Investigation of the Vierendeel Mechanism in steel cellular beams

Abstract

The presence of large web openings in steel cellular beams introduces complex local failure mechanisms that are not always accurately captured by current design provisions. In particular, the recommendations of EN 1993‐1‐13 regarding the Vierendeel mechanism have been reported to be conservative in certain configurations. This study investigates the Vierendeel mechanism in steel cellular beams at ambient temperature through advanced numerical modelling. A detailed finite element model, incorporating geometric and material nonlinearities as well as initial imperfections, was developed using shell elements and validated against experimental results of a cellular beam whose failure was governed by the Vierendeel mechanism. The numerical model accurately reproduced both the load–displacement response and the observed collapse mode. Based on this validated strategy, a simplified numerical model representing a single web opening was proposed and assessed using experimental data available in the literature. The results show that the simplified model reliably captures the governing Vierendeel behaviour with a significantly reduced computational cost, providing a robust numerical framework for future parametric studies and potential extensions to fire design.