Experimental study on eccentric compression performance of high-strength concrete columns with HRB600 steel bars

In order to investigate the eccentric compressive behavior of high-strength concrete columns with HRB600 steel bars to promote their engineering application, nine high-strength concrete columns with cross-section dimensions of 600 mm×600 mm were tested under monotonic compression; the strength grades of concrete in the columns were C60-C100. HRB600 steel bars were used as longitudinal bars of seven of the nine columns, while HRB400 steel bars were used for the other two columns. The influence of design parameters such as the strength of steel bars, concrete strength, volume ratio of stirrups and load eccentricity on the eccentric compressive behavior of high-strength concrete columns was discussed. The results show that the failure characteristics, deflection curve and cross-sectional strain distributions of high-strength concrete columns with HRB600 steel bars are basically the same as those of high-strength concrete column with HRB400 steel bars. Under the large eccentric compression condition, the compressive bearing capacity of high-strength concrete columns with HRB600 steel bars is 8.55% higher than that of HRB400 steel reinforced concrete columns, and the load decreases gradually after the peak. With the increase of concrete strength grade, volume ratio of stirrups and stirrup strength grade, the compressive bearing capacity of high-strength concrete columns with HRB600 steel bars increases. It is reliable to use the relevant formulae in the current concrete structure design codes to calculate the compression-bending capacity, the average crack spacing and the maximum crack width of high-strength concrete columns with HRB600 steel bars. © 2019, Editorial Office of Journal of Building Structures. All right reserved.