A proposed semi-prefabricated prestressed composite slab

This paper presents a semi-prefabricated prestressed composite slab, including experimental testing and appropriate numerical simulation tools, together with design guidelines and a parametric study of the main variables. The system was applied for the first time in Spain during the construction of the University of Lleida library covering 12 × 12 m spans with only 300 mm (L/40) total depth. This system considerably reduces the in situ work compared with other methods, allowing for large spans and two-way action. It is made up of three elements: (a) semi-prefabricated prestressed composite flat beams; (b) precast prestressed planks (namely preslabs); and (c) in situ reinforcement (transversal and negative) and topping concrete. Characterisation of element (a) using destructive experimental testing, as well as simple analytical and more precise numerical tools, using a layer model that includes constitutive equations for each material is included. A global analysis can be performed using a mixed finite-element formulation including orthotropy. This last effect is important in this system, due to the different positions of the longitudinal and transversal reinforcement.