In summary
- A new housing development required an upgraded and expanded supply of potable water
- We were commissioned to design and build a new water tank to manage the increase in demand
- The project included demolishing the existing water reservoir
Project in numbers
8 million litres capacity of the new-build water tank
14k properties provided with long-term water security
The need
The construction of a new housing development in Southeast England led to the need for an upgraded and expanded domestic water supply. The existing water reservoir had been condemned and needed to be replaced.
We were approached by Cambridge Water to complete the demolition and construct a new-build water tank for 8 megalitres of potable water.
The solution
Working with a specialist design partner, we engineered a tank that would fit into the footprint of the previous tank but increase the amount of storage to account for the new demand.
The existing site dictated a footprint that was non optimal for water flows, however, a computational fluid dynamics (CFD) analysis was completed, and we implemented a best practice design to reduce dead spots and protect future water quality.
As the site footprint dictated a tank shape that was non-optimal for water flows, a computational fluid dynamics (CFD) analysis was completed to identify a ‘best practice’ design to reduce dead spots and protect water quality.
Our water engineers began by demolishing a condemned pre-stressed tank and excavating the site, removing much of the old pipework and capping other pipes for later reconnection.
Groundworks, including underdrains, were then installed. This was followed by concrete blinding and steel reinforcements. We laid a concrete base slab and constructed the walls over a series of 4 concrete pours. Overflow and outlet pipework was installed.
To minimise working at height, the top reinforcement cage was fabricated in sections on the ground before being craned into position. The roof was made from steel beams topped with reinforced pre-cast concrete slabs, lifted into place with a tower crane. Structural and lycast screed were laid on top of the new reservoir, and a waterproof liquid membrane applied.
Mechanical, electrical, instrumentation, control and automation (MEICA) elements were installed, including security alarms and access for service engineers.
The new-build water tank underwent a 7-day drop test, to check for potential leaks, before being drained for a final inspection. This was followed by a final clean and chlorination ready for handover.
The benefits
- The new tank has significantly increased storage capacity, utilising the existing site and removing the need to find further land on which to build. The outcome has provided long-term water security for 14,000 properties and will improve water security within the area for decades to come
- Refurbishment is preferable to construction, however not always possible. In this case, where a new build asset was unavoidable, we delivered carbon savings with smart building techniques including pre-cast concrete for the roof
- Applying off-site construction techniques also saved significant time and cost to our client
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