When heavy rain filled Lake Albert to almost full depth last year, the Wagga Wagga Boat Club had to rethink using concrete bored piers for the construction of their $50,000 entertainment deck.
Dan Perry from Perry’s Piles and Earth suggested using hot-dipped galvanised steel screw piles as an alternative. The 4M steel piles could easily be drilled above the water into the sandy lakebed.
An unknown was how the screw piles would react in the lakebed. The Project Engineer requested a trial after meeting with Katana Foundation’s Technical Product Specialist, Chris London. “We drilled a couple of test piles in Lake Albert late last year. The results showed excellent pressures in the sand, proving the concept, and allowing the Engineer and Project Manager to sign-off on the design”, said Chris.
The project required 21 screw piles to be drilled 2.3M deep into the lakebed, with 1.3M submerged in water and 0.4M out of water.
One of the challenges was getting access to install the piles. “A barge was not feasible, so we looked at using a 20-tonne excavator that could reach our far enough [7.5M] from shore to drill”, said Chris.
“But the only 20 tonner we had in the area was being used on another project, so we had to improvise”, added Dan.
Dan’s mate fabricated an arm extension jig to attach to his 13-tonne excavator. “It was a great innovation and worked really well”, commented Chris.
A slight inconvenience was somebody was going to get wet. “I was in the water to get the profiles straight. The deepest part was 1.3M, so it wasn’t too bad”, remarked Dan.