Ultimate shear strength of steel plate girders at normal and fire conditions

Shear buckling resistance is one of the most important load cases to be considered when designing steel plate girders with slender cross-sections. However, there is a lack of guidance for the fire design of steel plate girders subjected to shear buckling. After the evaluation of the contribution from the flanges to shear buckling resistance in previous works, an extended numerical analysis has been carried out, dealing with the evaluation of the shear buckling resistance of steel plate girders at both normal and elevated temperatures. The numerical results have been compared with those obtained from the application of the Eurocode 3 (EC3) design expressions. A methodology for analysis of the results, which considers three failure zones based on shear-bending interaction diagram, has been used in order to compare the numerical results with the analytical expressions. Moreover, maintaining the EC3 principles, a new expression for the contribution from the web to shear buckling resistance is presented for both normal and elevated temperatures. Finally, a study on the influence of the girders geometrical relations on the increase of strength provided by the rigid end post has been performed.