Multi-Storey Steel-Framed Buildings under Natural Fire Conditions: Fid-Bau Portal

Multi-Storey Steel-Framed Buildings under Natural Fire Conditions

Both, C. / Fellinger, J. H. H. / Berg, G. Van Den / Twilt, L.

During the last decade, numerical models are being used more and more to analyse the behaviour of structures under fire action. In view of the limited dimensions of the test furnaces, the validation of these numerical models is mainly based on fire tests on single structural components. It is common practice, at least in Europe, to exclude structural restraint in fire tests. Finally, the fire is schematised as the socalled "standard fire", to which all isolated structural elements are considered to be exposed to. The reason is that structural restraint is hard to accomplish and differs from case to case. In real structures, there will often be -to some extent- structural restraint. As a consequence, the single-element standard fire approach is conservative. The ECSC co-sponsored project "The behaviour of a multi-storey steel-framed building subject to fire", offers unique possibilities to validate numerical models on the basis of realistic full scale fire tests on complete structural systems, including restraint effects. These "natural" fire tests are carried out at the Large Building Test Facility at Cardington. The potential of the FEM package DIANA to describe the thermal and mechanical response of fire exposed structural elements and systems, is illustrated on the basis of numerical analyses of natural fire tests on composite steel/concrete structural systems. It is demonstrated that structural restraint may significantly increase the fire resistance. Furthermore, it is demonstrated that significant savings can be made on passive fire protection measures. Finally the outline and the preliminary results of a parametric study are presented.