Transverse Stiffener Requirements to Develop Shear-Buckling and Postbuckling Resistance of Steel I-Girders

Abstract

Traditionally, the design of transverse stiffeners in the AISC and AASHTO specifications has been based on two criteria: a moment of inertia requirement to ensure near-zero lateral deflection of the stiffeners at the web shear buckling load, and an area requirement to ensure that the transverse stiffeners can serve as verticals in an effective Pratt truss in the postbuckling condition of the web. However, multiple investigators have found that the transverse stiffener response is dominated by bending actions caused by restraint of the out-of-plane deformation of the web panels. As such, the latest AASHTO and AISC specifications have adopted transverse stiffener sizing rules that focus solely on a transverse stiffener moment of inertia requirement. This paper summarizes various details of the underlying research leading to the development of these new rules and outlines the proper application of the new specification provisions.