Concrete01, Concrete02, Concrete03, Concrete04 -- Material Behavior

Each material was subjected to a series of ten uniaxial tension and compression strain histories. The following is the response of this material to such strain excursions. The data shown are the normalized stresses versus strain. In the normalization, the steel stress was divided by the yield stress Fy and the concrete stress was divided by the absolute value of compressive strength fc -- to maintain positive tension and negative compression. The first figure shows all 10 load patterns together, which are subsequently shown individually.

A comparison of all material behaviors shows that while the static-pushover response of the three materials is the same in compression, the stress-strain response of the materials is different in the tensile-strain region, as expected by the definition of the materials. The other evident difference between the concrete materials lies in the inelastic unloading and reloading curves. While Concrete02 has some hysteretic unloading/reloading branches, Concrete01, Concrete03 and Concrete04 do not.

As shown in the figures, Concrete04 has a different type of backbone curve, as this material attempts a closer representation of the Mander Model.