An appraisal of the compressive force path concept

Abstract

The results of an experimental appraisal of the compressive force path concept are presented in the form of a comparative study of the behaviour of beams reinforced in compliance with this concept and that of beams designed for shear in compliance with codal provisions based on the 45° truss analogy. The experimental results support the assertion of the compressive force path concept that the causes of failure of shear critical beams are associated with stress conditions in the region of the path along which the compressive chord force is transmitted to the supports and not with the traditional concept of shear capacity of a critical section. The experiments confirmed that although detailing of transverse reinforcement in the shear span of a beam following the recommendations of the 45° truss analogy will prevent a premature shear failure, such detailing in itself may not be sufficient to provide appreciable ductility to the member. Significant enhancement of ductility was observed in those beams in which the transverse reinforcement had been extended from the shear span into the flexure span in compliance with the compressive force path concept.