IMPROVING THE STRUT AND TIE METHOD BY INCLUDING THE CONCRETE SOFTENING EFFECT

Strut and tie model approach evolves as one of the most useful analysis methods for shear critical structures and for other disturbed regions in concrete structures. The main objective of this research is modified the strut and tie method. As especially of the softening strut and tie method, the following work concern for determining a new factor (named-correction factor λ), and the formulation is based on the failure criterion from the Mohr Coulomb Theory for nodal zones (tension-compression stress state). To support the theoretical work eleven simply supported reinforced concrete deep beams have been casting and testing. The parameters considered in this study are; shear span to total depth (a?h), compressive strength of concrete (f_c^'), vertical web reinforcement (ρ_v) and horizontal web reinforcement (ρ_v). The effect of these variables on the; cracking load, ultimate load, load-midspan deflection response, crack pattern, and strains of concrete and steel reinforcement have been studied. According to the experimental results, a relationship between the correction factor (λ) and the variables (shear span to total depth ratio, concrete compressive strength, vertical web reinforcement and horizontal web reinforcement? was assumed.