REDEFINING THE SHEAR CAPACITY OF STEEL PLATE GIRDERS BASED ON RECENT SHEAR MECHANICS AND AN EXTENSIVE NUMERICAL INVESTIGATION

Abstract

Many bridges are built with steel plate girders that consist of thin webs, flanges, and stiffeners engineered to withstand significant shear loads. It is well-known that thin web plates are prone to buckling under shear loads, leading to reduced strength. However, recent research has challenged the shear mechanics used in existing design codes and standards to determine nominal shear capacity. The first objective of this thesis is thus to redefine “shear capacity” based on recent mechanics/behavior research and an extensive numerical study that uses 930 examples of plate girder panels fabricated/built in the last 10 years. Experimentally validated finite element models, and recent research on web shear buckling mechanics are employed to define and capture the shear strength thus creating 930 data points. The significance of this first objective is that it permits using extensive, proper and consistent data for developing models that predict shear capacity, which is the second objective of the thesis. This data is then used to develop alternative equations for predicting the shear capacity of steel plate girders, where the alternative equations are shown to have a better fit to the data than the existing codes and standards.