Constitutive Laws Assessment for Unconfined Concrete under Compression

Abstract

[EN] Nowadays, the rehabilitation of buildings takes more importance due to sustainability reasons. This involves working with existing building structures and the precise calculus of the building to guarantee the adequate strength and safety, from structures with change of use to deteriorated or damaged structures. Concrete is the most common material in building structures, but it is a heterogeneous and non-linear material. The concrete constitutive law, relation between strains and stresses in different directions, is very complex, and different in tension and compression. In the case of new construction project, the linear relationship between stress and strain has been proved safe enough, but it is unable to simulate the behaviour of used and damaged structures, where it is necessary to study the entire load range. In this work, the most widely used constitutive laws of concrete are compared, parameterizing the necessary constants for their professional application in advanced simulation structures software. Some of the evaluated constants are the Young's modulus, Poisson's ratio, stress cracking and crushing, failure energy or the law of damage evolution. Linear-multilinear behaviour, Willam-Warnke crushing and cracking criteria, continuum damage and microplane options are the assessed constitutive laws, showing the differences between the behaviour models and the tightest values of these material constants along the entire load range.