Finite element analysis of eccentrically compressed performance of reinforced concrete columns after fire
Finite element(FE)analysis models were established for the temperature filed and eccentrically compressed performance of rein-forced concrete columns after fire exposure.The failure mode,load-deformation curve,bearing capacity calculated by FE method were in good agreement with the experimental results.An analysis was conducted on temperature changes and mechanical characteristics of circular and square eccentrically loaded columns.The results indicate that the temperature of the square section at the same distance from the outer surface is lower than that of the circular section.Under the influence of high temperature and stress,the maximum compressive stress and tensile stress of concrete in the eccentrically loaded column do not occur at the outermost edge of the section,but near the middle of the left and right halves.As the deflection increases,the position of the maximum compressive stress shifts towards the tensile side.When the fire exposure time is less than 90 min,the bearing capacity and stiffness of reinforced concrete columns decrease rapidly with increasing fire ex-posure time,and then decrease gently.The residual stiffness coefficient after fire is smaller than the residual bearing capacity coeffi-cient.After a fire exposure of 90 min,the residual bearing capacity and stiffness coefficients of reinforced concrete columns are about 0.45 and 0.37 respectively.
Reinforced concrete columnsAfter fireFinite element analysisTemperature fieldBearing capacity
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