Design of Tubular Steel Sections. Training and Education for the Implementation of Eurocode 3

Both steel and concrete suffer a progressive reduction in both strength and stiffness as their temperature increases in fire conditions. Eurocode 3 and Eurocode 4 provide material models for both materials over an extensive range of temperatures;
Fire resistance of structural elements is quoted as the time at which they cannot maintain their load bearing capacity;
It is possible to assess the severity of a natural fire for a particular steel element as a time-equivalent between the peak temperature in the steel element and the same temperature in the element submitted to the ISO834 standard curve;
The behaviour of separate elements is very different from that of a complete building frame, but the only practical way of assessing whole-structure behaviour is to use advanced calculation models;
Traditional fire protection of steelwork is by covering it with insulating material during construction. However it may be possible under Eurocode 3 to use a combination of passive and active strategies to ensure fire resistance;
Eurocode 3 calculation of fire resistance takes account of the loading level on the element, with values of the safety factors lower than those used at room temperatures;
Fire resistance may be calculated in terms of time, as a load-bearing resistance at a certain time, or as a critical element temperature appropriate to the load level and required time of exposure;
Critical temperature is calculated from a single equation in terms of the load level in fire for members of Classes 1, 2 or 3 sections if there is no instability phenomena involved. Class 4 sections are universally assumed to have a critical temperature of 350°C, but higher critical temperatures can be obtained by calculation;
Eurocode 3 provides simple calculations for the load resistance in fire of all types of elements. In cases where the strength is controlled by buckling, a buckling curve that is particular for the fire situation has to be used. The slenderness of the element is temperature dependent;
It is possible to calculate the temperature growth of protected or unprotected members in small time increments, in a way which can easily be implemented on a spreadsheet.