VI CONGRESS 1/10 Research and development ASSESSMENT OF PRESTRESSED CONCRETE BRIDGE GIRDERS WITH LOW SHEAR REINFORCEMENT BY MEANS OF A NONLINEAR FILAMENT FRAME MODEL Denise SANTOS FERREIRA Doctora Ingeniera Civil Universitat Politècnica de Catalunya Investigadora denise.carina.santos@upc.edu Antonio R. MARÍ BERNAT Doctor Ingeniero de Caminos Universitat Politècnica de Catalunya Catedrático de Universidad antonio.mari@upc.edu Jesús M. BAIRAN GARCIA Doctor Ingeniero de Caminos Universitat Politècnica de Catalunya Profesor Agregado jesus.miguel.bairan@upc.edu SUMMARY The safety of existing bridges can be studied through nonlinear numerical models, assisting decisions of dismantle, repair or change of use and avoiding unnecessary or inappropriate interventions. Filament beam models due to their simplicity and low computational demand are adequate for the engineering practice as an alternative to 2D and 3D FEM. In this communication, the structural assessment of a prestressed concrete bridge with low shear reinforcement - the Wassnerwald Viaduct in Switzerland – is presented. The bridge was dismantled due to, among other reasons, not complying with the shear safety standards. The girders of the bridge, which were submitted to full-scale in situ load tests, were numerically simulated by means of a nonlinear filament beam model considering axial force–shear–bending interaction recently developed by the authors. Hypothetical strengthening solutions with external prestressing were also studied. KEY WORDS: Structural assessment, Strengthening, Shear, Nonlinear analysis, Fibre beam model.