FE model of each specimen that is utilized in the experimental studies is carried out. The finite element method has been used to predict their entire response to increasing values of external loading until they lose their load carrying capacity. The objective of this study is to carry out non-linear finite element (FE) analysis of the cellular beams that were considered in the experimental study in order to determine their ultimate load carrying capacity for comparison. The purpose of manufacturing these beams is to increase the overall beam depth, the moment of inertia and section modulus, which results in greater strength and rigidity. Their sophisticated design and profiling process provides greater flexibility in beam proportioning for strength, depth, size and location of circular holes. Therefore, a general equation is proposed to determine the value of optimum stiffness (kopt) in terms of the beam’s slenderness, applicable to all castellated beams under pure bending.Ĭellular beams became increasingly popular as an efficient structural form in steel construction since their introduction. Also, the results show that Winter’s simplified method to determine full brace requirements cannot be applied to inelastic castellated beams. In other words, the effect of bracing depends not only on the stiffness of the restraint but also on the modified slenderness of the beam. It was found that for inelastic castellated beams, the effect of bracing initially is increased to some extent as the lateral unbraced length increases and then decreased until the beam behaves as an elastic beam. This paper develops a three dimensional (3-D) finite-element model using a finite-element program and uses it to investigate the effect of elastic lateral bracing stiffness on the inelastic flexural–torsional buckling of simply supported castellated beams with an elastic lateral restraint under pure bending. However, a full study of the effect of lateral braces on inelastic buckling has not been made especially for castellated beams, and it is not known whether the limiting stiffness for elastic buckling can be applied to castellated beams that buckle inelastically. It is well known that an elastic lateral brace restricts partially the lateral buckling of slender beams and increases the elastic buckling moment. Bracings are usually assumed to be elastic, and so may be characterized by their elastic stiffnesses. Lateral–torsional buckling can be avoided by properly spaced and designed lateral bracing.
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