Design of steel plate girders subjected to shear buckling at ambient and elevated temperatures: Contribution from the flanges

Eurocode 3 (EC3) states that the shear design resistance of a plate girder is given by the sum of the web resistance and the flanges contribution, being these calculated separately. The accuracy of these provisions is normally assessed by comparison with the results of numerical simulations using numerical models duly validated with experimental tests. However, the web resistance alone cannot be directly obtained by the numerical model. The usual procedure is to calculate the numerical resistance of the web by subtracting the flange contribution, obtained using the EC3 expression, from the ultimate shear strength directly predicted by the numerical model. Consequently, the accuracy of the EC3 expression to predict the flanges contribution may influence this assessment. Hence, the accuracy of the EC3 design expressions to calculate the contribution from the flanges to shear buckling is evaluated here. An improvement on the calculation of the distance c, which defines the position of the plastic hinges that forms in the flanges, is proposed. The ultimate shear strength predicted by EC3 has been compared with numerical results at both ambient and elevated temperatures, considering the original and proposed values for the distance c.