Nonlinear Finite Element Analysis Of Shear Strength And Punching Strength Of Reinforced Concrete Structure

Since 1899, the shear problem of reinforced concrete members has been one of the classic problems of the basic theory of reinforced concrete structures. Although scholars from different countries have made extensive study on the problem, further study of shear failure mechanism is needed as the complexity of this problem. The members without shear reinforcement whose shear mechanism has been greatly simplified can serve as the basis of shear study of members with shear reinforcement. Therefore, with the further study on the basic theory of reinforced concrete structures and the development of computer simulation technology, it is necessary to carry out further study on shear problem of reinforced concrete members without shear reinforcement.This thesis studies the shear performance of reinforced concrete beams without shear reinforcement and the punching performance of reinforced concrete slab-column connections through nonlinear finite element simulation done by ATENA. The main work and achievements of this thesis are as follows:(1)Reasonable stress-strain laws of reinforcement, constitutive model of concrete, reinforcement bond model and related parameters of cracking simulation are selected to establish a nonlinear finite element analysis model. Bresler-Scordelis beam is numerically analyzed to verified the finite element model and prove the applicability of ATENA to simulate the behavior of brittle failure of concrete structures.(2)133 beams of Kani test are simulated with the verified model. The simulated results are in good agreement with those obtained in the test. Through further analysis of the simulation results of Kani beams, the shear capacity contribution of the arch and teeth action is studied respectively, and the interaction between the influencing factors of shear strength is analyzed. On this basis, a new empirical formula is proposed for the shear capacity calculation of beams without stirrups whose shear-span ratio is smaller than 2.5 based on a historical database.(3)10 reinforced concrete slab-column connections that have been tested by Hunan University and 8 slab-column connections without shear reinforcement that have been tested by German scholar Urban are simulated by ATENA. Through the analysis of the simulation results, the impact on punching strength of the cross section shape of columns(remaining the same calculated cross-section circumference u_m of slabs in punching failure) and the ratio of longitudinal reinforcement can be studied. Then a comparison of shear failure and punching failure is conducted.