Certain parts of structures are designed with almost exaggerated accuracy while other parts are designed using rules of thumb or judgment based on past experience. However, all parts of a structure are of similar importance. A unified design concept, which is consistent for all types of structures and all their parts, is required. To be satisfactory, this concept must be based on realistic physical models. Strut-and-tie-mode Is, a generalization of the well known truss analogy method for beams, are proposed as the appropriate approach for designing structural concrete, which includes both reinforced and prestressed concrete structures. This report shows how suitable models are developed and proposes criteria according to which the model's elements can be dimensioned uniformly for all possible cases. The concept is explained using numerous design examples, many of which treat the effect of prestress. This report was initially prepared for discussion within CEB (Comitd Euro-International du Beton) in onnection with the revision of the Model Code,
