Shear capacity of a reinforced concrete frame joint subjected to arbitrary horizontal loading

Earthquake action is multi-dimensional and random. The anti-seismic capability of beam-column joints in reinforced concrete (RC) frame structures under arbitrary horizontal direction loading may be lower than the design capability for unidirectional earthquake actions. To date, detailed calculation methods for the shear capability and shearing performance of joints in RC frames under arbitrary horizontal direction loading have not been reported. For this reason, in this work, the shear mechanism of beam-column joints in an RC frame under arbitrary horizontal direction loading is analysed. This study shows that two oblique compression zones form at the corners of the joint when a synthetic shear force is imposed on the joint, and an oblique compression strut is formed in the core area of the joint, which is different from the shear mechanism of a joint under unidirectional loading. Furthermore, a shear capacity calculation model is established based on the strut-and-tie model. The predicted values of the shear capability in this work are in good agreement with the reported experimental results.