Fire Resistant Performance Research About Reinforced Concrete Columns

Due to the reciprocities between steel and concrete, reinforced concrete columns has not only predominant mechanical performance, but also good fire resistance. This paper carried out a set of academic analysis to know mechanics of reinforced concrete columns subjected to fire. The main contents as follow:(1) Summed up research productions on thermal properties and mechanics of steel and concrete under high temperature inside and outside of country. Based on it, the thermal properties and heat mechanics of steel and concrete that composed reinforced concrete columns are confirmed. And stress-strain relation models of steel and concrete are established.(2) Finite element model for the calculation of the temperature field of reinforced concrete columns have been set up. A corresponding program is worked out. And a comparison between calculated results using this model and testing results has done, there is a good agreement; influence of parameters on failure load is analyzed. Conclusion as follows: sectional dimension and the fire exposure time are main parameters to affect temperature field. The influence of the number of heated face can be ignored.(3) Confirmed the theoretical model for calculating failure load of reinforced concrete columns. A corresponding program is worked out. The program is validated by testing results. There is a good agreement; influence of parameters on failure load is analyzed. Conclusion as follow: sectional dimension,concrete cover and concrete strength are main parameters to affect failure load. The influence of steel ratio and steel yield strength can be ignored.