Study On Punching Shear Strength Of Reinforced Concrete Slabs

In recent years, the reinforced concrete slab-column structure has been widely used because of its unique superiority. Relevant research indicates that the strength of reinforced concrete slabs is generally controlled by the punching failure mode, which is mainly studied in this thesis.The theoretical methods for slab-column connections were discussed in this thesis, and nonlinear finite-element software Atena was used to study slab-column connections. Firstly, the constitutive model and fracture-plastic material model for concrete provided by the finite-element software Atena were described, and were proved valid by simulating the concrete under uniaxial tension and compression.Then, according to the derived carrying capacity, crack mode, crack position and developing condition, the famous Leonhardt’s shear beam and Bresler-Scordelis beam were applied to prove the simulation ability of Atena for brittle failure.Based on the conclusion above, finite-element analysis on one-way slabs and two-way slabs were performed, of which the results were compared with experiment results. The comparison shows that it’s feasible to simulate concrete slabs punching shear performance by nonlinear finite-element software Atena. The objective law of carrying capacity was analyzed by changing concrete strength grade, thickness of slab, ratio of reinforcement and load-carrying area separately.Based on129test data, taking several parameters into consideration, a regression formula was proposed by using the regression method.Then, punching strength of concrete slabs was analyzed by using three-parameter unified strength theory and limit equilibrium method, and a calculation formula was put forward.The comparison shows good agreement between the theoretical values and the finite-element analysis results. Suggestion formula was obtained from the finite-element analysis results by using regression method. Furthermore, reliability analysis was performed on the suggestion formula, and results shows that the suggestion formula can meet the requirement of the target reliability index3.7well in structural design code.