Vierendeel Bending Study of Perforated Steel Beams with Various Novel Web Opening Shapes, through Non-linear Finite Element Analyses

The Vierendeel mechanism is always critical in perforated steel beams with single large web openings, where global shear forces and Vierendeel moments co-exist. Thus far, the main parameters that are known to affect the structural behavior of such beams are the depth of the web opening, the critical opening length of the top tee-section and the web opening area. A comprehensive Finite Element (FE) study of four sizes of perforated steel sections with three different sizes of eleven standard and novel non-standard web opening shapes was undertaken, and their primary structural characteristics presented in detail in order to provide a simple design method for general practice. The different geometric parameters were isolated and studied in order to understand the significance of their effects and in turn advance the knowledge on the performance of perforated steel beams. An elaborate FE model was established, with both material and geometrical non-linearity, allowing load redistribution across the web openings and formation of the Vierendeel mechanism. The reduction of the global shear capacities, due to incorporation of the local Vierendeel moments acting on the top and bottom tee-sections, was obtained directly from the FE analysis. Following that, a comparison of the global shear-moment (V/M) interaction curves of the steel sections with various web opening shapes and sizes was established and empirical generalized V/M interaction curves developed. Moreover, the accurate position of the plastic hinges was determined together with the critical opening length and the Vierendeel parameter. This work has now shown that the shape of the web opening can also significantly affect the structural behavior of perforated beams, as opposed to the equivalent rectangular shape predominately used so far. In addition, the effect of the position of the web opening along the length of the perforated beam was revealed. The importance of the parameters that affect the structural performance of such beams is illustrated. The thorough examination of the computational results has led to useful conclusions and an elliptical form of a web opening is proposed for further study. The outcome of this study is considered as being relevant for practical applications.