BG&E designed the Ellenbrook Water Tank, an 80-million-litre above-ground concrete drinking water storage tank, the largest built for the Water Corporation at its completion in 2018.

The tank ensures a reliable drinking water supply for Ellenbrook and the surrounding north eastern metropolitan corridor.

The tank, with an external diameter of over 91 metres and a height of approximately 13 metres, was constructed from prestressed concrete. It features an in-situ post-tensioned base slab and precast wall panels. The structure is covered by a lightweight steel roof supported by 13 internal precast columns.

The base slab was constructed in a single 92 metre diameter pour, involving approximately 1,260 cubic metres of concrete placed over 11 hours. Early staging of the base slab post-tensioning enabled construction without thermal or shrinkage cracking.Georgiou engaged BG&E for the detailed design of all concrete elements.

The scope included

• A combined base slab and ring beam cast in-situ in a single 6750-square- metre pour with bi-directional post-tensioning tendons and no conventional reinforcement.
• Tank walls made of 80 precast, vertically tapered and pre-tensioned panels – including special panels for access manholes and post-tensioning anchorage pilasters. Panels were stitched in-situ, then circumferentially post-tensioned.
• An innovative wall-to-base slab detail to resist Importance Level 4 seismic actions.

The Ellenbrook Water Tank sets a new standard for large above-ground water storage with its efficient structural detailing, post-disaster functionality, and strict cracking limitations for 100-year unlined potable water containment.