Abaqus; Strain; Umat;

Dear all,

I am using Abaqus to model concrete as an elastic material. However, the failure criteria available in the software is only for 2D elements and are dominated by a maximum normal stress (fail stress option) or normal strain (fail strain option) value.

I was wondering if anyone would know how to model concrete as an elastic material following "theory of elasticity" and failing by a maximum TENSILE strain value in any of the three directions given a material's point.