High-Temperature Testing of Structural Steel and Modelling of Structures at Fire Temperatures.

摘要

This project consisted of material testing and modeling of structural steel at elevated temperatures and modeling steel-composite structures in fire conditions. The development of temperature increase in steel structures was studied and material models in fire conditions based on experimental results were used to determine the load-bearing capacity of structures in fire. In the first part of this report, the experimental test results for the mechanical properties of the studied steel grades S350GD+Z, S355 and S460M at fire temperatures are presented with a short description of the testing facilities. An extended test series was also carried out for cold-formed material taken from rectangular hollow sections and test results are also given in this part of the report. The second part of this report discusses a procedure developed for the structural analysis of steel and steel-concrete composite frames exposed to a localized fire and the results of several validation studies conducted to illustrate the procedure. The models were developed using the general-purpose finite element code ABAQUS. Another possibility is to use two codes, i.e. ANSYS and ABAQUS side by side. Specially written script files allow thermal loading to be applied either by importing the results of previously conducted three-dimensional heat transfer calculations or by generating thermal loads based on the analytically defined variations of temperature as functions of time and distance from the fire source along the beam. The third method is to input temperatures directly based on a valid distribution model. An overview of the design procedure is given in the introduction to this part and the methods used are discussed in detail in the bulk text. Also a sample ABAQUS input file is presented with detailed explanations.