Projects
130 piles into dolerite: the Macquarie Point pump station shaft
4 November 2026
A 23 m diameter secant piled tank in Hobart, excavated to RL minus 5.5 in fresh dolerite, delivered in a single piling mobilisation.
For the TasWater Capital Delivery Office, through CPB Contractors and UGL Engineering, BridgePro built the secant piled tank for the Macquarie Point Sewage Pump Station: 130 bored piles of 750 mm diameter forming a 23 m diameter shaft, each toeing 4 m into Jurassic dolerite, with guide walls, a capping beam with pile break-back, and excavation of the tank to RL minus 5.50.
The piles were installed as cased bored piles using segmental double-walled casing, with down-the-hole hammer gear on standby for obstructions and pile integrity testing on 10 per cent of piles. Groundwater was pumped to BridgePro’s own treatment facility. Excavation proceeded in fresh dolerite, with rock anchors installed to prevent flotation of the finished structure, the same approach proven at Davis Street in Smithton.
The programme ran to about 250 days with the piling completed in one mobilisation. Read the project page.
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