• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.507-512
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• 2000

This paper presents a design procedure using the moment magnifier method that is applicable to RC flat plates subjected to combined axial compressive and uniform or non-uniform floor load. Based on the numerical results, the design values of the buckling coefficient and the effective flexural rigidity, that define the buckling force, have been proposed. Using these design values, this paper provides the design procedure for the moment magnifier method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.337-344
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• 2001

This paper is concerned with the change of joint rigidity in estimating the degree of semi-rigidity of connections and the buckling load in a single layer latticed dome. The estimations are based on information about the ratio for the rotational stiffness of the connection to the flexural stiffness of the member and the minimum eigenvalue of a structure for pinned, semi-rigid and completely rigid cases, respectively. Connection characteristics are reflected in the ratio control of joint rigidity for the DOFs to be related using the spring element by FEM.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.2
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• pp.94-104
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• 1999

Plate buckling is very important design criteria when the ship is composed of high tensile steel plates. In general, the plate element contributes to inplane stiffness against the action of inplane load. If the inplane stiffness of the plating decreases due to buckling including the secondary buckling, the flexural rigidity of the cross section of a ship's hull also decreases. In these cases, the precise estimation of plate's behaviour after buckling is necessary, and geometric nonlinear behaviour of isolated plates is required for structural system analysis. In this connection, the author investigated the geometric nonlinear behaviour of simply supported rectangular plates under uniaxial compression in the longitudinal direction in which the principle of minimum potential energy method is employed. Based on the energy method, elastic large deflection analysis of isolated palate is performed and simple expression are derived to discuss the bifurcation paint type buckling and limit point type buckling.

• Structural Engineering and Mechanics
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• v.90 no.5
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• pp.435-446
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• 2024

The use of cold-formed steel members is increasing day by day, especially in regions where earthquake effects are intensively experienced. Among cold-formed steel members (CFS), "channel" members are used more than other crosssectional members, especially in buildings or industrial structures. In recent years, several studies have been carried out on the axial load and flexural performance of these members under monotonic loading. In this study, CFS beam-column members were cyclically and monotonically loaded under combined axial load and biaxial bending moments, and their buckling behavior, load bearing capacity, stiffness, ductility, and energy absorption capacity were determined. For this purpose, monotonic and cyclic loading experiments were carried out on 30 CFS channel members at 15 different eccentricities. Then, material properties were determined by axial monotonic tensile and very low cycle fatigue tests for use in numerical studies. From the experimental results, the buckling modes, bearing capacities, ductility, stiffness, and energy absorption capacities of the members were obtained. The characteristics of the members were compared according to the stress state of the lips. According to the data obtained from the displacement transducer placed on the lips and on the back of the web, information about the buckling mode and curvature of the members was obtained. Finally, monotonic, and cyclic loading results were compared to determine the differences in the buckling behavior of the members.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.44-54
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• 2003

The experiments are performed to evaluate mechanical properties about foam and face materials of sandwich beams. These results are applied to the flexural wrinkling estimation of sandwich beam. The 3 point bending test shows that it is reasonable to include pre-buckling behavior in flexural wrinkling analysis, which is closer to experimental result. It is also conducted to survey the wrinkling behavior.

• Journal of Korean Society of Steel Construction
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• v.26 no.2
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• pp.91-103
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• 2014

High performance steel for bridges(HSB 800) with a minimum tensile stress of 800MPa was recently developed. However, the study for local buckling behavior of plate girders considering interactive effects of flanges and webs is still insufficient. In this study, the flange local buckling(FLB) strength of plate girders with HSB 800 was evaluated by nonlinear finite element analysis. The flanges and webs of plate girders having I-section were modeled as 3D shell elements in the nonlinear analysis. Initial imperfection and residual stress were imposed on the plate girder. The high performance steel was modeled as a multi-linear material. Thus, parametric study of compression flanges with a compact, noncompact and slender web was performed. The flange local buckling behavior of plate girders was analyzed, and the nonlinear analysis results were compared with the nominal flexural strength of both AASHTO LRFD(2012) and KHBDC LSD(2012) codes.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.747-754
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• 2002

