Experimental Study On Ductility Of Section Of Reinforced Concrete Column With 500MPa Rebar Under Eccentrically Loading

Nowadays 500 MPa high strength reinforcement has been specified as recommended rebar by “Code for design of concrete structures”(GB50010-2010)and “Steel for the reinforcement of concrete”(GB1499.2-2012),but in the practical engineering,500 MPa high strength rebars are not be popular used.So far,there are so much research of concrete component use 500 MPa reinforcement at home and abroad,but the formerly research major in the bearing capacity and seismic behavior of component,the research of ductility of concrete component under the monotonic load is not abundant,especially for the influence rule of ductility of parameters of 500 MPa reinforcement concrete under eccentric compression.In this paper,the experimentally ductility of 500 MPa grade reinforced concrete column under eccentric compression is experimentally studied.In the experiment,6 specimens were designed and loaded,the cross sectional dimensions of the specimens are 300mm×400mm,and the height is 1700 mm.The main parameters are longitudinal reinforcement ratio,eccentricity ratio and concrete strength grade.According to the test results,the characteristic of load-deflection,the characteristic of load-strain,lateral displacement,bending moment-curvature curve were analyzed.Based on the test result,the numerical models were established by using the cross analysis software XTRACT,and the accuracy of the model was verified.Based on the model,102 sections of 500 MPa reinforced concrete column under eccentric compression with different concrete strength,reinforcement ratio and eccentricity ratio were designed.The influence of different factors on the ductility of section was analyzed comprehensively.Finally,according to the analysis results,the simplified formula of the ductility of 500 MPa reinforced concrete section under eccentric compression was proposed.The analysis result show:1)The process of 500 MPa reinforced concrete column under eccentric compression is similar to that of ordinary reinforced concrete columns.The cross section corresponds to the flat section assumption,and the lateral deflection distribution corresponds to the sine half-wave curve;2)Section analysis software XTRACT can effectively simulate the force situation of 500 MPa reinforced concrete column under eccentric compression;3)The influence of longitudinal reinforcement ratio on the ductility of cross section curvature is large and the ductility decreases with the increase of the reinforcement ratio.In the design of the project,designer can control the maximum reinforcement ratio to control the cross-section ductility;4)The strength of concrete has some influence on the ductility of section,and the ductility increases with the increase of concrete strength;In the design of the project,designer can improve the strength of concrete to adjust the axial pressure ratio to improve the cross-section ductility;5)The eccentricity has a great effect on the ductility of section,and the ductility increase of the eccentricity;6)The simplified formula for the curvature ductility of section can be used as a recommended formula.