Buckling Properties of Monosymmetric I-Beams

Approximations are derived for the section properties required for the calculation of the elastic critical loads of monosymmetric I-beams and are found to be related to the ratio of compression flange and section minor axis second moments of area. Approximations are obtained that are applicable to I-sections with unequal and lipped flanges and that are in close agreement with accurate calculations of the monosymmetry section properties made for a wide range of cross sections. An improved design rule is proposed for the elastic critical stress of a monosymmetric I-beam. A comparison is made of the results obtained using the proposed rule and the present rules of the AS 1250, BS 449, and AISC Specification

Elastic Behavior of Tapered Monosymmetric I-Beams

The simultaneous differential equations for bending out of the plane of symmetry and for torsion of tapered monosymmetric I-beams are derived by considering the flange displacements. It is found that these equations are not independent because the shear center and the longitudinal centroidal axes are not parallel, and it is concluded that torsion is always accompanied by bending out of the plane of symmetry. The bending and torsion equations simplify considerably for the particular case of tapered monosymmetric I-beams of constant depth. The elastic stability of tapered monosymmetric simply supported I-beams of constant depth with central concentrated loads acting in the plane of the webs is also investigated both theoretically and experimentally. The governing differential equations for bending and torsion are solved numerically by the method of finite integrals