Experimental Study On Concrete Frame Columns With Central Reinforcement Under Cyclic Lateral Loading

It is an important conclusion comes from most investigation of earthquake damage and experiment researches that under the effect of earthquake, the collapse of building is always due to failure of reinforced concrete columns which can be prevented by improving the ductility of concrete frame columns. There are many engineering methods to improve the performance of columns, such as permitted axial compression ratio; control shear span ratio; enhance stirrups arrangement; concrete-filled steel tube and steel reinforced concrete. There is a new kind mode of reinforced concrete columns in this article, which is concrete frame column with central reinforcement.Through the experiment on one general concrete frame column and four concrete frame columns with central reinforcement under high axial compression ratio and cyclic lateral loading. This paper described the destructive process and characteristics of column; according to the P-â–³hysteretic curve; skeleton curve of specimen and the data from the test, it studied and calculated the displacement ductility ratio, strength and stiffness degradation ratio, viscous damping coefficients etc. for each specimen; the major factors affecting are also discussed. The test and analysis results show that under high axial compression ratio, area of cross section, volumetric tie ratio and longitudinal reinforcement ratio of core column all have different influences on both ductility and elastic-plastic deformation of concrete frame columns with central reinforcement, They are not only the mechanical capability of concrete frame columns with central reinforcement could improved effectively, but also an important measure to guarantee the seismic behavior by reasonable arrangement of the core column.In addition, this paper elaborated on the basis of the actual seismic design methods and kernel for the concrete frame columns, its research and discussion focused on the performance of seismic in ductility; strength; stiffness and energy-dissipation. It is provide the referenced gist for design and application of concrete frame columns with central reinforcement; it also will be laid the foundation for the theoretical study and project practice in the future.