Novel simplified equations for Vierendeel design of beams with (elongated) circular openings

摘要

The Vierendeel bending is the dominant failure mode of steel beams with openings. The Vierendeel mechanism involves three interacting drivers, namely the axial force, the shear force and the Vierendeel bending moment This study proposes an alternative design method to check for the Vierendeel failure of non-composite symmetric cellular beams, or steel beams with circular or elongated circular openings. The method is based on a quadratic nonlinear failure criterion, using normalized driving forces, their simplified actions, and an approximate critical section location and angle. Accuracy of the method is assessed with 20 literature curated experiments. In addition, based on a parametric simulation study, the normalized moment-shear-interaction curves obtained from the proposed method agree well with these curves from finite elements (FE). Compared with the FE shear loads at failure, the designed shear loads calculated based on the member resistances recommended in both BS EN 1993-1-1 and ANSI/AISC 360-10 are conservative. However, for steel beams with elongated circular openings, using the resistances based on the BS EN 1993-1-1, the proposed design improves the accuracy by about 16% on an average relative to the SCI P355 method. In relation to other currently available design approaches, the proposed method is a simpler alternative for the Vierendeel bending check. No nonlinear reduction of the web thickness, to account for high shear, is required. Furthermore, the method simultaneously addresses the combined global bending from flexure, shear and Vierendeel. The proposed method thus facilitates safe and cost-effective design of beams with openings. (C) 2015 Elsevier Ltd. All rights reserved.