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

Abstract

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. This study provides essential insights into the behavior of steel and steel-concrete composite plate girders given web shear buckling conditions. The findings have practical implications for engineers and practitioners in the field of structural engineering, particularly those involved in the design and assessment of bridge girders and other large-scale structures. The research highlights the increased shear resistance and load-carrying capacity of composite plate girders compared with those of steel girders. The contribution of the concrete slab to the overall shear stiffness and the effective transfer of forces through shear studs are key benefits that can enhance the design and longevity of composite structures. By understanding these mechanisms, engineers can optimize the design of composite girders to achieve higher performance and safety standards. Additionally, this study reveals the significant influence of web slenderness and the aspect ratio on the ultimate load capacity, emphasizing the need for the accurate consideration of these factors in design codes. The findings suggest that current European design codes could be improved by incorporating more advanced analytical models that account for the concrete slab’s contribution and composite action. Overall, this research underscores the importance of considering composite action in girder design and provides a foundation for future improvements in structural design codes, potentially leading to more efficient and resilient infrastructure.