Precast Concrete Attenuation Tank for Duddeston Mill Road

This contract opportunity involves the design and supply of a precast concrete attenuation tank located at Duddeston Mill Road North in Birmingham. The tank will measure 31 meters in length, 8.35 meters in width, and 1.70 meters in height, featuring a two-span box structure. It will include at least two access points near the inlet and outlet, with openings measuring 750x750mm. The entire structure will be made of precast concrete elements that are designed to be integral twin-cell box structures without joints, connected by a concrete spigot and socket joint. Each precast element is expected to have a minimum design working life of 120 years, with specific lifespans for waterproofing (30 years) and sealants (20 years to first maintenance). The scope includes design, supply, and delivery only, with future waterproofing details to be agreed upon during the design phase. Lifting points must be included in the design, and units are anticipated to arrive with a bituminous waterproofing system applied. Suppliers should also include any assumptions and exclusions in their proposals.