Material definition effect the shear and stiffness degradation; try Maekawa-Fukuura concrete model, JSCE tension stiffening, JSCE plasticity with interface element. Beside instead of using reinforcement grid, use individual bars.

thank you very much for the guidance. kindly guide about the individula bars modelling please

further while modelling infill, i get this kind of graoh with the curve not getting down. what could be reason for this. i have used engineering masonry model, now using modhr-coulomb druger prager but still no improvement