Experimental study and kinematics-based approach for shear strength assessment of RC corbels with variously inclined reinforcement

Reinforced concrete (RC) corbels are widely used in precast concrete connections due to their structural efficiency and ease of construction. However, many existing RC corbels containing reinforcement with different inclinations that do not comply with the current design codes are facing increasing maintenance challenges. An appropriate assessment of their shear strength is essential to extending and preserving the life of the entire structure. This paper investigates the crack formation and shear failure of RC corbels with variously inclined reinforcement and without web reinforcement and through an experimental program consisting of six large-scale tests. The main variables are the reinforcement inclination, the shear span-to-depth ratio and the impact of preset inclined cracks at the corbel corner. The detailed test results on the shear strength, crack kinematics and rotational deformations are also presented. Subsequently, a kinematics-based discontinuous field approach is developed to study the rotational and translational mechanisms of shear resistance of RC corbels. A comparison with an extended test database from the literature then shows that the proposed approach has a fairly good agreement over existing cantilever beam methods and strut-and-tie models. Finally, the physical role of the inclined reinforcement, the influence of corner cracks, the application limitations and future work of the proposed approach are discussed. This solution provides a clear explanation of the failure mechanisms toward rapid shear strength assessment of existing RC corbels in the maintenance and strengthening. • A simplified shear strength approach is developed for RC corbels with variously inclined reinforcement. • The crack formation and shear failures of RC corbels are demonstrated experimentally. • Kinematics-based discontinuous field analysis is advocated for shear strength assessment of RC corbels. • Two rotational and translational failure mechanisms are identified by the crack kinematics.