ABSTRACT
The access floors represent a fast, economic and flexible way to cover great surfaces for offices, commercial activity and warehouses. They are built with modular square plates of reduced size (usually 50 × 50 and 60 × 60 cm in plan), made with structural concrete. Their weight and thickness are carefully calibrated through stringent in-factory quality controls to reduce the cost of transport and setting in place. Nevertheless the attempt of reducing the self-weight makes these elements more sensitive to static and dynamic loads. Moreover during their service lives the plates are exposed to moving loads that induce the risk of fatigue failure. In fact, the duration of fatigue life represents one of the major concerns in the design of the plates. Some standards, such as the Recommended test procedures for access floors issued in the U.S. by C.I.S.C.A. (Ceiling & Interior System Construction Association) (CISCA 2004), point out the minimum acceptable resistance to moving loads of these products and specify the way to verify this resistance. While the static load bearing capacity can be easily predicted, assessed and even improved, the fatigue resistance evaluation needs more accurate and complicate considerations requiring a design phase that may include both numerical simulations and experimental verifications.
