Nonlinear finite element analysis of reinforced concrete structures with a particular strategy following the cracking process

Abstract

A computer program is developed for the finite element nonlinear analysis of two-dimensional reinforced concrete structures under monotonic loading. The smeared crack approach is used and the reinforcement is considered uniformly distributed within the element. An elastic work-hardening plastic stress-strain relationship with a nonassociated flow rule is assumed for the concrete in compression and elastic brittle fracture behaviour in tension. The steel is considered as an elastic-perfectly plastic material. Nonlinear reversible formulations are used for the tension stiffening and the aggregate interlock, while a linear model is adopted for the dowel action of the reinforcement. The overall behaviour of a cracked element is obtained by combining the above phenomena in such a way that the normal and tangential effects are coupled. A new solution algorithm is developed, with a variable load level, which follows the subsequent cracking of elements. Therefore a better approximation of the response of the cracked structure, highly path dependent, is obtained. Numerical examples are presented and a comparison is made with experimental results. A good agreement is observed and many aspects of the behaviour of the structures are well represented by the analysis.