This report presents detailed and reduced-order finite element modeling of heat transfer in composite floor slabs with profiled steel decking. The detailed modeling approach uses solid elements for the concrete slab and shell elements for the steel decking. The reduced-order modeling approach represents the thick and thin parts of a composite slab with alternating strips of layered shell elements. In the reduced-order modeling approach, a linear gradient in the density of concrete in the rib is used to represent the tapered profile of the rib. In order to more accurately account for the heat input through web of the steel decking in the reduced-order models, the specific heat of concrete in the rib is modified and a dummy material with low specific heat and high thermal conductivity is added in the thin part of the slab. The detailed modeling approach is validated against experimental results available in the literature, and the reduced-order modeling approach is calibrated against the detailed model results and validated against experimental data. A parametric study using the detailed modeling approach is carried out to investigate the influence of the thermal boundary conditions, thermal properties of materials, and slab geometry on the temperature distribution in the composite slab. The results show that the rib height of the decking and the width at the top of the rib are key factors governing the temperature distribution in the rib. In addition, a mesh-sensitivity analysis is performed to investigate the extent to which the mesh size could be increased while maintaining sufficient accuracy.
Technical Note (NIST TN) - 1958
heat transfer, composite slab, detailed model, reduced-order model.