Experimental Research On Seismic Performance Of Rc Columns After Fire With Damages Caused By Marine Environment

In order to study the seismic performance of corroded reinforced concrete columns in marine environment after fire,4 concrete columns with the same size and reinforcement were designed and manufactured,and carried out the corrosion test and high temperature test on them.Specimens generated different width of corrosion expansion crack by electrochemical accelerated corrosion test,which was taken as the damage index to simulate the chloride corrosion of reinforced concrete columns.Then,fire test was carried out on the specimens with initial damage under axial restraint,and analyzed the temperature field of the section.Finally,made a research on the seismic performance of reinforced concrete columns after fire.In concrete column,the stirrup located outside will produce deeper corrosion than longitudinal reinforcement,stirrup corrosion will result in a reduction in restraint of longitudinal reinforcement and concrete core,so the research of steel corrosion on the seismic performance of concrete columns must be considerate after high temperature corrosion stirrups.In this paper,the seismic behavior of corroded reinforced concrete columns subjected to elevated temperature are investigated,and the seismic behavior of corroded reinforced concrete columns after fire is investigated.Specific research contents as follows:(1)The mechanical properties of corroded reinforcement and the mechanical properties of corroded concrete were summarized.The mechanical properties and mechanical properties of reinforced concrete were summarized;(2)Electrochemical accelerated corrosion test was used to simulate the erosion of chloride ions on reinforced concrete columns under marine environment,and 3 specimens were subjected to corrosion crack with different width.The experimental phenomena and results were analyzed;(3)The fire test of reinforced concrete columns with corroded stirrups was carried out.The experimental phenomena were analyzed and the experimental data was obtained.The influence of the corroded swelling cracks on the temperature field and axial deformation of the concrete columns after high temperature was obtained;(4)The seismic behavior of corroded reinforced concrete columns subjected to elevated temperature were investigated,made an observation and analysis of crack in the failure modes,studied the effect of stirrup corrosion performance of reinforced concrete columns after high temperature resistance,and put forward calculation model of reinforced concrete column shear capacity after high temperature;(5)After the seismic performance test,took the core of reinforced concrete column and measured the strength of concrete after fire;the specimens were worn out and cut off some stirrups,measured its rate of corrosion.