ABSTRACT
The capacity of horizontal failure shear keys is larger than diagonal and sliding failure modes owing to its secondary stiffness-strengthening stage. Nevertheless, the seismic performance of shear keys with horizontal failure mode has received limited attention yet. This investigation involved the design and fabrication of ten reinforced concrete (RC) exterior shear key specimens. A quasi-static experiment was conducted to assess the seismic performance of these shear key under cyclic load effects. The concerned properties include crack development, force-displacement relationship, rotation deformation and the stress distribution. The experimental results indicate that the failure mode is dependent on the capacity ratio between reinforcements. Horizontal failure shear key exhibits apparent second-rising of stiffness after its peak capacity, while the diagonal and sliding failure shear key undergo continuous decline under substantial deformations. Comparing the measured data with existing prediction models indicates that the models are more applicable to shear keys with diagonal failure mode as opposed to the others.
