ABSTRACT
Much of the discussion presented in previous chapters is focused on application of simple calculation approaches for tracing the fire response of structural members. These simple calculation techniques, though one step above the prescriptive based approaches, may not provide realistic fire response of structural system since a number of factors cannot be accounted for in simplified analysis. In lieu of these simple calculation methods, advanced calculation models can come handy for predicting the realistic fire response of structural response. These advanced calculation models are generally based on finite element techniques and can account for geometric and material nonlinearity, in addition to various high temperature effects, such as creep and transient strains, and restraint effects. The accuracy of the predictions is often dependent on the level of the complexity of the model adopted for the analysis, discretization utilized in the analysis, and on the accuracy of the input (material) data. In addition, the application of these advanced calculation models requires significant expertise, time and computational effort. As discussed in Chapter 2, advanced calculated models could be applied to a single
member, an assembly, or the entire building frame. The US codes do not specifically provide requirements or guidance on the use advanced calculated models. No specific guidelines are provided in North American codes such as IBC andNBCC, on the analysis procedure, or high temperature properties material models or design fires. However, the recent edition of AISC design manual (AISC 2005) describes the requirement for advanced methods of structural analysis for performance-based fire resistant design. It also recommends the use of Eurocode material properties for carrying out advanced analysis. Thus it is possible in North America to get regulatory approvals by undertake fire resistance analysis using the advanced calculation models. Eurocodes are more pro-active in facilitating the use of advanced calculation models
for fire resistance design and analysis. These codes provide detailed procedure to be used for analysis, constitutive models for high temperature material properties, as well as various parametric (design) fire curves. The details of these provisions are discussed in this Chapter.
