Web Shear Buckling of Steel-Concrete Composite Girders: Large-Scale Experimental Study

This study introduces a large-scale testing campaign on five suitably sized steel and steel-concrete composite plate girders subjected to web shear buckling. The focus of this investigation is on understanding the structural behavior of composite plate girders, the contribution of the concrete slab, and the composite action on the phenomenon of web shear buckling with almost no influence of the bending moments. Implementing an antisymmetric loading scenario, along with comprehensive state-of-the-art optical measurements, reveals that the overall shear resistance increased because of the concrete slab. These findings indicate that the current European normative rules require the application of a more advanced analytical model to provide accurate design results. Furthermore, although the influence of web slenderness and the aspect ratio is significant, the degree of shear connection is shown to have less of an impact on the ultimate load in plate girders in shear. Moreover, this study examines not only the overall structural behavior of composite plate girders but also delves into the deflected shape of the web panel, the formation and development of the tension field in the web, the creation of plastic hinges in the flanges, and the crack development and failure in the concrete slab. The aforementioned aspects help unveil the ambiguity behind the phenomenon of shear buckling in composite plate girders.