APPLICATION OF NLFEA TO CONCRETE STRUCTURES.

Nonlinear finite element analysis (NLFEA) systems are rarely used in practice for the analysis of concrete structures even through several systems have been developed to date. The main reason appears to be a lack of agreement concerning the numerical description of material behavior characteristics. A successful NLFEA system is developed by incorporating realistic descriptions of material characteristics into a basically standard nonlinear finite element package. The system applies to the analysis of concrete structures under short-term plane stress and axisymmetric loading conditions. Simple, yet realistic, numerical models are presented to describe important features of material behavior such as failure criteria and deformational properties of concrete and steel, fracture processes of concrete and steel-concrete interaction. Procedures to represent crack propagation in concrete appear to influence significantly the quality of predictions. Three structural configurations of known experimental performance are finally analyzed.