Experimental investigation on axial compressive performance of high-strength concrete short columns reinforced by HRB635 longitudinal rebar and stirrups
In order to study the mechanical properties of high-strength reinforced concrete short columns constrained by high-strength stirrups under axial compression and the compatibility between the three materials,the axial compression tests of 11 high-strength reinforced concrete short columns constrained by high-strength stirrups of HRB635 were carried out,and the influences of the strength of concrete,longitudinal reinforcement strength,and the volume stirrup ratio on the axial compression performance of columns were investigated.The results show that the axial compression capacity and stiffness of columns mainly increase with the increase of the volume ratio of high-strength stirrups and the concrete strength.The high-strength stirrups do not yield at the peak load,so the stirrup strength has little impact on the axial compression capacity,and the stirrup strength does not need to be considered when calculating the axial compression capacity,but it significantly improves the ductility of the specimen.When HRB635 high-strength longitudinal bars work together with concrete below C60,the longitudinal bars do not yield at the peak load,making it difficult to fully utilize its strength.Therefore,HRB635 high-strength longitudinal bars should be used together with concrete above C60.In addition,the calculated axial compressive capacity of reinforced concrete columns constrained by high-strength stirrups using the formula in GB 50010-2010 and ACI 318-14 for reinforced concrete columns is too conservative.Collecting the existing relevant test data,the calculation formula for the axial compressive load capacity of reinforced concrete columns was modified,considering the hoop reinforcement and high-strength longitudinal reinforcement not yielding,and the calculation results are in good agreement with the experimental results.
short column of axial pressurehigh-strength hot rolled steel barhigh-strength concreteaxial compression performanceconfinement effectbearing capacity calculation