Method And Application Of Performance-Based Fire-Resistant Design For High-rise Steel Structure

Modern high-rise buildings have the characteristics that the amount of fire hazards is large, evacuation time is long, fire spreads quickly and it is difficult to fight the fire. In the event of fire, there would be large economic losses and casualties. Therefore, the fire safety issue of high-rise buildings has always been a concern to people. In the fire, the strength and stiffness of steel will be greatly weakened, this may lead to component failure or even structure collapse. How to ensure the structural safety under fire is an important issue as design the structural fire protection of high-rise buildings.Current structural fire protection standard is a kind of prescriptive standard that based on the test results of structure components heated with standard temperature curve. This design approach is not rational and economic enough, and also unable to meet the growing demand for engineering practice.Performance-based fire-resistant design can solve some challengeable fire protection problem, if used in conventional buildings can preserve and protect the structural safety and reduce costs. Some domestic researcher proposed the concept of structural performance-based fire protection design and its framework, but further theoretical study and engineering design methods and development of related model require continuous improvement.Using fire engineering, thermal and structural engineering knowledge, this subject focused on researching the method and application of performance-based fire-resistant design of high-rise building. An engineering example is carried out at the end. The research content includes the followings:(1) Temperature in compartment fire. Compared with the existing test results, the validity of fire dynamics simulation software-FDS was verified. The relation of temperature in compartment fire with ventilation factor and heat release rate dose was analyzed using FDS. The results were compared with that calculated according domestic standard. It was found that the standard has some limitations and deficiencies.(2) Inner temperature distribution of steel members in real fire. Using finite element analysis tools to research the internal temperature distribution principle of unprotected and fire-protected steel components in thermal environment. Moreover, a program is developed with VB programming language to analyze the two-dimensional transient heat conduction of unprotected steel component.(3) Response of high-rise steel structure subjected to different fire scenarios. Structural characteristics of high-rise steel structure subjected to fire were analyzed and summarized. For different fire location, different fire spread ways, the structure deformation and internal forces were compared to find out a more dangerous fire scenario. Some suggests were proposed for the fire protection of steel structure and determination of fire scenarios in performance-based fire-resistant design.(4) The application of performance-based fire-resistant design method. Based on the research of performance-based fire-resistant design method, two structural fire protection programs were evaluated and compared using numerical simulation tools.