• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3C
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• pp.91-96
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• 2009

The purpose of this study was to investigate a method for the strength enhancement of wale in temporary retaining structures. Tests on the wale structures strengthened with carbon fibre reinforced plastic (CFRP) strips and prestressed with seven wire strands were conducted. From this test, it is found that the flexural stiffness and strength of the wales strengthened with CFRP strips and seven wire strands were significantly improved compared to the unstrengthened one. The ultimate tensile strains of attached CFRP strips on the steel beam were in the range of 8,000 and $11,000{\mu}{\epsilon}$, and it is noticed that the bonding ability with steel and CFRP strips is good. In this paper, a new method for enhancing the strength of wale in retaining structures is suggested.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.605-615
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• 2014

The purpose of this study is to propose an economic new type rib by applying plate stiffening methods of the corrugated plate and the honey-comb sandwich panel to the steel deck plate and comparing the new type rib with existing open and closed ribs. The trapezoidal corrugated type, ㄹ type, honey-comb type and ㅁ type ribs are considered as new type ribs and the moment and the steel volume are compared with that of open ribs and closed ribs. The results shows that the honey-comb type and ㅁ type ribs are good in aspects of economic feasibility and the ㅁ type is better than the honey-comb type. To make the ㅁ type rib applicable to the steel deck plate, the sensitivity analysis and parametric study are performed and the system to select the proper section under the particular stress condition is established. The closed rib of real bridges is compared with the ㅁ type rib of the proposed system and it is known that the new type rib is more economic. Therefore, more economic steel deck plates can be achieved by using the system proposed in this study for the plate stiffened with the new ㅁ type rib.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.73-81
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• 2004

In this study, experimental research was carried out to improve earthquake-resistant performance for the retrofitting of reinforced concrete beam-column joints using carbon fiber materials in existing reinforced concrete building. Six reinforced concrete beam-column joints were constructed and tested to evaluate the retrofitting effect of test variables, such as the retrofitting materials and retrofitting region(plastic hinge, beam-column joint) under load reversals. Test results show that retrofitting specimen(RPC-CP2, RPC-CR, RJC-CP, RJC-CR), using new materials(carbon fiber plate, carbon fiber rod and carbon fiber sheet), designed by the improvement of earthquake-resistant performance and ductility, attained more load-carrying capacity and stable hysteretic behavior.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.1-7
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• 2008

When historical or cultural buildings need to be repaired or reinforced, the changes of original features should be minimized, and the strengths of structures should be improved. Among the existing methods to reinforce historical wood structures, the carbon fiber reinforcement polymer (CFRP) installation method is one of the best ones to achieve the afore-mentioned requirements. Therefore, this study aims at investigating the reinforcing effects and failure modes of timber beams reinforced with the inserted CFRP, a part of roof trusses in modern wood structures, and at providing the fundamental test data to estimate the CFRP rein-forced timber beam in the application of this reinforcing method. The primary parameters in this study were the layout and amount of CFRP. It was observed that, when $0.3{\sim}0.7%$ of CFRP were installed, the strengths of reinforced timber beams increased up to 173% compared to its original strength, but their strengthening effects were heavily influenced by the characteristics of timber such as burls. In order to improve the applicability of this strengthening method, fundamental understandings on the characteristics of wood would be necessary, and there would be in need of researches on the non-destructive test for wood structures as well.

• Journal of Korean Association for Spatial Structures
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• v.5 no.4 s.18
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• pp.71-77
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• 2005

Bonded CFRP Plate method used murk in reinforcement method is very efficient for stress increment of reinforced members. But CFRP plate dosen't display enough its capacity and have the destruction characteristic of premature failure that reach failure by debond plate, because near-surface-bond using epoxy. Such destruction character of reinforced specimens take the influence at variables as steel reinforcement ratio, concrete strength, kind of reinforcement materials, reinforced length, property of epoxy used in binder and so on. In this study, performed experiment results are compared and considered on flexural performance of Near Surface Mounted Reinforcement used CFRP-Rod, as complement about structural behavior of RC beam reinforced flexural capacity in CFRP plate and premature failure of reinforcement material. Main variables of RC beam applied CFRP Plate external bond method are experimental variables as reinforcement length, reinforcement position (tension face and side face of beam) and existence of ironware in end parts. In case of CFRP-Rod, variable is reinforcement length.

• Composites Research
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• v.14 no.4
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• pp.1-7
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• 2001

This paper presents the results of an analytical investigation pertaining to the elastic local buckling behavior of asymmetric edge stiffened orthotropic open section structural member under uniform compression. The asymmetric edge stiffener is considered as a beam element neglecting its torsional rigidity. We suggested the analytical model of asymmetric edge stiffeners which is composed of a strip of flange plate, equal width of edge stiffener, and a plate attached at the flange end, and computed the moment of inertia of the stiffener about an axis through the centroid of the ensuing cross-section. Using the derived equation, the local buckling coefficients of asymmetrically edge stiffened orhtotropic I-section columns are predicted and the results are presented in a graphical form.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.48-58
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• 2002

There is a purpose of this study for the proposal of the optimum technique utilized for the vibration design initial step. The stiffened plate structure for the ship hull is made for analysis model. To begin with, dynamic characteristics of stiffened plate structure is analysed using FEM. Main vibrational mode of the structure is decided in the analytical result of FEM. The simplified equation on the natural frequency of the main vibrational mode is induced. Next, sensitivity analysis is carried out using the simplified equation, and rate of change of dynamic characteristics is calculated. Then, amount of design variable is calculated using this sensitivity value and optimum structural modification method. The change of natural frequency is made to be an objective function. Thickness of panel, cross section moment of stiffener and girder become a design variable. The validity of the optimization method using simplified equation is examined. It is shown that the result effective in the optimum modification for natural frequency of the stiffened plate structure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.5
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• pp.414-420
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• 2014

In this paper, the vibration characteristics of the trapezoidal corrugated plate with axial stiffeners and lumped masses are investigated by the analytical method. The corrugated plate can be treated as an equivalent orthotropic plate as this plate has different flexure properties in two perpendicular directions; flexible in the corrugation direction and stiff in the transverse direction. The effective extensional and flexural stiffness of the equivalent plate are considered to obtain the precise solution in the analysis. The plate is stiffened by concentric stiffeners horizontally to the corrugation direction. The discrete stiffener theory is adopted to consider the position of stiffener. To demonstrate the validity of the proposed approach, the comparison is made with the results of 3D ANSYS finite element solutions. Some numerical results are presented to check the effect of the geometric properties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.816-819
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• 1997

The operation of femoral non-union after IM(Intramedullary) nailing in distally femoral fractures is considered. Augmentive plate fixation is the management of femoral non-union after IM nailing. The purpose of this study is to compare the bending, torsional stiffness and stress distribution of the two operations by the FEM(Finite Element Method). Augmentive plate fixation is better than IM nail fixation. These results conclude that plate augmentation is a useful method for the unstable femoral non-union after interlocking IM nailing.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.788-794
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• 2014

In this paper, the transient response analysis of the trapezoidal corrugated plate subjected to the pulse load is investigated by the theoretical method. Three types of pulse loads are considered: stepped, isosceles triangular and right triangular pulse loads. The corrugated plates can be represented as an orthotropic plate. Both the effective extensional and flexural stiffness of this equivalent orthotropic plate are considered in the analysis. The plate is stiffened by concentric stiffeners perpendicular to the corrugation direction. The stiffening effect is represented by the discrete stiffener theory. This theoretical results are validated by those obtained from 3D finite element analysis based on shell elements. Some numerical results are presented to check the effect of the geometric properties.