Location of Repository

Instability of composite beams in hogging bending

By Shiming Chen

Abstract

This work is concerned with local buckling and lateral distortional buckling, two\ud aspects of instability that govern the design of composite beams in hogging regions.\ud Local buckling in hogging regions of a continuous composite beam was modelled\ud by moment curvature characteristics of a cantilever, modified by two curvature\ud ratios, K1 and K2. Test based expressions for K1 and K2,\ud in terms of a combined\ud slenderness λc, were developed, and subsequently used in numerical analyses\ud of 50 two-span composite beams to assess moment redistribution allowed for Class\ud 2 beams by draft Eurocode 4. The analyses include effects of non-linear material\ud properties, residual stresses and local buckling. The parametrical studies include\ud adverse values, in relation to practice, of relative length of adjacent spans, span-to-depth\ud ratio, and ratio of hogging to sagging moment of resistances. It is concluded\ud that the redistribution of elastic bending moments allowed by the draft Eurocode 4\ud is safe and economical.\ud Distortional lateral buckling of composite beams with both continuous and discrete\ud U-frame actions was studied experimentally. Distortional lateral buckling was\ud found in the tests of two composite beams with inverted U-frame actions. Web\ud distortion was effectively reduced by vertical web stiffeners, which form a part of\ud discrete U-frames together with the slab and the connection of U-frame. The work\ud provides background to assess lateral buckling strength for composite beams with\ud both continuous and discrete U-frame actions. A further theoretical approach on\ud the topic of discrete inverted U-frame action was presented.\ud Strength and stiffness of discrete U-frame connections were also studied. The\ud strength of a discrete U-frame connection was found to be influenced by both the\ud shear failure of concrete, and the yielding of steel top flange in the connection. A\ud simple rule to assure strength of U-frame connections is proposed by checking these\ud two failures separately. The prediction of shear failure of a U-frame connection is\ud based on a truss model, and the prediction of failure in the steel top flange is based\ud on a rigid plastic mechanism. A semi-empirical formula for flexibility of a U-frame\ud connection was derived. They were all checked against test results. Interactive U-frame\ud force and U-frame stiffness were also studied. A tentative design method for\ud discrete U-frame composite beams was proposed

Topics: TA
OAI identifier: oai:wrap.warwick.ac.uk:4009

Suggested articles

Preview

Citations

  1. (1977). A basis for the design of column bracing.
  2. (1992). A simply supported imperfect column with a transverse elastic restraint at any position. Part 2: behaviour. doi
  3. (1992). A simply supported imperfect column with a transverse elastic restraint at any position. Part 2: design models. doi
  4. (1991). An investigation into bracing systems and the use of the Uframes on steel bridges. Contract Report,
  5. (1980). Background to buckling.
  6. (1984). Bracing requirement in thin-walled structures. Developments in thin-walled structures-2, doi
  7. Buckling curves for elastically supported columns with varying axial force to predict lateral buckling of beams. doi
  8. (1989). Buckling in continuous composite beams. University of Warwick, 19907 PhD thesis. [161 Kato B. Rotation capacity of H-section members as determined by local buckling.
  9. (1974). Buckling of composite beams in negative bending.
  10. Buckling of continuous steel girders with flange restraint. doi
  11. Buckling of laterally braced beams. doi
  12. Buckling of laterally or torsionally restrained beams.
  13. (1970). Composite action at the supports of continuous beams.
  14. (1986). Composite structures of steel and concrete. doi
  15. (1982). concrete and composite briges. Code of practice for design of steel bridges. doi
  16. Continuous construction in steel for roofs and composite floors.
  17. (1985). Definition of flange slenderness limits on the basis of rotation capacity values. doi
  18. (1988). Design of steel structures. doi
  19. (1982). Distortional buckling of thin-web beamcolumns. Engrg Structs,
  20. Distortional lateral buckling of continuous composite beams. doi
  21. (1983). Distortional lateral buckling of unstiffened composite bridge girders. doi
  22. Editorial Panel For Eurocode 4. Design of composite steel and concrete structures: general rules and rules for buildings. Eurocode 4: Part 1, revised draft, doi
  23. Effects of web deformation on the torsion of I-beams.
  24. (1990). et a]. Nachweisgegen Biegedrillknicken bei Verbundtragern. Der Sta.
  25. (1959). Hilstafeln zur Berechnung von Spannungsproblemen der Theorie zweiter Ordnung und von Knickproblemen. Stahlbau-Verlag, Koln,
  26. (1965). Inelastic beams under uniform
  27. Inelastic buckling of composite bridge girders near internal supports. doi
  28. Inelastic distortional buckling of I-beams. doi
  29. (1979). Institution. Design of composite bridges.
  30. (1983). Institution. Method for determination of compressive strength of concrete cubes. doi
  31. (1958). Institution. Specification for steel girder bridges. doi
  32. (1983). Institution. Tensile testing of metals.
  33. (1973). Large deflection elastoplastic buckling analysis of plates using . finite elements,
  34. Lateral bracing of columns and beams. doi
  35. (1991). Lateral buckling in continuous composite bridge.
  36. Lateral buckling of beams analysed as elastically supported columns subject to a varying axial force. doi
  37. Local buckling analysis of composite beams. doi
  38. (1991). Local buckling and moment redistribution doi
  39. (1970). Local buckling in composite beams.
  40. Local distortional and lateral buckling of I-beams. doi
  41. (1967). Local stability and strength of thin-walled structures. doi
  42. (1985). Moment-rotation tests of steel bridge girders.
  43. (1989). Moment-rotation tests of steel girders with ultracompact Ranges.
  44. (1985). Note for Program MRFEB.
  45. (1963). On the collapse of composite beams. University of Cambridge.
  46. Plastic rotation of composite beams. doi
  47. (1979). Redistribution in composite beams,
  48. Research on steel-concrete composite beams. doi
  49. Rotation capacity of beams under moment gradient.
  50. (1987). Stabilisierung von Biegetragern durch Drehbettung eine Klarstellung. Der Stahlbau, doi
  51. (1991). Stability of composite bridge girders near internal support.
  52. Strength of continuous composite beams designed to Eurocode 4. doi
  53. Ultimate strength analysis of threedimensional braced I-beams. Proc, Instn Civ. Engrs, Part 2,1987,87,
  54. (1991). Ultimate strength of composite beams. doi
  55. (1990). Web-flange interaction in slender plate girders.

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