chapter  7
22 Pages

Global modelling of structures in re

As a result of the introduction of performance-based approaches to design, it is now possible for designers to treat re loading in the same manner as any other form of load. However, for this to happen it must be possible for designers to predict with con dence how a structure will respond to re. Considerable research effort has been dedicated in recent years to providing the knowledge needed for this, and much progress has been made. It turns out that structural behaviour in re in all but the simplest cases is much more complex than analyses based solely on loss of material strength due to heating, such as those based on the Standard Fire Test, can predict (e.g. Usmani et al. 2001). A nding is that analyzing structural elements, such as beams and columns, in isolation and with idealized supports (as is common at ambient temperature) in a re analysis is insuf cient if an understanding of the re resistance of entire structures is desired. For accurate results to be produced, either the behaviour of whole structures or the behaviour of large parts of structures with appropriate boundary conditions must be considered. As a result, in all but the most straightforward cases, numerical analyses are required to predict accurately the strength and behaviour of structures in re.