Punching Shear Capacity Analysis Of Concrete Slab Based On The Three-parameter Unified Strength Theory

So far, the flat-plate structure has been widely used in multi-storey factory buildings, warehouses, the public buildings halls as many advantages. However, slab-column connections in plate structures came to bear a larger concentration from plate. Thus the connections are susceptible to punching shear failure, Since punching shear failure is a typical brittle failure, it will cause the separation of slab and column and might even cause progressive collapse of the whole structure. Many researches have been focused on this problem.In this paper, Punching shear capacities have been investigated for reinforced concrete slab and the unbonded pre-stressed reinforced concrete slab based on the three-parameter unified strength theory, The numerical models have also been established and the punching shear capacities have been simulated using finite element simulation. The main contents are listed as follows:In this paper, some common codes and the analysis methods for punching shear of the concrete plate have been reviewed firstly. The punching shear failure mechanism has been analysed. The main factors influcing the punching shear capacities have been studied according to previous literatures and the failure process.The flexural capacities for the concrete circular and square plate have been obtained based on yield line theory. The punching strength of the reinforced concrete slab is then analyzed in this paper based on the three-parameter unified strength theory. The problem is treated as a three-dimensional axisymmetrical one, the material being assumed to be rigid-plastic. The formula of the punching strength for reinforced concrete slab is derived. Based on the above work, the ultimate punching shear strength of the unbonded pre-stressed reinforced concrete slab is obtained by being equivalent the effective pre-stress to the external forces acting on the plate.The punching shear performance on the above two types of plate is simulated using the commercial finite element software ANSYS. The crack development situation and the punching shear capacities of slab are obtained. Parametric studies have been carried out to investigate the influences of concrete strength, the reinforcement ratio, different way of pre-stressed reinforcement. Good agreement can be observed by comparison with test data.