Study On Limit Value Of Axial Compression Ratio Of Steel Reinforced High Strength Concrete Column

With the development of modern construction, the height and the span of the building are on the increase, the traditional structures of reinforced concrete can not meet the requirements of the modern construction. The columns in the basement of the high rise building and the super tall building bear huge axial compression, if the high-strength reinforced concrete columns are still applied in the high-rise building, it will not only affect the columns'function, but will also shape short columns whose seismic behavior is poor, for limits of axial compression ratio will increase the size of columns section. It is well known trough lots of experiments that steel reinforced concrete columns can effectively reduce the axial compression ratio of columns concrete part and improve the seismic behavior of the columns because the steel skeletons in the columns can take part of the axial compression.As a result, reinforced high concrete columns, especially for the steel high-strength reinforced concrete columns, are applied widely in modern construction. Through repeatedly horizontal load tests, it is shown that axial compression ratio is an important target that affects seismic behavior of steel high-strength reinforced concrete columns,ductility and seismic behavior of columns will step down to a certain degree when testing axial compression ratio is high. Therefore, the axial compression ratio must be closely restricted in practical engineering in order to ensure seismic ductility of the columns reaching the required standard.Failure patterns, hysteretic curves, skeleton curves, ductile coefficients, energy dissipation and strength degeneration of steel reinforced high strength concrete columns are obtained by conducting tests of 3 specimens with concrete strength from 69.9MPa to 73.2MPa under low cyclic reversed loading and the influences of axial compression ratio on the seismic performance of steel reinforced high strength concrete columns are also analyzed. Finally the recommended limit value of axial compression ratio of steel reinforced concrete columns with concrete strength grades C65~C80 is determined based on the test results, which satisfies certain requirements of ductility.