Strength of longitudinally stiffened webs subjected to concentrated loading

Longitudinal stiffening increases the ultimate strength of plate girder webs subjected to compressive edge load, commonly referred to as patch loading. This increase in most design codes has been disregarded. Therefore, this paper presents the background of three design models developed to quantify this increase in ultimate strength. The first model is based on the regression analysis of experimental results carried out around the world. The second is based on a modification of the yield line method used for unstiffened plate girders. Finally, the third one is based on a buckling curve approach. The third model is the most complete, accounting for stiffener properties, and also provides the best agreement with test results.