GRAPHICAL METHOD FOR DESIGN OF STEEL STRUCTURES IN FIRE

摘要

The design of steel structures in fire is always a daunting task because of the complexity involved in carrying out such process. The whole process can be divided mainly into three parts: (1) Establishing the temperature-time curve for the fire which may include standard fire and natural fires; (2) Establishing the temperature-time curves for the steel members; this process involves heat transfer calculations based on analytical solution; (3) Checking the strength requirements of the steel members on the basis of the terrtpe'ratures attained. In essence, the design process involves three parameters: time, temperature and strength, all of which have to be assessed individually in order to satisfy the fire resistance requirements as stipulated in most building codes. In this paper, a method is proposed to link the three parameters together so that the design process can be carried out efficiently. The three parameters are expressed on a design chart from which design information, such as the required steel section properties, temperatures attained and the time required, for all the members in a steel structure can be extracted. The forces in the members are obtained from simple elastic theory based on a previously published method for steel structures in fire. An example is given to demonstrate the use of this method.