• Steel and Composite Structures
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• v.22 no.6
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• pp.1465-1486
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• 2016

Conventional plate I-girders are sensitive to local buckling of the web when they are subjected mainly to shear action because the slenderness of the web in out-of-plane direction is much bigger. The local buckling of the web can also cause the distorsion of the plate flange under compression as a thin-walled plate has very low torsional stiffness due to its open section. A new I-girder consisted of corrugated web, a concrete-filled rectangular tubular flange under compression and a plate flange under tension is presented to improve its resistance to local buckling of the web and distorsion of the flat plate flange under compression. Experimental tests on a conventional plate I-girder and a new presented I-girder are conducted to study the failure process and the failure mechanisms of the two specimens. Strain developments at some critical positions, load-lateral displacement curves, and load-deflection curves of the two specimens have all be measured and analyzed. Based on these results, the failure mechanisms of the two kinds of I-girders are discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.457-463
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• 2008

The longitudinal stiffener performs its role to increase the local buckling strength by making simple support upon compression flange. In the recent researches, it is investigated that compression flange with point supports on certain arrangement reveals the same strength with longitudinal stiffeners. From this results, it is predictable that shear stud could perform the role of longitudinal stiffener if shear stud embedded in concrete satisfies the requirement to point-support under yield stress of the compression flange. In this study, the researches were performed to investigate the optimally required arrangement space of longitudinal point-support for which the shear stud replacing the longitudinal stiffeners and simultaneously determine the required numbers and space of shear stud for completely composite behavior between compression bottom flange and bottom concrete on the double composite girder system.

• Steel and Composite Structures
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• v.23 no.3
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• pp.331-338
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• 2017

Cold-formed lipped channel columns (CFLCCs) have been widely used in light gauge steel constructions. The distortional buckling is one of the important buckling modes for CFLCCs and the distortional buckling critical load depends significantly on the rotational restrain stiffness generated by the web to the lipped flange. First, a simplified explicit expression for the rotational restraint stiffness of the lipped flange has been derived. Using the expression, the characteristics of the rotational restraint stiffness of the lipped flange have been investigated. The results show that there is a linear coupling relationship between the applied forces and the rotational restraint stiffness of the lipped flange. Based on the explicit expression of the rotational restraint stiffness of the lipped flange, a simplified analytical formula has been derived which can determine the elastic distortional buckling critical stress of the CFLCCs subjected to axial compression. The simplified analytical formula developed in this study has been shown to be accurate through the comparisons with results from the distortional buckling analyses using the ANSYS finite element software. The developed analytical formula is easy to apply, and can be used directly in practical design and incorporated into future design codes and guidelines.

• Journal of Korean Society of Steel Construction
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• v.29 no.4
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• pp.281-289
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• 2017

The current AASHTO LRFD and Eurocode 3 specifications have been found to underestimate the flexural strength of longitudinally reinforced plate girders. This is because the web-flange interaction is not considered appropriately when a web is reinforced. The buckling strength of compression flange increases due to the improved rotational restraint to the compression flange. Also, the compression flange and the longitudinal stiffener could constrain the web rotation, so that a certain area of the web reaches yield strength. In this study, a model for evaluating the flexural strength is proposed for plate girders reinforced with one line of longitudinal stiffeners, considering the increase of the buckling strength of the compression flange and the actual stress distribution of the web. The flexural strengths of the conventional steel(SM490) and the high-strength steel(HSB800) plate girders were evaluated from the nonlinear analysis and the applicability of the proposed model was analyzed.

• Steel and Composite Structures
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• v.44 no.6
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• pp.883-898
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• 2022

A hollow-core partially-encased composite beam, named HPEC beam, is investigated in this paper. HPEC beam comprises I-beam, longitudinal reinforcement, stirrup, foam formwork, and cementitious grout. The foam formwork is located on both sides of the web, and cementitious grout is cast within the steel flange. To investigate the shear performance of HPEC beams, static loading tests of six HPEC beams and three control beams were conducted. The shear span ratio and the number of studs on the shear behavior of the HPECspecimens were studied. The failure mechanism was studied by analyzing the curves of shear force versus both deflection and strain. Based on the shear span ratio (𝜆), two typical shear failure modes were observed: shear compression failure when 1.6 ≤ 𝜆 ≤ 2; and diagonal compression failure when 𝜆 ≤ 1.15. Shear studs welded on the flange can significantly increase the shear capacity and integrity of HPEC beams. Flange welded shear studs are suggested. Based on the deformation coordination theory and superposition method, combined with the simplified modified compression field model and the Truss-arch model, Modified Deformation Coordination Truss-arch (M.D.C.T.) model was proposed. Compared with the shear capacity from YB9038-2006 and JGJ138-2016, the calculation results from M.D.C.T. model could provide reasonable predictions.

