Deflections of Composite Beams with Web Openings

Abstract

Procedures for calculating the deflections of composite beams with web openings are described. Initially, a matrix formulation is used. Modeling assumptions are verified by comparison with experimental data, and recommendations for practical application of the matrix analysis procedures are made. The results of the comparison are used to develop a design aid for estimating the maximum deflection of beams with web openings and an expression for calculating the deflection across a web opening. The work demonstrates that, in most cases, a single web opening often has little effect on the total deflection of a composite beam. There are, however, important cases where the effect can be significant. The effects of an opening and of shear deflections are of the same order. Ignoring both the web opening and shear deformation can lead to significant error. The matrix stiffness method, the design aid, and closed form equations provide reasonable estimates of both total deflection and deflection across an opening.