Context

Due to increasing volumes of storm and wastewater impacting Yorkshire Water’s existing assets, a new storage tank was required to increase capacity at the wastewater treatment works. Aligning with commitments to reducing embodied carbon, constructing the tank entirely from concrete was not the preferred option; HDPE pipes were chosen, which also served to increase capacity.

The 4,300m3 tank was designed using 2.7m-diameter pipes arranged in 8 parallel rows, within a 25 x 108m footprint. Soil investigations identified potential groundwater at 4m below ground level, matching the tank's base. Although a concrete slab above the pipes had originally been suggested to counteract uplift, following calculations, Platipus was chosen as a Low Carbon Anchoring Solution (LCAS®).

Solution

The site was prepared by excavating to a depth of 4m and installing a 150mm unreinforced blinding layer, through which the anchors were subsequently driven. The Platipus Pipe Kit was positioned at 4m intervals, with a 2m offset applied to each of the 8 rows of the tank. A total of 444 anchors were installed, all of which were proof-tested to a load of 60kN to ensure stability.

Once the anchor installation was complete, the pipes were delivered, positioned in place, and immediately secured using Platipus Webbing Strap to prevent potential uplift. Following this the site was backfilled to finalise the installation process.

Result

By using the Platipus Solution only 4.2 tonnes of embodied carbon were emitted. Comparatively, the originally proposed concrete slab would have emitted 107.3 tonnes of embodied carbon. An overall saving of 103.2 tonnes of CO2e, or 96%, was achieved using the Platipus Low Carbon Anchoring Solution (LCAS®).