12 ½” thick Hollow Core slabs are highly recommended for all detention vaults. Hollow Core slabs for detention vaults are generally untopped and the 12 ½” thick Hollow Core slab is designed with a thicker top flange to provide greater durability and increased “punch-through” shear capacity normally supplied by a cast-in-place, composite concrete topping.
The Hollow Core slab is manufactured in a standard 4’ width and 8”, 12”, and 12 ½” thicknesses using a continuous concrete extrusion process. Zero-slump, high-strength concrete with a 28-day strength in excess of 8,000 psi and ½” diameter, 270 ksi, low relaxation steel strands are used in the process.
Narrow-width slabs are available at additional cost by rip-cutting standard width slabs. Economical layout of the slabs utilizes as many of the standard 4’ wide units as possible with the remainder of the layout filled with non-standard width slabs or cast-in-place closure strips.