Wire sawing the channel wall. Slurry captured at the cut with silt socks and pumped out for treatment.
A 23 metre long reinforced concrete wall opening, cut and lifted out in panels inside an operating Sydney Water asset. No impact breaking, no heavy plant in the channel, and the waterstops that keep the plant running left untouched 100 millimetres from the cut line.
The problem
New pre-treatment infrastructure had to tie into Channel 1, a raw water channel that feeds the Prospect Water Filtration Plant. That meant opening a reinforced concrete wall 23 metres long and 4 metres high, tapered from 480 millimetres thick at the base to 300 millimetres at the top, plus cutting four discharge penetrations of 1,400 by 2,000 millimetres through the same wall.Sydney Water's conditions ruled out every blunt method. No heavy mechanical plant was allowed inside the channel at any time. No demolition saws and no impact breaking. Every cut had to hold a minimum 100 millimetre standoff from the construction joints, because the PVC waterstops inside those joints had to stay intact. Damage the waterstops and you compromise a live water asset.The methodology
This is the kind of scope where the engineering matters more than the machine. The wall was divided into seven panels with eight buttresses, each panel sized to the crane chart rather than to what the saw could manage. Stitch cores were drilled at the cut intersections first, so no cut could ever run past its termination point. Panels were then freed with diamond wire and wall saws and lifted out in sequence by a 400 tonne crane, with the temporary works design certified by a chartered structural engineer before the first cut.Cutting ran around the clock. Because diamond cutting is vibration free, the retained structure, the bottom slab and the adjoining new concrete were never put at risk, and the plant kept operating throughout.
Track-mounted wire saw at the wall. The stitch cores that stop any overcut are visible at the corner of the opening.
Water and slurry, handled properly
Cutting concrete with water inside a drinking water catchment asset leaves no room for shortcuts. Slurry was contained at each cut with physical barriers and silt socks, collected, and disposed of through EPA licensed facilities. Waste was separated by stream: concrete to a recycler, steel to a scrap recycler, slurry to a licensed liquid waste facility.Why it matters if you are planning similar work
Most cutting contractors can put a wire through a wall. The value on a job like this sits in what happens before the cut: a written methodology the client's engineers can review, panel weights matched to crane capacity, stitch cores that make an overcut physically impossible, and a slurry plan the EPA would be happy to read. That is the standard DeconCut brings to every industrial cutting scope.Related services: wire sawing and structural cutting, cutting engineering and methodologies.Planning a cut inside a live asset?
Send us the drawings and constraints. We will come back with a methodology, not just a price.
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