Heat transfer analysis of the composite slab in the Cardington frame fire tests

The structural modelling of the Cardington Frame fire tests as part of the Department of Environment, Transport and Regions funded Partners in Technol ogy project has highlighted the importance of the temperature evolution bot h temporally and spatially in determining the structural response. Restrain ed thermal expansion/contraction and thermal bowing are the main driving fo rce behind almost all the structural phenomena witnessed in the tests. The four British Steel fire tests carried out on the 8-storey composite steel a nd concrete building at Cardington have provided a wealth of information ab out the temperatures in the fire atmosphere and the protected and unprotect ed steel. Unfortunately, there is considerably less information on the temp eratures attained in the concrete slab. In Tests 1-3, the temperatures thro ugh the depth of the slab have been recorded only at a few points and in te rms of the structural modelling this has been just about adequate. There we re no temperatures recorded in the slab in Test 4 (Office demonstration tes t). The finite element, adaptive heat transfer program HADAPT has been used to model the heat transfer to the composite steel and concrete slab. HADAP T is a 2D adaptive heat transfer code capable of carrying out a nonlinear, transient, thermal analysis. The code models moisture evaporation from the pores of the concrete by assuming a phase change in the region of 100 degre esC. The measured concrete temperatures in Tests 1-3 have been used to cali brate the model which has then been used to predict the slab temperatures i n Test 4. (C) 2001 Elsevier Science Ltd. All rights reserved.