• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3A
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• pp.149-160
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• 2012

Corrugated steel plates have several advantages such as high resistance for shear without stiffeners, minimization of welding process, and high fatigue resistance. To take advantage of these benefits, several researchers have attempted to use corrugated steel plate as a web of I-girders. The lateral-torsional buckling is the major design aspect of such I-girders. However, lateral-torsional buckling of the I-girder with corrugated steel webs still needs to be investigated especially for a real loading condition such as non-uniform bending. This paper investigated the lateral-torsional buckling strength of the I-girder with corrugated steel webs under linear moment gradient by using finite element analysis. From the results, it was found that the buckling behavior of the I-girder with corrugated steel webs differed depending on the number of periods of the corrugation. Also, a simple equation for the moment gradient correction factor of the I-girder with corrugated steel webs was suggested. The inelastic lateral-torsional buckling strength of the I-girder with corrugated steel webs was then discussed based on current design equations for ordinary I-girders and the results of finite element analysis.

• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.463-472
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• 2007

This paper presents theoretical and finite element analysis results for the lateral-torsional buckling of I-girders with corrugated web under uniform bending. Lateral-torsional buckling is a major design aspect for flexural members composed of thin-walled I-section. However, torsional rigidities such as the warping constants of the I-girders with corrugated web are not fully understood yet. In this paper, bending and pure torsional rigidities of I-girders with corrugated web are first described using the results of previous researchers. Then, the location of the shear center and the warping constants are derived. Using the derived section properties of I-girders with corrugated web, the lateral-torsional buckling strength is determined. Finite element analyses are conducted and the proposed lateral-torsional buckling strength of I-girders with corrugated web is successfully verified. Finally, the effects of corrugation profiles of the web on the lateral-torsional buckling load of I-girders with corrugated web are discussed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.4
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• pp.423-434
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• 2001

In this paper, a three-span continuous box girder is analysed by using elastic equation based on energy method, concerning the behaviour with the effects of bending and pure torsional moment. The statically indeterminate forces of a three-span continuous curved box girder are calculated by applying the principle of least work to this elastic equation. The influence line of shear force, bending moment, pure torsion, displacement and angle of rotation due to unit vortical load and unit torque for curved box girder are obtained. The internal forces of the curved box girder which the actual load is applied can be calculated using the influence line obtained from this study.

• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.281-290
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• 2003

A series of connection tests of portal frames which were composed of cold-formed steel studs and rafters was carried out to study the moment-rotation relation, the rotational rigidity, and the yield and the ultimate moment of the connections. The main factors of the tests were the thickness, the shape of the connecting members which were made of mild steel, and the torsional restraints of the test specimens. The test results were compared with those obtained through the non-linear analysis, for verification. The secant stiffness estimated from the experimental moment-rotation curve was proposed for the rotational rigidity of semi-rigid connections, and its validity was verified in the structural frame analysis.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.4
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• pp.45-52
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• 2004

Exact solution on the anti-symmetric response of ships having uniform sectional properties in waves is derived. Boundary value problem consisted of Timoshenko beam equation and free-free end condition is solved analytically. The responses are assumed as linear and wave loads are calculated by using strip method. Horizontal bending moment, shear force and torsional moment are calculated. The developed analysis model is used for the benchmark test of the numerical codes in this problem. Also the application on the preliminary design of barge-like ships and VLFS (Very Large Floating Structure) is expected

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.1
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• pp.35-44
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• 1990

Most of the medium-size ships are powered by large-bore, long-stroke, slow-speed and two-stroke diesel engines in order to improve the fuel efficiency. Such a propulsion plant develops low-frequency excitation forces/moments of significant magnitude. A RO/RO car/truck carrier is also one of the cases. In this paper, the rational methods for analysis of vertical and coupled horizontal-torsional vibrations are presented. Taking account of unusual characteristics of the hull form and structural systems, the emphasis is put on modelling methods based on beam analogy, calculation of system parameters such as added mass and its center, polar added-mass moment of inertia, shear coefficient of hull sections and coupling degree in antisymmetric modes, and modal analysis of forced vibrations.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.203-211
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• 2006

This paper presents a new, effective torsional constant for thin-waled open beams under concentrated and uniformly distributed torques. The proposed constant can be used directly, instead of the St. Venant torsional constant, for any generic comemrcial finite-element program, without modifying the algorithm. The derived torsional constant accounts for both the pure torsion and the warping torsion, and is equal to the St. Venant torsion constant times a correction factor. It is also shown, in the case of the St. Venant torsion, that the derived constant is identical to the torsional constant. The derived effective torsional constant is different from the one given by Elhelbawey et al. The pure torsional shear stress, the warping shear stress, and the warping normal stress were also determine d, using the maximum twisting angle. The accuracy of the proposed torsional constant was validated by comparing the numerical results with the closed-form solutions or other numerical results available in the literature.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.112-126
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• 1993

In this paper, unified requirements of IACS on longitudinal strength of ships are investigated using nonlinear wave loads analyses under short term irregular waves. Also, analyses on IACS wave data were carried out for the purpose of presenting the guideline for future use. While keeping theoretical consistensy, the rule requirements for horizontal shear force, bending moment and torsional moment are newly proposed for the ships of large deck openings bases on the calculation results for 17 sample ships. The requirements for side shell hydrodynamic pressure are also presented. All the calculated results are compared with other Societies and present KR rules. These formula will be checked when corresponding requirements of structural scantling are determined.

• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.299-311
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• 2003

This paper presents a finite element procedure to estimate the ultimate strength of space frames considering spread of plasticity. The improved displacement field is introduced based on the inclusion of second-order terms of finite rotations. All the non-linear terms due to bending moment, torsional moment, and axial force are precisely considered. The concept of plastic hinges is introduced and the incremental load/displacement method is applied for elasto-plastic analyses. The initial yield surface is defined based on the residual stress, and the full plastification surface is considered under the combined action of axial forces, bending and torsional moments. The elasto-plastic stiffness matrices are derived using the flow rule and the normality condition of the limit function. Finite element solutions for the ultimate strength of space frames are compared with available solutions and experimental results.