Post Tensioned Slab Cutting and Cable Truncation in Sydney
Post tensioned slab cutting in Sydney: Post tensioned slabs opened, truncated and reinstated
- GPR scan first, from the top and from underneath where needed
- Pockets held open for engineer sign off, then reinstated
- Every pocket photographed and numbered for the ITP
- Carbon fibre strengthening where the engineer specifies it
Penetrations through post tensioned slabs in Sydney, opened, truncated and reinstated to your structural engineer's design. Scanning, cutting, repair and strengthening under one contract, so nothing is lost between two subcontractors.
Why you cannot just cut a post tensioned slab
The tendons in a post tensioned slab were stressed after the pour and still carry that load. Open a penetration through one and you are working beside live steel that has held force since jacking. Cut the wrong strand without a plan and that force finds its own way out. Hitting a tendon is a structural event, not a repair. Every truncated tendon also takes capacity out of the slab, which the engineer must put back. So the scan and engineer sign off come before any saw starts.
How the work runs
- Scan and mark with the Hilti PS1000 X-Scan GPR, from the top and from underneath a beam where the geometry needs it. Tendons, reinforcement, conduits and depth are marked on the slab.
- Scanning report the structural engineer designs the truncation, pocket sizes, setout and strengthening from. We do not design or sign off.
- Open and clean each pocket to the approved size and setout with wall saws, core rigs or stitch coring. Water is managed so nothing runs to the floor below.
- Leave every pocket open until the engineer has inspected and signed it off.
- Epoxy fill and reinstate flush to the approved detail, then photograph and number every pocket for the ITP.
- Put the capacity back. Where the engineer specifies bonded carbon fibre, plate or wet lay up fabric, we install it under the same package with adhesion tests, batch numbers, temperature and humidity readings and photos handed over. Sika CarboDur S812 with Sikadur 30 has been installed on our jobs.
Typical jobs in Sydney
Lift and stair penetrations. Riser openings for hydraulic, fire, mechanical and electrical services. Escalator voids in towers and shopping centres. Slab removal for new plant. Fit out penetrations where a tendon sits in the way. Demolition of post tensioned structures, cut in engineered pieces and lowered by block and tackle or crane. Plant as on our specialist sawing and deep coring work: Tyrolit WSE1217 wall saw, Tyrolit WCE14 wire saw, Hilti DD350 and DD250 core rigs.
Safety and paperwork the head contractor wants
SWMS, inductions and quality records go into your systems and the pocket by pocket photographic record is built as we go. Where carbon fibre is installed the records pack covers substrate survey, moisture readings and adhesive batch numbers. We work on live sites in Sydney: operating hospitals, occupied buildings, night works, staged handovers and trading centres. Perfect Concrete Care is part of Perfect Group, with the insurance, licences and management systems a head contractor expects.
Where we work in Sydney
Post tensioned slab work in Sydney runs across the CBD towers and Barangaroo, North Sydney and St Leonards, Parramatta and Macquarie Park, the hospital precincts at Randwick, Westmead and Liverpool, Green Square and Mascot, Chatswood and Bondi Junction, and the shopping centre car parks and mixed use towers across the inner west, eastern suburbs and northern beaches.
The crew, scanner, saws and core rigs come out of our Marrickville base, so a scan can usually be booked within days and the cutting crew follows once the engineer has signed the setout.
Work near you includes infilling post tension pans across multiple levels at One Hurstville Plaza for Ganellan, wire sawing an 800mm thick slab in Pyrmont for penetrations and demolition and locating post tension cables across six levels at the Novotel Rockford, Darling Harbour, before the client cored. Each has its own project page.
Frequently asked
Do you cut post tensioned slabs for domestic clients in Sydney?
No. We work for head contractors, builders, structural engineers, facilities and strata managers and fit out contractors on commercial structures only.
Who designs the truncation?
Your structural engineer. We scan and hand over a report the engineer designs from, then the engineer inspects the open pockets and certifies the work. We do not design or sign off.
How deep can the scanner see the tendons?
The Hilti PS1000 X-Scan locates post tension and pre tension cables and their depth. Our scanning page quotes 320mm, and on one project we located cables up to 400mm deep. Where a beam is in the way we scan from underneath as well.
What happens if the scan finds more tendons than the drawings show?
It often does. On the hub example the drawings showed 19 tendons, the first scan marked 21 and a second scan from under a beam took it to 26, leaving 23 pockets after three at dead end anchorages were excluded. The engineer designs from the scan, not the drawings.
Other areas and related services
We also cut post tensioned slabs in Wollongong, Newcastle, Brisbane, Gold Coast and Sunshine Coast. Full method: tendon truncation. Related in Sydney: concrete scanning, carbon fibre strengthening, core drilling and concrete cutting.
What happens next
Call 02 8015 6398 or send the form below with the address, the drawings, the size and number of openings and the slab thickness. Ammar and the Sydney team run the job from our Marrickville base and will come back with a method, a programme and a price. If the engineer has not seen a scan yet, the scan is the first booking.
Need a price on this work?
Send us the scope and we will come back to you with a price. Commercial and industrial work only.
Perfect Concrete Care acknowledges the Aboriginal and Torres Strait Islander people as Traditional Custodians of the country on which we live and work. We pay our respects to the Traditional Custodians and Elders past, present and future, and honour their connection to the land and ongoing contribution to society.