Lateral–torsional buckling resistance of corrugated web girders based on deterministic and stochastic nonlinear analysis
Erzsébet Bärnkopf, Bence Jáger, Balázs Kövesdi
Abstract
There is no commonly accepted and reliable design method to determine the lateral–torsional buckling (LTB) resistance of steel trapezoidally corrugated web girders. Therefore, the focus of the current paper is on the investigation of this failure mode, detailed evaluation of the structural behavior and determination of the accurate LTB resistance. An advanced finite element (FE) model is developed and validated using the results of laboratory test performed at the Budapest University of Technology and Economics in 2018. Based on the experimental background virtual tests are performed on a simply supported beam subjected by pure bending moment. The effect of the different flange sizes, corrugation layouts, boundary conditions and steel grade including high-strength steel as well, are investigated. Two kinds of parametric studies are performed using (i) deterministic and (ii) stochastic nonlinear analysis. In both cases the imperfections have a key role in the FEM-based resistance calculation. Therefore, the imperfections are considered as initial geometric imperfections and residual stress, and also as equivalent geometric imperfections and their results are compared. The required equivalent geometric imperfection magnitude is determined and proposed in such a way to achieve the same impact as the initial geometric imperfection and residual stresses have. By both the deterministic and stochastic analysis results the required buckling curve of the Eurocode is determined by reliability assessment. The results of the two different analyses are compared and design recommendation is given for reduction factor determination for trapezoidally corrugated web girders.