SHEAR-STRENGTH OF WEBS IN BOX-GIRDER BRIDGES

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