Experimental Study On Shear Failure Of One-way Slabs

In recent years, the reinforced concrete slab-column structure with its unique superiority has been widely used. But it is a fact that the load capacity of slab-column structure is often controlled by the punching failure of slab-column connections. However, the mechanism of punching failure is still not clearly explained. Since the punching failure of slab-column connections and the shear failure of one-way slabs have a lot in common, it is usually considered that the theoretical explaination of punching failure is closely linked with shear failure mechanism of one-way slabs.As punching test often loaded through stub, shear test often loaded through one point or two points on the upper surface of specimen, the existing shear test results and punching test results can not contrast directly. Based on this, a total of22one-way slabs are tested, and the influence of stub on the shear failure is analyzed by test results, including the load-deflection curves and load-strain curves. Meanwhile, variables such as reinforcement ratio (ρL,ρH), shear span ratio (3,5,7) and concrete strength grade (C30,C50) are considered in this experiment. This experimental research lays the foundation for the following comparison of punching failure of slab-column connections and shear failure of one-way slabs.After calculating the shear capacity of specimen according to modified compression field theory, compressive-force path theory, critical diagonal crack width theory and splitting failure theory, a theoretical model is established based on the first stage of splitting failure theory. This model takes into account the shear deformation of longitudinal reinforcement and the development of critical diagonal crack along the second stage at ultimate state, and considers that the final failure of specimen is caused by the shear failure of shear compression zone along the critical line. The shear capacity formula derived from this model can accurately predict the shear test results of651beams without web reinforcement, therefore it can be used as shear strength prediction formula.