Incremental Approach to the Nonlinear Analysis of Reinforcement Concrete with Cracks at Plane Stress State

Incremental approach to the nonlinear analysis of reinforcement concrete with cracks at plane stress state is presented. Calculation method is based upon the N. Karpenko deformation model where the essential features of physical nonlinearity of reinforcement concrete such as acquired orthotropy of concrete, formation and propagation of cracks in tension concrete, yield of steel reinforcement are given serious consideration. Constitutional relations are set as relations between finite increments of strains and finite increments of stress at steps of load with regard to stage of material resistance and history of stress state. The proposed incremental modal with the finite element method were used for numerical analysis of experimental deep beams from NIIMosstroy investigation. As a result of calculation the modes of formation and propagation of cracks as well as deflation curves fully corresponding to the experiment data were obtained. Incremental approach has made it possible to substantially reduce the number of iterations at steps of load and is recommended for computer modelling of complicated space systems of buildings and structures.