Prestressing bed for precast concrete beams - has mould with fixed slotted end forms and pistons to assist striking

摘要

Plant for making precast 'T' section concrete beams or similar with tapered webs, uses a prestressing bed with one piece longitudinal moulds with the transverse end forms (22) welded to the walls. Vertical slots (23) opening out on the top edge locate the prestressing cables (24), used in conjunction with height-setting spacers and cover plates. The base of the mould can also be traversed by vertically displaced pistons which are flush fitting at repose, and which move into the mould to assist in striking. Piston displacement may be effected by a bar which supports several pistons and is itself displaced relative to the bed substructure, or may be effected by hydraulic jacks allocated individually to each piston.