Cold-formed steel truss system was reviewed in order to improve the various problems associated with the steel floor joist system, such as the structural deficiency caused by web punching and others. Two types of floor truss system using cold-formed steel were reviewed during this research project, including the square end type(SE type) and underslung type(EE type). The strctural behavior was analyzed using the AISI design criteria and various bending tests. Test results show that the SE type floor truss proved to be more efficient than the EE type when it is subjected to concentrated load, and that the unbraced length of the floor truss about the weak axis has much importance on the buckling strength of the floor truss. Test results indicate that their values surpass the calculated values predicated through the AISI design criteria.

• Steel and Composite Structures
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• v.45 no.6
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• pp.907-929
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• 2022

Compression experiments were conducted to investigate the compressive behavior of built-up open-section columns consisting of four cold-formed steel channels (BOCCFSs) of different lengths, thicknesses, and cross-section sizes (OB90 and OB140). The load-displacement curves, failure modes, and maximum compression strength values were analyzed in detail. The tests showed that the failure modes of the OB90 specimens transformed from a large deformation concentration induced by local buckling to flexural buckling with the increase in the slenderness ratio. The failure modes of all OB140 specimens were deformation concentration, except for one long specimen, whose failure mode was flexural buckling. When the slenderness ratios of the specimens were less than 55, the failure modes were controlled by local buckling. Finite element models were built using ABAQUS software and validated to further analyze the mechanical behavior of the BOCCFSs. A parametric study was conducted and used to explore a wide design space. The numerical analysis results showed that when the screw spacing was between 150 mm and 450 mm, the difference in the maximum compression strength values of the specimens was less than 4%. The applicability and effectiveness of the design methods in Chinese GB50018-2002 and AISI-S100-2016 for calculating the compression strength values of the BOCCFSs were evaluated. The prediction methods based on the assumptions produced predictions of the strength that were between 33% to 10% conservative as compared to the tests and the finite element analysis.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.679-690
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• 2011

Since the elastic buckling problem of the plate has been studied both experimentally and theoretically, the buckling loads with various boundary conditions and loads can be easily determined. Currently, flange and web design specifications are based on the buckling stress and the post-buckling strength and include a safety-factor. Therefore, this study extended suchresearch to the linear buckling theory with ideal conditions and to the ultimate state with post-buckling. The current specifications are based on elastic buckling stress; and therefore, further research on the ultimate behavior of the plate is required. The ultimate strength design concept, which allows finite deflection, is used in this studyto maximize the post-buckling strength in a steel box. An empirical equation, which provides the ultimate strength of the steel box due to the change in the slenderness and optimum rigidity, are suggested based on the experiment results. Moreover, the appropriateness of the current design specifications was analyzed and discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.481-492
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• 2018

The steel-plate concrete composite beam is composed of a steel plate, concrete and shear connector to combine two inhomogeneous materials. In general, the steel plate is assembled by welding an existing composite beam. In this study, the SPC beam was composed of folding steel plates and concrete, without a headed stud. The folding steel plate was assembled by a high strength bolt instead of welding. To improve the workability in a field construction, a hat-shaped cap was attached to the junction with a slab. Monotonic load testing under two points was conducted under displacement control mode to analyze the flexural strength of the SPC beam using a cap as the shear connector. Five specimens with shear connector types, protrusion length, and different thickness of steel plates were constructed and tested. The experimental results were analyzed through the relationship between the shear strength ratio and flexural strength in KBC 2009. The test results showed a shear strength ratio of more than 40 %. In the case of using a cap-like specimen as the shear connector, the flexural strength was 70% of the value calculated as a fully composite beam. In addition, the cap showed a smaller shear strength than the stud, but the cap served as a shear connection. When the thickness of the steel plate was taken as a variable, the steel plate exhibited a bending strength of approximately 70% compared to a fully formed steel plate, and exhibited similar deformation performance. Local buckling occurred due to incomplete composite behavior, but local buckling occurred at a 5% higher strength for a relatively thick steel plate. The buckling width also decreased by 15%.