Hollow core slabs, or plank, are precast prestressed concrete components typically used as structural floor or roof deck systems in single and multi-story buildings. To reduce weight and provide a more efficient product, the planks are cast with continuous voids that run the length of the panel. Prestressing the slabs creates an exceptionally strong structural component that can be used to span areas up to 45 feet in length.

At J. P. Carrara & Sons, Inc, we produce our Dynaspan hollow core plank on three 500’ long beds – a 4’-0” wide bed, an 8’-0” wide bed, and an 8’-3” wide bed which is the widest of its kind in New England. The use of 8’ wide plank significantly reduces the number of plank and thus the number of joints required in the structure resulting in time and cost savings for the owner. The wider plank can also accommodate larger mechanical openings than narrower systems without the need for steel support headers in most cases. The plank we produce has a smooth bottom surface which can be suitable for use as a finished ceiling, and our “carpet ready” plank can be finished with a smooth top surface ready for a direct flooring application.

Our 8’-0” production line produces 8” & 10” thick plank. Our 8’-3” line produces 6”, 8” & 10” thick plank and our 4’-0” line produces 8” & 12” thick plank. The required thickness of plank is dependent upon design loads and the desired length of span.

How It’s Done
We are often asked how we handle our large 8’ wide hollow core plank in the field. Typically, plank installers sling the plank at each end with cables to place the plank in the structure. They then have to leave the plank apart from the adjacent plank in order to remove the cables then bar the plank over tight to close the gap. This process is time consuming and increases the likelihood of chipping and spalling the bottom edges of the plank. J.P. Cararra & Sons utilizes vacuum lift devices to lift the plank and set them in their required location in the structure. These vacuum lifts are rated for up to 15 ton picks and can handle up to 8’ wide x 36’ long planks.