Comparative Research On Punching Shear Failure And Shear Failure Of Reinforced Concrete

The slab-column structure has becoming more increasingly applied in nowaday projects because of its flexible spatial arrangement,direct force transmission and clear height increase of floor.At the same time,the mechanical performance of itself has drawn more and more attention of the researchers at home and abroad.It’s fund that the weak point of the structure is the punching shear failure occurred at the slab-column connections.The punching shear failure is brittle failure without symptom and can arouse a series of reaction which lead to the collapse of the whole structure.As a result,the keypoint of popularize the structure is how to avoid punching shear by enhancing its punching resistance performance.Based on the existing work,the systematic research is done to analyse the punching shear behaviour of reinforced concrete slabs.The main research work covers the following aspects:First,the basic conception of shear failure and punching shear failure is introduced as well as the calculating methods of the ultimate strength. And the comparative study is made between punching shear and shear failure from failure mode and failure mechanism.Second,all kinds of influencing factors of punching shear capacity are summarized. Such as:strength and composition of concrete,longitudinal anti-bending reinforcement,geometric dimensions of slab-column connections,boundary constraints and so on..According to a large amount of experimental data of slab-column failure,the formulas of shear capacity of reinforced concrete slabs are put forward,which are in good agreement with the test resukts,So, the suggested formulas can be used to predetermine the failure load of specimen in experiments as well as to support the calculation and design in practical projects.At last,the punching resistance behaviours of several slab-column connections are made by nonlinear finite element program ANSYS and the ultimate shear capacity of reinforced concrete slabs are acquired. Meanwhile, the crack mode,crack position and its developing condition.are analysed which coincide with the experiment.Therefore,it is feasible to simulate the punching shear performance of RC slabs with finite element analysis,and the simulated results can be used to direct the engineering practice.