Comparative Analysis Of Reciprocating Load Tests Of Several Confined Concrete Columns

Regional confined concrete is a new concept based on confined concrete.For columns,they make use of steel skeleton that formed with longitudinal reinforcement and stirrups to strengthen its range within the constraints surrounding the effect,In the corners of the column section formed strong confinement region. Weak confinement region is connected between the strong constraint region.Strong confinement region and weak confinement region form an organic whole.Regional confined concrete columns with bars-channel steel and regional confined concrete columns with channel steel are two new cross-sectional forms based on regional confined concrete columns. The former is a form that channel steel take place of longitudinal steel in the corners of regional confined concrete column,using large channel flanges to better strengthen the binding effect.The latter one is a form that channel steel not only take place of longitudinal steel in the corners of regional confined concrete column,but also take place of longitudinal steel in the center. Channel steel has greater lateral stiffness and better concrete constraint effect compared with steel.They can effectively improve the seismic performance of the column.This paper analysis the hysteresis curves, skeleton curves, ductility and energy dissipation and stiffness degradation performance of specimens by cyclic loading test under 1.1, 1.3 and 1.6design axial compression ratio for these two new cross-sectional types of regional confined concrete columns.Besides,this paper discusses the seismic performance of section steel regional confined concrete and analysis all specimens by the ABAQUS finite element software on the trial.The result shows that these two new cross-sectional concrete still have a good seismic performance under high axial compression ratio.The seismic performance of regional confined concrete with bars-channel steel decreases with axial compression ratio increasing.The seismic performance of regional confined concrete with channel steel shows a trend from decline to fall with axial compression ratio increasing. Its optimum axial compression ratio is about 1.3.The two new type regional confined concrete columns can improve the ductility and energy dissipation capacity of concrete under high axial compression ratio. The ultimate strain and interlaminar displacement angle of them exceed the requirement 0f technical specification for concrete structures of tall buildings.They can solve the problem of short column effectively and has broad application prospects.