Rectangular stress block factors for high strength confined concrete

Abstract

In this paper, simplified expressions for stress block factors that define equivalent uniform stress distribution and for the ultimate concrete strains are proposed. These expressions have the compressive strength and the confinement of concrete as variables, and are valid for instantaneous loads, concrete strength between 25 and 80 MPa and reinforcement ratio of confinement up to 4%. These expressions have been derived on the basis of the constitutive equation for concrete proposed by Yazzar (2000). The model proposed in this paper has been checked with the results from 164 experimental tests carried our by several researchers, getting a good accuracy.