This article analyses the conditions for the yield stress state of concrete subjected to generalised loads. For this purpose, a limit stress state criterion, initially developed for the assessment of magnesium and respective alloys, is here adapted and implemented as a simulation model to assess the structural integrity of concrete components. In fact, materials as magnesium and concrete exhibit a similar mechanical behaviour, presenting a non-symmetric limit state domain for biaxial stress combinations, where it is observed a considerably larger strength to yield or rupture in a compression stress state than in a tensile one. The Cazacu yield stress state criterion has shown to be an accurate and realistic model to define the ultimate strength, either of concrete and magnesium alloys, as mentioned. The Cazacu criterion was implemented in a finite element program as a ‘user-defined’ subroutine. The numerical validation of that criterion was carried out on adjusting its limit stress state points to corresponding ones obtained by experiments of standard tensile or compression tests of concrete test specimens.
Nonlinear endochronic creep models taking into account the type of stress state
