Toward an Unified Compression Field Theory

Abstract

According to several Desing Codes as ACI-318 or EC-2, shear resistance of structural concrete elements (VR ) is composed by concrete contribution (Vc ) plus steel contribution (Vs ) and both of them are invariants related with the shear design (Vd ). Nevertheless a degradation process on VR appears as the shear deformation increases. Compression Field Theories are presented as a suitable way to explain this behaviour. This paper presents a detailed discussion on the different Compression Field theories for structural concrete. Modified Compression Field Theory is being widely used during the last years although it presents some inconsistencies especially in the treatment of the steel deformations. A new Compression Field Theory, the Unified Compression Field Theory (UCFT) is presented in order to differentiate the average steel stress and the local steel stress at the crack.