Mechanical Property Analysis on Concrete Short Columns with Strengthened Style Hoop
|School||Shandong University of Science and Technology|
|Keywords||S-Clip stirrup anti-seismic performance axial load test load-displacement curve load-strain curve ductility nonlinear analysis|
Based on the study of S-Clip reinforcing steel construction method, theoretical analysis on S-Clip reinforcement is presented in this paper. The constraint of reinforcement on the corner concrete is studied and it overcomes the corner defects. In the condition of guaranteeing capacity of reinforced concrete short columns, the deformability of short columns and ends of columns can be improved by reinforcement strengthening, and it provides a reference for the strengthening methods of short columns in ground floors and ends of common reinforced concrete columns of high-rise buildings. It is an effective method of reinforcement construction measure to improve columns’ anti-seismic performance.According to the differences of concrete grade, cross-section of stirrup and tensile ratio of reinforcement,30 reinforced concrete short column specimens were made to determine the effectivity of this new type of reinforcement. The process of compression failure and crack propagation of short columns can be seen directly through axial compression test on 30 specimens. In addition, load-displacement curves of short columns and load-strain curves of stirrups and longitudinal bars can also be obtained by analyzing data collected. Compared with well shaped compound stirrup, big S-Clip reinforcing steel and combination of compound stirrup and S-Clip reinforcing steel fixed in columns, the seismic behavior of those different short columns with different reinforcements were analyzed. Results show that corner longitudinal bars are constrained by this new reinforcement more effectively and it provides effective support for corner longitudinal bars. In the same time, this new type of reinforcement makes corner concrete in three-dimensional stress state, improves constraint on transverse deformation of concrete, and delays the crack propagation. The specimens behave in good ductility.In addition, we use the finite element software ANSYS to simulate one group of reinforced concrete short columns. By means of static nonlinear analysis, we can get the ultimate bearing capacity and observe the stress distribution of longitudinal bar, stirrup and concrete in different stress stages quantitatively. A complete load-displacement curve is obtained and compared to the one obtained from the experiment, and they conforms to each other well. The reliability of the experiment results is also proved and a new reference is provided to the effectiveness research and engineering application of reinforcement completely.From both experimental study and theoretical analysis, it proves that this new constraint reinforcement method can effectively improve the ductility of short columns.