Skip to main content
Article thumbnail
Location of Repository

Lateral buckling of steel I-section bridge girders braced by U-frames

By Rose Mui Yuen

Abstract

Tbe study consists of an experimental and analytical investigation into the lateral buckling behaviour of steel I-section girders braced by continuous or discrete\ud U-frames. Scaled down laboratory tests on twin I-section girders have been carried out under full instrumentation and are reported. Lateral deflection of the compression\ud flanges and final buckling modes were recorded and the coupling effect of U-frame action is clearly demonstrated. The failure loads obtained were generally higher than\ud the corresponding design values according to BS5400.\ud \ud Using a large displacement elasto-plastic finite element package, ABAQUS, finite element idealisations of the tests were established and analysed. Good correlation between the experiments and the numerical analyses was reached. Validity\ud of the ABAQUS package was confirmed and first order elements were sufficiently effective for the analysis.\ud \ud This was followed by further investigation of a wider range of I-section girders using ABAQUS. The ultimate bending resistance of the girders obtained from finite element analysis was in general greater than the corresponding design values to BS5400, particularly so with girders of high slendemess. Thus the present design method is considered to be unduly conservative.\ud \ud The cause of this conservatism in BS5400 is discussed. The expression for the calculation of effective length of U-frame braced girders was found to be reasonable. Based on the results from ABAQUS and reviews of the limited research directly related to this study, two main parameters in the BS5400 expression for beam slenderness seem inappropriate for lateral buckling of an I-section girder under U-frame restraint. These are the radius of gyration of the whole girder section and the ratio of overall depth of a girder to mean flange thickness. Instead, radius of gyration\ud of the compression flange together with a contribution from the adjoining web section was found to be more appropriate as also was the web slenderness. In addition, a modification is proposed to the present limiting stress curve for lateral buckling of bare steel I-section girders. Empirically derived factors have been introduced. The\ud general procedures in the existing design method to BS5400 remain similar, however.\u

Publisher: School of Civil Engineering (Leeds)
Year: 1992
OAI identifier: oai:etheses.whiterose.ac.uk:437

Suggested articles

Citations

  1. (1989). An Investigation into Bracing System and the Use of U-Frames - Laboratory Test Model',
  2. (1990). An Investigation Into Bracing Systems And Use of U-frame on Steel Bridges',
  3. (1983). Beams and Beam Columns: Stability and Strength, doi
  4. (1982). Bracing Requirements
  5. (1982). BS5400: Part 3, Code of Practicefor The Design of Steel Bridges, British Standard Institution,
  6. (1974). Buckling of Composite Beams in Negative Bending',
  7. (1983). Buckling of Lateral Braced Beams', doi
  8. (1952). Buckling Strength of Metal Structures, Engineering Societies Monographs,
  9. (1989). Buckling Strength of Partially Restrained I-Beams', doi
  10. (1987). Building Curves for Elastically Supported Columns with Varying Axial Force to Predict Lateral Buckling of Bearns', doi
  11. (1989). Computing Centre, ABAQUS Finite Element System,
  12. (1987). Continuous Composite Bridge Beams - Stability of the Steel Compression Flange in Hogging Bending',
  13. (1979). Design for Structural Stability, Constrado Monographs, Coffins,
  14. (1981). Design of Beams and Plate Girders - Treatment of Overall and Local Flange Buckling,
  15. (1975). Design of Diaphragm Braced I-Beams',
  16. Design: Bracings',
  17. (1978). Distortional and Lateral Buckling of I-Beams', doi
  18. (1990). Distortional Buckling Strength of Elastically Restrained Monosymmetrical I-Beams', Thin-Walled Structures, doi
  19. (1991). Distortional Lateral Buckling of Continuous Composite Beams', doi
  20. (1982). Distortional Lateral Buckling of Unstiffened Composite Bridge Girders', doi
  21. (1989). Eastic Buckling of inter-braced Girders',
  22. (1979). Elastic Lateral Buckling of Continuously Restrained Beam-Columns', The Profession of a Civil Engineer.,
  23. (1986). Elastic Torsional Buckling of Through Plate Girder Rail Bridges',
  24. Experimental Verification of the Strengths of Plate Girders Designed in accordance with the Revised British Standard 153: Test on Full-Size and on Model Plate Girders', Structural and Building Engineering Division, doi
  25. Experiments on Continuous Composite Beams', doi
  26. (1985). Ile Analysis of Non-Linear and Ultimate Load Behaviour of Plate Structure by Finite Element Method', doi
  27. (1951). Ile Influence of Resu-aints on the Stability of Beams,
  28. (1988). Inter-Braced Column-Beams Steel Framed Structures', Steel-concrete composite structures - Stability
  29. (1977). International Colloquiurn on Stability, Introductory Report,
  30. Ivanov's Yield Criterion for Ibin-Plates and Shell Using Finite Elements',
  31. Large-deflection Elasto-plastic Buckling Analysis of Plates Using Finite Element',
  32. Large-Deflection Elasto-Plastic: Buckling Analysis of Eccentrically Stiffened Plates Using Finite Element',
  33. (1960). Lateral Bracing of Columns and Beams', doi
  34. Lateral Buckling in Continuous Composite Bridge Girders'.
  35. (1987). Lateral Buckling in Diaphragmed-braced Beams and Continuous Composite Bridge Girders,
  36. (1990). Lateral Buckling of Beams Analysed As Elastically Supported Column Subject to a Varying Axial Force'. doi
  37. Lateral Buckling of Beams Braced by Purlins', doi
  38. (1986). Lateral Buckling of Steel Beams with Reinforced Concrete Slab'.
  39. (1988). Lateral Distortional Buckling: Predicting Elastic Critical Stress', doi
  40. (1985). Lateral Stability of I-Beams Restrained by Profiled Sheetings',
  41. (1972). Local Buckling in Continuous Composite Beams',
  42. (1988). Notes and Sketches of Steel Bridge Arrangements,
  43. (1974). Some approximations in the non-linear analysis of rectangular plates using finite elements', doi
  44. Strength and Deformability of H-Shaped Steel Beams and Lateral Bracing Requirements', doi
  45. Tests on Three-span Continuous Composite Beams', doi
  46. The Basis for doi
  47. (1989). The Welding Institute, 'Ultirnate Load Test on To Scale Model of a Steel Plate Girder Bridge Braced with U-Framel,
  48. (1980). Web Distortion and Flexural-Torsional Buckling', doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.