Experimental Study And Finite Element Analysis Of Mechanical Behavior Of Concrete Compression Columns With HRB600 Steel Bars

With the progress of economic construction and the acceleration of urbanization,buildings will inevitably develop towards high-rise and heavy loads,and correspondingly,higher requirements are imposed on reinforced concrete materials.HRB600 rebar is a high-strength concrete structure rebar introduced in China after HRB400 and HRB500 series rebars.It has the advantages of economy and efficiency.However,the strength of the rebar used in our country is relatively low,and the research on HRB600 high-strength rebar is relatively lacking.In order to improve the mechanical performance research system of HRB600 reinforced concrete members,promote the engineering application of high-strength steel bars,and alleviate the problems of high pollution and high consumption in the construction industry,this article focuses on HRB600 reinforced concrete bias columns The mechanical properties of stub columns with axial compression were studied.An eccentric compression test was performed on 12 HRB600 reinforced concrete columns,and how the two variables,eccentricity and reinforcement ratio,affected the failure shape,deflection and crack development of the specimens were analyzed.The cracks of the biased column were calculated according to the Chinese,American and European codes,and suggestions for improvement of the Chinese codes were compared and compared with the American and European codes.The results show that the failure process and crack development of HRB600 reinforced concrete biased columns are closer to those of ordinary reinforced concrete biased test specimens.The smaller the eccentricity of the specimen is,the larger the bearing capacity is,and the bearing capacity of the large-biased specimen increases with the reinforcement ratio.The higher the reinforcement ratio of the specimen,the smaller the deflection in the column,and the larger the eccentricity,the greater the deflection.Increasing the reinforcement ratio will make the cracks of the specimen become fine and dense.The larger the eccentricity,the larger the crack width.The existing domestic code is more applicable to the calculation of the crack spacing of HRB600 reinforced concrete biased columns.It is recommended to reduce the component stress characteristic coefficient from 1.9 to 1.7 when calculating the crack width.The calculation of the cracks of HRB600 reinforced biased columns according to the US and European standards basically meets the requirements of the code.US requirements are more relaxed.Axial compression tests were performed on 6 HRB600 short reinforced concrete columns and 2 plain concrete short columns to analyze the influence of factors such as concrete strength and reinforcement ratio on the mechanical properties of the test specimens.Calculate the bearing capacity of the axial column using the Chinese and American codes,and analyze the advantages and disadvantages of the two codes.The finite element simulation software ABAQUS was used to numerically simulate the concrete axial compression column,and the effects of factors such as the diameter of longitudinal reinforcement,the strength of the longitudinal reinforcement,and the spacing of the stirrups on the mechanical properties of the axial compression column specimens were expanded.The results show that the peak displacement of the short column under axial compression decreases with the increase of concrete strength,and increases with the increase of the strength of the reinforcing bar and the ratio of the hoop.Compared with the American code,the bearing capacity of the axial pressure column calculated according to domestic codes is superior and has sufficient safety reserves.The ABAQUS finite element simulation curve can capture the displacement of each characteristic point of the test curve,and the model has high accuracy and reliability.The peak load of an axially compressed column increases with the increase of the diameter of the longitudinal ribs and the strength of the longitudinal ribs,and decreases with the increase of the spacing between the stirrups in the middle of the column.The peak displacement is less affected by the longitudinal reinforcement ratio and longitudinal strength,but it increases with the spacing of the stirrups.