The third aim, is to study the free vibration, static buckling and dynamic instability of castellated beams, w subjected to transverse periodic loading by developing analytical solutions. The second aim, is to focus on the effect of both the geometric nonlinear and material inelasticity on castellated beams, under uniformly distributed load within different boundary conditions, through investigating the load-deflection curve and predicting the value of lateral-torsional buckling moment capacity, by using nonlinear numerical analysis method. The aims of this study are, firstly to investigate the effect of web openings on the transverse deflection and lateral-torsional buckling of castellated beams, by using both analytical and numerical methods, whilst also adopting some of the previous studies for validating the analytical results. However, for the buckling and calculation of serviceability, the shear weakness due to web openings in castellated beams, could affect the performance of the beams and thus needs to be carefully reconsidered. Design guidance on the strength and stiffness for castellated beams is available in most countries, but also, some of them do not take into account the shear effect because as far as the bending strength is concerned, neglecting the shear effect may not cause direct problems. However, previous studies confirm that the method of analysis and design for the solid beam, may not be suitable for the castellated beam. Therefore, web openings may reduce the shear resistance of the castellated beam. In addition, the fabrication process creates openings on the web, which can be used to accommodate services.Įxisting studies have shown that the resistance of the castellated beam is influenced by shear stresses, particularly those around web openings and under the T-section, which could cause the beam to have different failure modes.
This allows castellated beams to be used in long-span applications with light or moderate loading conditions for supporting floors and roofs. This process leads to increasing the beam’s depth and thus the bending strength and stiffness about the major axis, without adding additional materials. Most of the castellated beams are fabricated from a standard universal I-beam or H-column, by cutting the web on a half hexagonal line down the centre of the beam, then these two halves are moved directly across by a half unit of spacing and re-joined by welding. The castellated beam is one of the steel members which uses less material, but has equal performance as the I-beam of the same size.
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