FP McCann manufactures a range of reinforcing units suitable for sinking by the caisson method. Caisson shaft units can be supplied with diameters of 2100mm up to 4000mm.
Caissons are manufactured within the scope of the ISO9001 accredited Quality Management System and in accordance with BS EN 1917 and BS5911-3, where appropriate^. However, 3600mm and 4000mm diameters remain operative within the scope of the ISO9001 accredited Quality Management System.
Open caisson-sinking techniques permit a shaft structure to be progressively sunk, either under its own weight or with the aid of caisson jacks. This is done in a controlled manner from the surface to a predetermined depth. Caisson shafts are constructed using a metal cutter ring and a base section with rings being added on top as excavation proceeds. The technique is suited to shaft construction through weak soils, high-plasticity clays, silts, sands and gravels, particularly below the water table.
^ Caisson manholes cannot be CE marked as their diameters are not covered by the scope of the harmonised European Standard BS EN 1917. However, 2100mm – 3000mm manholes are kite-marked against the scope of the complementary British Standard BS5911-3.