Finite element analysis of 3D temperature fields in structures subjected to fire

White calculating structural response of a structure in fire environment it is necessary to know temperature distribution in members with good accuracy. Most researchers used the assumption that there is no temperature change along the axes of beams or columns and treated the histories of temperature distribution in a members subjected to fire as two-dimensional problem. Strictly speaking, the temperature distribution in some parts, such as beam-column joints, is three-dimensional. More recent studies suggest that the behavior of beam-column joints have significant effects on the behavior of structural response of a structure in fire. In short, it is important to treat the temperature distribution in these key parts as three-dimensional. A nonlinear finite element program called T3D was developed for predicting the three-dimensional temperature distribution histories of structures subjected to fires. The temperature-dependent thermal properties of structural materials and convective and radiative boundary conditions are considered. Comparisons between calculated and test data shown that program T3D is of high accuracy. Two examples are given.