Supporting Beam is developed to improve stability and economics of existing retaining walls. For the verification of the AER wall, the field model tests and 3D numerical analyses were performed. As a result of the field tests, it can be confirmed that the earth pressure is considerably reduced compared with the L-shaped retaining wall. Also, the 3D numerical analyses show that AER wall is at least 29.85% more effective at lateral displacement than general L-shaped retaining wall. In other words, AER wall is expected to raise economical efficiency because of excellent mechanical stability of Back Supporting Beam.

• Structural Engineering and Mechanics
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• v.54 no.1
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• pp.1-17
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• 2015

An experimental investigation is conducted to examine the behavior and cracking of steel fiberre-inforced concrete spandrel L-shaped beams subjected to combined torsion, bending, and shear. The experimental program includes 12 medium-sized L-shaped spandrel beams organized into two groups, namely, specimens with longitudinal reinforcing bars, and specimens with bars and stirrups. All cases are examined with 0%, 1%, and 1.5% steel fiber volume fractions and tested under two different loading eccentricities. Test results indicate that the torque to shear ratio has a significant effect on the crack pattern developed in the beams. The strain on concrete surface follows the crack width value, and the addition of steel fibers reduces the strain. Fibrous concrete beams exhibited improved overall torsional performance compared with the corresponding non-fibrous control beams, particularly the beams tested under high eccentricity.

• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.589-604
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• 2005

To overcome the drawback of currently available curved beam theories having non-symmetric thin-walled cross sections, a curved beam theory based on centroid-shear center formulation is presented for the spatially coupled free vibration and elastic analysis. For this, the displacement field is expressed by introducing displacement parameters defined at the centroid and shear center axes, respectively. Next the elastic strain and kinetic energies considering the thickness-curvature effect and the rotary inertia of curved beam are rigorously derived by degenerating the energies of the elastic continuum to those of curved beam. And then the equilibrium equations and the boundary conditions are consistently derived for curved beams having non-symmetric thin-walled cross section. It is emphasized that for curved beams with L- or T-shaped sections, this thin-walled curved beam theory can be easily reduced to the solid beam theory by simply putting the sectional properties associated with warping to zero. In order to illustrate the validity and the accuracy of this study, FE solutions using the Hermitian curved beam elements are presented and compared with the results by previous research and ABAQUS's shell elements.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.1033-1039
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• 2006

To overcome the drawback of currently available curved beam theories having non-symmetric thin-walled cross sections, a curved beam theory based on centroid-shear center formulation is presented for the spatially coupled free vibration and elastic analyses. For this, the elastic strain and kinetic energies considering the thickness-curvature effect and the rotary inertia of curved beam are derived by degenerating the energies of the elastic continuum to those of curved beam. And then the equilibrium equations and the boundary conditions are consistently derived for curved beams having non-symmetric thin-walled cross section. It is emphasized that for curved beams with L- or T-shaped sections, this thin-walled curved beam theory can be easily reduced to tl1e solid beam theory by simply putting the sectional properties associated with warping to zero. In order to illustrate the validity and the accuracy of this study, FE solutions using the Hermitian curved beam elements are presented and compared with the results by previous research and ABAQUS's shell elements.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.295-300
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• 2002

The construction of the T-shaped post-column flow cell has been changed to enhance the practicability as a UV-visible absorbance detector for capillary electrophoresis. In this new design, a rectangular cube-shaped inner structure is employed, which completely fits the outer rectangular tubing. This arrangement has greatly facilitated the fabrication of the T-cells. In addition, the volume for the auxiliary flow has been dramatically reduced down to 300 ${\mu}L$, and its volume flow rate is optimized at 4.2 ${\mu}L$/min. The short optical path length in the sheath flows (500 ${\mu}m$ on each side) minimizes background absorption, and thus enhances its performance in low-UV wavelengths. We have optimized the auxiliary flow rate at 50 ${\mu}m$/s, so that migration times are insensitive to the flow rate. This optimization has improved repeatabilities in migration times and peak heights. A double-beam detection scheme using a pair of photodiodes is employed to increase the signal-to-noise ratio.