Semi-discrete finite element analysis of slab-girder bridges

A semi-discrete finite element formulation is presented for the bending analysis of eccentrically stiffened plates and slab-girder bridges subjected to transverse loads. The plate and stiffeners are modeled by plate and beam elements, respectively. The extensional displacements reflecting the plate-stiffener interaction in the plate and beam elements are approximated in terms of the bending deformations. This is accomplished by modifying the flexural rigidities of the plate and stiffeners based on the integration by which the internal forces were derived from the internal stresses. This alleviates the need for the extensional degrees of freedom for the plate and beam elements. Consequently, the formulation is considerably simplified and the resulting model is computationally efficient. The numerical results are compared with those obtained by other methods. It is demonstrated that the proposed simplified model can satisfactorily predict the response of stiffened panels with moderately spaced stiffeners such as bridge decks.