Experiment Research on the Inverse Presumption Method to Evaluate Peak Temperature for Post-fire Spatial Structure

The peak temperature is one of the most important factors to evaluate the structural damage. Due to the reduction in the tensile strength of the steel, the structural stress is redistributed and the bearing capacity is decreased at the elevated temperature.

This paper presents an inverse method to evaluate the peak temperature for the steel structures subjected to fire. An initial temperature field is assumed based on the post-fire structural residual displacement, and a temperature iteration function is developed to approach the peak temperature of the structure in fire by minimizing the difference between the measured and numerical results. An experimental study was conducted to investigate the structural behavior of a spatial structure subjected to fire. The temperature and displacement data were recorded.

Results show that the measured results have a good agreement with the predicted results, demonstrating that the proposed method in this paper is available for evaluate the peak temperature with a desirable accuracy. The inverse method of the temperature field can provide a theoretical basis for scientifically evaluating the residual displacements of the post-fire structure and formulating reliable repair and reinforcement schemes.