BACK-ANALYSIS OF THERMAL PARAMETERS FOR CONCRETE BASED ON TWO-DIMENSIONAL TRANSIENT HEAT TRANSFER AND FIELD MEASURING

摘要

With die development of performance-based design, some concrete structures should consider the temperature effects. However, thermal parameters obviously influence the temperature field as well as the thermal effect of concrete structures. Based on two-dimensional transient heat transfer and the field measuring, this paper presents a new method to determine the thermal parameters by back-analysis other than lab testing or literature overview. The back-analysis equation of thermal conductivity is derived based on the finite difference method and two-dimensional transient equation of heat conduction. Assuming that the temperature distribution near the concrete surface is the quadratic function of the coordinates, the backanalysis equations of heat transfer coefficient and absorption coefficient of solar radiation are deduced based on the thermal boundary conditions. Finally, the back-analysis of above thermal parameters of a concrete box girder is undertaken with the fieldmeasured temperature, meteorological data and the back-analysis equations.