Experimental Study And Nonlinear Finite Element Analysis On Seismic Behavior Of Z-shaped Reinforced Concrete Columns Subjected To Biaxial Shearing

In recent years, reinforced concrete structures with special-shaped columns have gained close attention and more actual applications due to its advantages in many aspects, such as it can effectively increase the utilization of space because of its flexibility in furniture arrangement, and it can reduce the structure load value based on its reduction for the structure’s overall weight. It can also reduce the consumption of engineering materials to some extent. In addition, compared to rectangular columns, special-shaped columns have certain advantages in building function. Although the “Technical Specification for Special-shaped Columns Concrete Structure” draft has turned up Z-shaped columns, the researches for Z-shaped columns’ performance are relatively few, in terms of Z-shaped columns’ performance subjected to biaxial shearing; only a few studies can be founded. Therefore, it is great necessary to do a detailed analysis for Z-shaped columns’ shearing performance subjected to biaxial shearing.In the section of experimental study of this paper, a total of four groups for Z-shaped columns analysis to the seismic performance were tested. Differences between the groups of specimens were mainly manifested in the loading angles. Both uniaxial shearing and biaxial shearing can be reflected through applying load in different angles. Through the observation and analysis of test results, several conclusion can be obtained. Such as, the failure patterns of Z-shaped columns under different loading angles are different from one another. The failure patterns include shear-bending failure, bending failure, shear-bond failure and shear compression failure. Different loading angles can also deeply influence loading bearing capacity, ductility and energy dissipation capacity for Z-shaped columns.In the section of nonlinear finite element analysis of this paper, first of all, it introduced the building of the model and the selection of the corresponding parameters in detail, then it conducted a comparative analysis between the experimental results and the nonlinear finite element analysis results. On the basis of this, it made a thorough inquiry about the feasibility of using the method of nonlinear finite element to analyze the shearing performance subjected to biaxial shearing for Z-shaped columns. In addition, it made an assay of the differences between them as well as the possible causes of these differences. Then on the basis of the test results it researched the influences for the Z-shaped columns’ shearing behavior subjected to biaxial shearing in the case of some different factors. These factors include loading angles, axial compression ratio, stirrup reinforcement ratio and ratio of section height. In terms of the influences of the different factors for the Z-shaped columns’ biaxial shearing seismic behavior, ratio of section height has a significant impact for the Z-shaped columns’ biaxial shearing seismic behavior. Loading angles and axial compression ratio can also influence the biaxial shearing behavior for Z-shaped columns to some extent. In contrast, stirrup reinforcement ratio has a relatively small impact to the biaxial shearing behavior. Compared to the results from the experiments, the nonlinear finite element analysis results has enough safety margin, so it has a certain sense of reference value for related structure designer.