A Simulation And Test Of Nonlinear Deformation Decomposition In Reinforced Concrete Columns

As far as the devastating earthquake is concerned all over the world in recent years, there are a large number of reinforced concrete columns having been destroyed, and most of them are in the top position. As a significant component in architectural construction, the reinforced concrete column should bear both the vertical load and horizontal load. Moreover, the destruction of some columns would have an impact on a whole structure. Therefore, the study on the non-linear deformation ability of reinforced concrete columns under the seismic waves is of great meaning both at home and abroad.This thesis aims to draw a conclusion of the previous study:①There are four reinforced concrete columns having been studied by cyclic lateral loading test (the span-to-depth ratio of the two is 3, and the other is 2.1), after considering the impact of axial compression ratio and span-to-depth ratio on the non-linear deformation ability of the sample, column end hinge flexure deformation, shearing deformation and bond-slip have been measured at the same time. The hysteresis relationships between the four top load and top displacement of the sample, the top load and column end hinge flexure rotation, the top load and the fixed end rotation caused by bond-slip, and the relationship between the top load and shear angle are given out after the test.②This dissertation measures the flexural deformation in the columns plastic hinge, shear deformation and slippage of longitudinal reinforcement, arriving at three parts deformation ratios and their contributions to the lateral displacement of column capital. Among them, the flexural deformation has the greatest contributions to it, which is basically above 50%. The slippage of longitudinal reinforcement comes next with a percentage between 20 and 40. The last one is shear deformation, which has the least contributions to the lateral displacement of column capital. The ratio is around 10%, with regard to the columns of the span–to-depth ratio 3 while 10%-30% as to that of the span–to-depth ratio 2.1.③According to the modeling bond-slip method proposed by Gaowensheng, this thesis aims to ascertain the value of the modeling bond-slip parameter of the four reinforced concrete columns. Then, through the simulation test of the four reinforced concrete columns (with the consideration of bond-slip) under OpenSees, we can find that the error of the value of simulation to trial value is around 10%, which can better demonstrate the bearing capacity of the sample. The error of the column end hinge flexure rotation and trial value is below 30% while the error of the fixed end rotation caused by bond-slip is beyond 30%.④In order to study the impact of the shearing effect, a simulation test of two columns (λ= 2.1) under OpenSees has been made accordingly. The results show that the bearing ability of samples with considering of the shearing effect is under declining, and the results of the columns with a 0.1span-to-depth ratio is under 10% comparative error while the columns with 0.3 is around 15%.