| The shear capacity of reinforced concrete members subjected to monotonic loads was investigated and used as the basis to formulate an expression to calculate the strength of members subjected to load reversals.; The monotonic shear capacity of slender beams, deep beams, walls, and columns was calculated by superposition of components related to arch-action, truss-action, friction, and from a contribution of the uncracked compression zone, which is related to the tensile strength of concrete. A procedure to calculate the shear strength of members in the transition phase from deep to slender members was formulated, so that the proposed expression can be used for all geometries considered. The shear strength of members with and without web reinforcement was analyzed. The proposed model was calibrated using an extensive database of test results, and was found to give good results compared to other analysis models in an n-fold cross validation.; The resistance to lateral load reversals was investigated for two failure modes: failure due to degradation of the flexural strength, and failure due to degradation of the shear strength. The degradation of flexural strength is expressed in terms of a linear slope derived from the displacement and load at yielding of the tensile reinforcement to the displacement at 80 percent of the yield load. Shear failure was defined by yielding of the transverse reinforcement. The degradation of shear strength was found to be non-linear with respect to the limiting displacement, and is formulated as a reduction factor for the initial shear strength. Degradation functions for the decrease in strength of the contributing arch and compression zone components, and for the truss mechanism are presented. |
