Principles of Building Structure - Essay Example

When the beam has sufficient supported against any form of buckling, a failure of the beam is experienced. This results in the generation of the maximum material yield at one point of the maximum moment (Brett 1989). Hence, the applied loads have the potential of ensuring that the beam reaches its plastic moment capacity. This beam is regarded as laterally supported beam and the yield stress governs the design strength. When beams bend on a major axis, they tend to develop a stronger stiffness and strength.

Thus, such beams become vulnerable to failure that results from lateral torsional buckling before they acquire their in-plane capacity of the plastic moment, which will brace them against lateral twisting and deflection. These types of beams are regarded as laterally supported beams. Beams bending strength design is governed by yielding and supported against buckling. A laterally braced section of a beam has a bending strength, which is the plastic moment Mp. Inelastic deformation is expected at the service load when the shape factor of the beam is large.

However, for shape factors that exceed 1.5, 1.5My limit is applied at the factor load in order to control the inelastic deformation of the various sections of the beam. Such a provision is not expected to limit the plastic moment for the hybrid section when the yield stress is considered to be less than the expected flange yield stress. However, web yielding is not associated with any significant inelastic deformations. When the inertia moment about the axis of bending is less or equal to the out of plane inertia moment, lateral-torsional buckling never develops.

Therefore, for shapes, which are bent within the minor axis and those that have lz = ly, lateral-torsional buckling limit state does not apply. Such shapes include circles and squares. Lateral buckling of a beam does not occur when the compression of the flange is adequate and the flexural