Biaxial Shear in Reinforced Concrete Beams and Columns

Interaction between multi-directional shear forces in reinforced concrete (RC) members is understudied in literature. Nevertheless, this loading condition can commonly occur in columns and walls of buildings subjected to horizontal forces. Moreover, most design and evaluation methods reported in codes do not consider any interaction between the shear strength in the two principal directions of inertia. An exhaustive state of the art of available experimental data on beams and columns tested under bi-axial loading is reported in this paper. Afterwards, the results of an experimental program on ten beams, with rectangular section, subjected to inclined shear is presented. The carried out experimental campaign aims to fill the lack of data on concrete members characterised by rectangular sections and reinforced with rebar and stirrups configuration typical of existing buildings. An analytical formulation was proposed, with the aim to extend the prescriptions presented in the fib Model Code 2010 to the biaxial shear force. Finally, a case study of an existing building located in Italy will be provided to demonstrate the effects of biaxial shear interaction on verification of RC columns.