ANONLINEAR ANALYSIS OF FIBROUS REINFORCED CONCRETE SLABS BY ASSUMED STRAIN AND HETEROSIS ELEMENTS

Abstract

AbstractIn the present work, the finite element method has been used to investigate the behavior of fibre reinforced concrete slabs in the pre and post-cracking levels up to the ultimate load. Assumed transverse shear strain is used in the formulation to overcome the shear locking, and Heterosis elements are employed in the analysis. Both an elastic-perfectly plastic and strain hardening plasticity approach have been employed to model the compressive behavior of the fibre concrete. The yield condition is formulated in terms of the first two stress invariants. Concrete crushing is a strain-controlled phenomenon, which is monitored by a fracture surface similar to the yield surface. A layered approach is adopted to discretize the concrete through the thickness. A tension stiffening model has been suggested by making a regression analysis of the experimental results, with index of determination (90.61%). The steel is considered either as an elastic perfectly plastic material or as an elastic-plastic material with linear strain hardening. Steel reinforcement is assumed to have similar tensile and compressive stress-strain relationship.Keywords: Finite Element Method, Slab, Steel Fibre Reinforced Concrete, Tension