Toward a unified nomenclature for reinforced-concrete theory

Research in the fundamental behavior of reinforced concrete has progressed greatly since the 1960s, particularly in the areas of shear and torsion. This large body of knowledge spawned many theories and created many terms that do not adhere to a centralized nomenclature-a very confusing situation for the engineering profession. This paper proposes a unified nomenclature that covers all four basic actions (bending, axial load, shear, and torsion) and is based on the angle of inclination of the concrete struts, the scope of applications, and the three fundamental principles of the mechanics of materials (stress equilibrium, strain compatibility, and the constitutive laws of materials). Six models are presented: strut-and-tie model, Bernouli compatibility truss model, equilibrium (plasticity) truss model, Mohr compatibility truss model, softened truss model, and fixed-angle softened-truss model. This paper shows that all rational reinforced-concrete theories developed to date can be covered by these six models.