Influence of cracked concrete models on the nonlinear analysis of High Strength Steel Fibre Reinforced Concrete corbels

In the present study, new material constitutive relationships for High Strength Steel Fibre Reinforced Concrete (HSSFRC) have been formulated by means of a regression analysis of many experimental data (available in literature) by using SPSS (Statistical Package for the Social Sciences) program. These proposed material constitutive relationships have been employed for formulating the material finite element models to study the behaviour of HSSFRC corbels.The corbel is considered in a plane stress state and an eight-node serendipity element has been employed to represent the concrete, a strain hardening plasticity approach is used to model the compression behaviour, the yield condition is formulated in terms of the first two stress invariants, a tensile strength criterion is used to predict crack initiation, two tensile stress degradation functions are used to model the tension stiffening. Five different cracked shear moduli have been compared in this paper.For plain high strength reinforced concrete corbels, the first tension stiffening (TS1) model with cracked shear modulus model (G¯4) and the second tension stiffening (TS2) with model (G¯2) give good results compared with experimental results.For HSSFRC corbels, the second tension stiffening (TS2) model with cracked shear modulus models (G¯2) and (G¯3) give good results compared with experimental results.The numerical results of the proposed material models and corbels behaviour compared with published experimental results showed good agreement.