A NEW SIMPLIFIED MODEL FOR NONLINEAR RC SLABS ANALYSIS

A new technique for nonlinear analysis of reinforced concrete (RC) sla bs under various lending programs is developed. The technique is based on nonlinear finite element (FE) analysis of a grid representing the slab. All original formulation for the representative grid allows a go od quality of the representation for the most coarse mesh of the grid awes. A refined nonlinear FE model of a RC frame under complex loading was used. The model is based on a new modification of spatial anisotr opic beam finite element and refined constitutive models of concrete a nd steel-in-concrete under complex loading history. The developed simp lified method is capable of predicting nonlinear behavior up to the fa ilure for various RC slabs subjected to monotonic and complex lending (including unloading and reloading branches). Slabs with different bou ndary conditions, geometry,, reinforcement, and material properties ca n be analyzed. Membrane action and influence of nonideal boundary cond itions are treated. Analytical results for various RC slabs rested by different investigators under different programs show a good agreement with the experimentally observed data.