International journal of steel structures (국제강구조저널)

Korean Society of Steel Construction (한국강구조학회)
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Contribution of the Flexible Supports to the distribution of the Internal forces in Steel Frames

  • Stamatopoulos, George N. (Laboratory of Metal Structures, School of Civil Engineering, National Technical University of Athens)
  • Received : 2012.05.03
  • Accepted : 2012.08.29
  • Published : 2012.09.30
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Abstract

In this paper, the contribution of the flexible supports to the overall frame response and internal forces distribution is examined. Two types of a two-bar typical frame are considered, subjected to vertical uniformly distributed load q on the beam and concentrated load P at the top of the column. In the first frame under examination, the free end of the beam is pinned, while in the second frame the free end of the beam is horizontally sliding, representing the cases of nonsway and sway mode respectively. To incorporate the effect of semi-rigid supports' flexibility, the column base support is simulated with nonlinear springs, representing the moment-rotation (M-${\Theta}$) behaviour and the foundation rotational and tranlational stiffnesses as well. The non-linear equilibrium systems of both nonsway and sway frames in their deformed state are formulated, and the internal forces and the rotations and displacements of the joints are obtained. From the obtained distribution of the internal forces that act in the members of the frames examined, it could be concluded that the influence of the flexible supports should be always taken into account in design practice, since this consideration leads to important economy and to a more realistic determination of the safety of structures.

Keywords

References

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