SHEAR-STRENGTH OF WEBS IN BOX-GIRDER BRIDGES

In a box girder the slenderness of the flanges is usually considered to be much larger than in a plate girder. As a result, existing calculation methods suggest neglecting the flange contribution to anchor the diagonal tension band and thus to the ultimate shear strength. Research carried out by the authors has demonstrated that this design approach is excessively cautious. In this paper a new simple semi-empirical method is proposed to evaluate the shear-carrying capacity of box girder webs with an aspect ratio up to 1.00. The effectiveness of the method is validated by the results of a series of experiments on models and by a comparison with other theoretical methods in evaluating the shear ultimate strength in the case of some real orthotropic deck bridges.