<p>Nowadays a bridge design tool has to integrate all operations in the design process, such as architectural modeling, construction planning and management, structural analysis, member design, and detailing. An essential part of the member design is the assessment and proof of the safety of prestressed concrete sections based on national standards. Prestressed and reinforced concrete elements resist tensile and shear forces, bending, and torsional moments. The actions are coupled, and cracks occur due to tensile stresses. This results in a non-linear response of cross- sections. The complexity of the problem is multiplied by the arbitrary shape of the bridge sections. The objective of the paper is to describe a general method for the assessment of the resistance of reinforced and prestressed concrete cross-sections subjected to a coupled action of internal forces. The assumptions of the models adopted in the currently valid EN and AASHTO codes are analyzed, appropriate numerical methods are developed, and the resulting values of strength and response of the sections are compared for several examples.</p>