Experimental Study On Mechanical Performance Of HRB600 RC Eccentrically Loaded Columns

HRB600 steel bar is a kind of high-strength steel with high strength and good ductility.Currently,it has been included in “Steel for Reinforced Concrete Part 2: Hot-rolled ribbed bar”(GB 1499.2),but it is not included in the “Code for Design of Concrete Structure”(GB50010-2010)due to the lack of basic experimental research on HRB600 reinforced concrete beams,plates and columns.The column is an important force-bearing member in concrete structure,and the eccentric compression member is the most widely used compression member in engineering.Therefore,the experimental study on HRB600 reinforced concrete eccentric compression column is conducted in this paper,which also provides the theoretical basis and experimental basis for the application of HRB600 reinforcement.In this paper,9 HRB600 reinforced concrete eccentrically loaded columns were subjected to unidirectional loading test to observe the effect of reinforcement ratio and eccentricity on the mechanical properties of components and failure forms of the specimens.The load-deflection,load-steel strain,load-concrete strain,moment-curvature curves of the specimens were compared and analyzed,and the bearing capacity formula of HRB600 reinforced concrete column was studied.The results show that the damage process and characteristics of HRB600 reinforced concrete bias column are same as the ordinary reinforced concrete bias column.When large eccentric pressure is applied,there are many transverse cracks,tensile steel bar yield,compression concrete of compressive side and specimen damage.When near eccentric pressure is applied,the lateral crack is less,the concrete of compression side is crushed and the damage is sudden.The analysis of load-strain curve and moment-curvature show that the HRB600 reinforcement has good performance in the column and the strength can be used sufficiently.The bearing-capacity calculation formula of HRB600 reinforced concrete column can still follow the calculation method in “Code for Design of Concrete Structure”(GB50010-2010),and it has a good safety reserve.In this paper,it is suggested to take the design value of tensile strength of HRB600 steel bar as 520 MPa and compressive strength as 435 MPa.Based on the HRB600 reinforced concrete eccentrically loaded column stress performance test completed in this paper,the experimental specimen was analyzed by ABAQUS.The damage form of concrete,ultimate bearing capacity,load-steel strain curve,load-concrete compressive strain curve and moment-curvature obtained by simulation were basically consistent with the test results.