Size effect on shear failure at core region of reinforced concrete connections: Experimental study

Fourteen geometrically-similar interior reinforced concrete (RC) beam-to-column connections whose maximum structural sizes were 700 mm×700 mm were designed. The seismic performances of these RC beam-to-column connections subjected to monotonic and low-cycle loading were tested. The effects of loading type, structural size and stirrup ratio on the shear failure behavior at the core region of the connections were studied. Moreover, the size effect on the nominal shear strength of the core region of RC connections was examined, and the sources of size effect were also discussed. The test results and analyses indicate that: (1) all the RC beam-tocolumn connections under monotonic and low-cycle loading failed by shear; (2) due to the existence of low-cycle fatigue damage characteristics, the nominal shear strength of the joints under cyclic loading is lower, and the deformation capacity is weaker; (3) the nominal shear strength decreases with the increase of the structural size of RC connections, and size effect phenomenon is obvious; (4) with the increase of stirrups ratio, the shear bearing capacity and deformation capacity of RC connections increases, at the same time the size effect in shear strength is weakened. In this experiment, the dominant effect of concrete failure and the low-cycle fatigue characteristic of loading are the main reasons for the size effect of shear failure. © 2019, Science Press. All right reserved.