ABSTRACT
The equations for pure bending, pure shear, and pure torsion are all derived in a consistent and logical manner. Such clarity in concept makes the interaction of these actions relatively simple. These interaction relationships are discussed in this chapter. In the truss model, it is assumed that the axial tension is resisted only by the longitudinal steel bars. The 1978 Comite Euro-International du Beton (CEB)-FIP Model Code (or CEB Code) includes two design methods. The first is the "Standard Method", which is based on the traditional 45° truss model, modified by the addition of an empirical term attributed to the "contribution of concrete". The second, so-called accurate method is based on the variable-angle plasticity truss model. This second method is intended for the design of large girders, particularly those employed in bridges and guideways. The chapter introduces only the "accurate method". The CEB-FIP Code includes provisions for the design of beams with inclined web reinforcement.
