Numerical simulation of thermal and structtural response of composite steel/concrete slabs to fire

Existing calculation rules for the assessment ofthe fire resistance of composite steel/concrete slabs are based on fairly limited and dated experimentally evidence [ECCS 1983: Twilt et al, 1991]. At the time when the rules were developed, numerical models were not suitable to perform parameter studies in order to obtain -besides experimental evidence- additional information and insight. As a consequence, gross simplifications and global assumptions had to made, which in genera! lead to conservative calculation rules [Twilt, 1991]. In order to address this problem and obtain more fundamental insight into the behaviour of composite steel/concrete structures, a joint research project was started, in wh ich France (CTICM), Luxembourg (ARBED) and the Netherlands (TNO and Delft University of Technology) took part. The project aimed at the development and improvement ofsimp Ie calculation rules for fire-exposed composite steel/concrete beams and slabs. The part on composite beams was carried out in France at CTICM. The part on composite slabs was carried out in the Netherlands at the TNO-Centre for Fire Research. ARBED Luxembourg provided genera! assistance in numerical work. The strategy followed in the research project was as follows. First, advanced numerical tools were developed, which were validated on the basis of a limited number of well equipped/instrumented full scale fire tests. With the numerical models, parameter studies were carried out. The results ofthe parameter study were used to set up new design rules, which should be easy to hand Ie, but at the same time sufficiently differentiated, in order to allow economie/ competitive dimensioning. In the next section, emphasis is on the numerical modelling ofthe full scale tire tests on composite steel/concrete slabs. In the next section, the main characteristics ofthe numerical models are indicated. In the third section, the potential ofthe models is described, on the basis of a comparison between numerical and experimental results. Finally, some typical results are given ofthe proposed new calculation rules, derived from extensive parameter studies with the numerical models.