Steel plate girder webs under combined patch loading, bending and shear

During bridge erection employing the incremental launching method, plate girders are subjected to a combined loading situation. Due to the support reaction, the thin webs are withstanding concentrated loads, and due to the self weight of the launching nose and the span between the piers the web is also under the action of bending and shear force. This paper is aimed at investigating the nonlinear behavior of unstiffened girder webs subjected to combined loading (concentrated loading, bending and shear) by using the finite element method. Firstly, the numerical models are validated against experimental results taken from the literature. Secondly, each individual resistance is calculated in order to normalize the applied loads. Thereafter, a parametric analysis is conducted looking at the interaction between the three types of loading, and a combined failure mode is identified. Finally, the results shows limits in the resistance when all three loads are applied.

► Interaction between patch loading, bending and shear in slender webs is investigated.
► A simplified finite element model is developed to investigate the interaction.
► The results are plotted in a 3D diagram showing some limits for this interaction.
► Failure of the girders is characterized by a combination of collapse mechanisms.