Thermal gradients in uninsulated top floor

Thermal gradients in uninsulated top floor

Concrete top floors can be subjected to high temperature gradients due to sunshine. This applies to uninsulated floors systems and, in general, to all floors during the construction phase. The induced deformations, hampered by the connections to the rest of the structure, generate stresses in the region of the supports and require special constructive dispositions. These phenomena are not very well known by the prescribers, which leads today to neglect them or to adopt severe values of gradients.

The coupling of both thermal and mechanical studies has made possible to propose two analytical methods in order to determine the characteristic linear gradient to be used when dimensioning the floor. These two methods take into account the type of floor system (floor plate, hollow core slab…), its geometrical properties (alveolar shapes, thickness…), the presence or the absence of coating and its characteristics.