OBTAINING THE CRITICAL SHEAR CRACK KINEMATICS FROM A MULTIACTION MODEL AND THE GRG METHOD

The behavior of concrete structures subjected to shear forces is a challenging topic for the scientific community. It involves the contribution of several shear force transfer mechanisms, such as aggregate interlock, dowel action, residual concrete tension, and uncracked concrete zone. The contribution and interaction between these mechanisms are dependent on the shape and kinematics of the critical shear crack. Such crack characteristics are influenced by the structural system and materials that compose the element. The prediction models have not considered all the mechanisms and have been mostly applied in reinforced concrete structures with steel bars. Therefore, this paper presents a multiaction model in which the referred mechanisms of shear force are also considered in the equilibrium of forces and moments, with the kinematics of the critical shear crack obtained from an optimization process using the GRG method. Numerical results of crack opening-slip, contribution of the transfer mechanisms, and values of critical rotation and neutral axis depth in the failure stage of the beam are presented.