Out-Plane Buckling Of Simply Supported Tapered Beam-Columns

Firstly, this paper presented an explicit rotation-deflection relation of tapered member based on numerical analysis, this relation is used to derive the rotational restraints provided to columns by the rafters in portal frames, the rafters may be composed of multiple segments of tapered members. These restraints are intended for employment in place of the APPENDIX D of the Code of Light-Weight Steel Portal-Frame(CECS 102:2002).Secondly, a finite-element formulation is presented for analysis of the inelastic flexural-torsional instability of non-prismatic beam-columns. The formulation represents a general approach to this problem.Thirdly,this paper reports an investigation into the elastic torsional buckling under axial load and elastic flexural-torsional buckling under eccentric axial force loads of web tapered I-section beam-columns.Several formulae for calculating buckling loads are presented to provide simple means of checking the out of plane stability of these kinds of members.Finally, research is conducted on the in-plane elastic stability of columns composed of several prismatic or tapered members under different boundary conditions,the results may be used for checking the stability of rafters when large axial forces exist in these members.