• Journal of Power System Engineering
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• v.21 no.1
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• pp.57-62
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• 2017

The flexible joint with bellows and flange is made by welding bellows and flange in general. The welded parts cause a crack or demage in the flexible joint due to continuous vibration and fatigue limit. This paper is concerned with development of flexible joint with non-welded, free rotation of flange and non-packing to improve fatigue failure condition between bellows and flange. The support box and support plate that are components of press part are designed to compress fore-end of bellows only without demage of bellows. The production system of flexible joint is designed with piston attached on the compression side. The simulation is performed using Deform 3D software. As the result of simulation, the shape of compressed bellows was most proper in the compression power of $157kg{\cdot}f$ and any deformation has not occurred at a part besides fore-end. The result show that the production possibility of the designed flexible joint.

• Steel and Composite Structures
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• v.45 no.1
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• pp.51-66
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• 2022

This paper presents the axial compression behavior of partially encased composite (PEC) columns using H-shaped structural steel. In the experimental program, a total of eight PEC columns with H-shaped steel sections of different flange and web slenderness ratios were tested to investigate the interactive mechanism between steel and concrete. The test results showed that the PEC columns could sustain the load well beyond the peak load provided that the flange slenderness ratio was not greater than five. In addition, the previous analytical model was extended to predict the axial load-strain relationships of the PEC columns with H-shaped steel sections. A good agreement between the predicted load-strain relationships and test data was observed. Using the analytical model, the effects of compressive strength of concrete (21 to 69 MPa), yield strength of steel (245 to 525 MPa), slenderness ratio of flange (4 to 10), and slenderness ratio of web (10 to 25) on the interactive mechanism (K_h = confinement factor for highly confined concrete and K_w = reduction factor for steel web) and ductility index (DI = ratio between strain at peak load and strain at proportional load) were assessed. The numerical results showed that the slenderness of steel flange and yield strength of steel significantly influenced the compression behavior of the PEC columns.

• Structural Engineering and Mechanics
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• v.29 no.6
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• pp.623-642
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• 2008

While spatial plastic mechanism analysis has been widely and successfully applied to thinwalled steel structures to analyse the post-failure behaviour of sections and connections, there remains some contention in the literature as to the basic capacity of an inclined yield line. The simple inclined hinge commonly forms as part of the more complex spatial mechanism, which may involve a number of hinges perpendicular or inclined to the direction of thrust. In this paper some of the existing theories are compared with single inclined yield lines that form in flange outstands, by comparing the theories with plate tests of plates simply supported on three sides with the remaining (longitudinal) edge free. The existing mechanism theories do not account for different in-plane displacement gradients of the loaded edge, nor the slenderness of the plates, and produce conservative results. A modified theory is presented whereby uniform and non-uniform in-plane displacements of the loaded edge of the flange, and the slenderness of the flange, are accounted for. The modified theory is shown to compare well with the plate test data, and its application to flanges that are components of sections in compression and/or bending is presented.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.737-749
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• 2007

Flexural design of double composite box girder over the interior pier for three-span continuous bridge was performed by the LRFD method. The maximum span length of the continuous bridge ranged from 80m to 120m and the relative ratio of the span length was assumed to be 1:1.25:1. The girder section was designed for the strength limit state and service limit state with additional design check for constructibility. Before the bottom concrete and compression flange showed a complete composite action, the buckling of lower compression flange was checked. The flexural stiffness and flexural resistance characteristics for the section and for the constituent members such as tension flange, compression flange, and web were analyzed for different thicknesses of the bottom concrete on top of the compression flange. The effect of the distribution ratio of steel between the top and bottom flanges was investigated by analyzing ductility behavior and stress distribution through the girder's depth for several different relative area ratios of steel between the top and bottom flanges. It was found that a total amount of 15% of steel can be saved by applying the double composite system compared with that of the conventional composite system.

• Transactions of Materials Processing
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• v.12 no.2
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• pp.110-115
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• 2003

This paper is concerned with the compression test and forming process of flange by using virtual reality and analysis(simulation) program. This virtual manufacturing can be carried out one personal computer without any expensive devices for experiment. The virtual manufacturing composed of three modules such as the imput, calculation and the output modules on internet. Internet user can give the material's property and process parameters to the sever computer at the input module. On the calculation module, a simulator computes the virtual manufacturing process by analysis program and stores the data as a file. The output module is the program in which internet user can confirm virtual manufacturing results by showing tables, graphs, and 3D animation. This programs is designed by an internet language such as HTML, CGI, VRML and JAVA ,while analysis programs use the finite increasing, the virtual manufacturing technique will substitute many real experiments in the future.