Performance-Based Fire-Resistant Design Method for Long-span Steel Structure
|School||Shanghai Jiaotong University|
|Keywords||long-span building fire performance-based fire-resistant design fire scenarios design fire temperature field single layer spherical reticulated shell nonlinear analysis|
Long-span buildings are widely used because of their vast internal space, magnificent and beautiful architectural configuration. But the structure of long-span buildings is complicated with heavy fire load, and fire in the buildings spreads fast and is difficult to be put out. Also, the fire-resistance property of steel is poor. These reasons are prone to cause severe losses to human lives and assets. At present, the recipe-like fire-resistant design method based on the modern codes is mainly used in fire-resistant research of structure, but it has biggish limitation in practical structure fire-resistant design because it’s short of scientific nature, effectiveness and economical efficiency. Performance-based fire-resistant design method combines targets of fire safety, fire damage and design, and is appropriate for the buildings which exceed the request of modern codes. Therefore, it is of vital importance in theory and engineering practice to further conduct research of performance-based fire-resistant design method for long-span steel structure.With combining theoretical analysis and numerical simulation, performance-based fire-resistant design method for long-span steel structure is discussed systematically in this paper. The main research work covered in this paper includes the followings:(1) Research of large-space buildings’fire scenarios design methods. With introducing event tree model of fire scenario based on probability and characteristics of large-space building fire, design method of large-space buildings’fire scenarios is summarized. Fire scenarios of actual project case are designed by FDS.(2) Analysis of large-space buildings’fire temperature field. With the method based on field model, various kinds of influencing factors which affect large-space buildings’fire temperature field are analyzed by FDS. Then temperature of steel structural members is calculated based on the change law.(3) Parameters analysis of reticulated shell structure’s stability bearing capacity in fire. A nonlinear analysis of single layer spherical reticulated shell structure is carried out by ANSYS. The influencing parameters of structure’s stability bearing capacity are discussed. The change law of bearing capacity is summarized.(4) Parameters analysis of reticulated shell structure’s critical temperature and fire endurance in fire. Through following and analyzing the failure path of structural members with the structural members’elastic-plastic failure criterion, the change law of critical temperature and fire endurance is confirmed. Influencing factors of fire-resistant property are summarized.