STUDY ON THE EFFECT OF THERMAL CONTACT RESISTANCE AND COUPLED HEAT AND MOISTURE ON TEMPERATURE FIELD OF CFST COLUMNS

To predict the temperature field of concrete filled steel tubular (CFST) columns more accurately, the one-dimensional heat and mass transfer model of core concrete and the heat transfer model of CFST columns under fire conditions are established. The temperature field of core concrete is analyzed by using COMSOL, and then the effect of thermal contact resistance on the temperature field of CFST columns is investigated. The result indicates that: 1) considering thermal contact resistance and water vapor, the temperature developing inside CFST columns is predicted accurately; 2) compared with the heat conductive model, the heat and mass transfer model of concrete proposed in this paper generates more accurate prediction of the temperature field; 3) considering the thermal contact resistance, the calculated temperature of the columns is lower and the calculation error is larger near the surface of core concrete.