Concrete Isn’t Always What It Seems
Concrete might appear as a solid block, but beneath the surface lies a network of reinforcement, cables, and conduits. Cutting or coring without knowing what’s inside is a gamble — one that can result in injuries, costly damage, and structural failures.
The Risks in Detail
- Post-Tension Cables – Severing a tensioned cable can release energy equivalent to a car crash. In Australia, Safe Work NSW has reported multiple near-misses and injuries linked to improper identification of PT systems.
- Electrical Conduits – Damaging a live conduit can cause electrocution or fire. According to Safe Work SA, electrical incidents remain one of the top three causes of workplace fatalities in the construction sector.
- Reinforcement Bars – Cutting through structural reinforcement can reduce load capacity and create long-term durability issues.
- Voids or Anomalies – Coring through an undetected void can lead to structural instability.
Why Scanning First is Essential
GPR scanning provides a non-invasive way to detect:
- Reinforcement mesh and bar spacing
- Post-tension cable locations
- Embedded services such as power or water
- Slab thickness and construction type (e.g., BONDEK, precast, or in-situ)
By combining scanning with Electromagnetic Location (EML), even live power conduits can be traced.
Case in Point
On a recent Adelaide project, GP Structural Services was engaged to scan a suspended slab prior to cutting penetrations. Our scan revealed multiple conduits with live power within 40 mm of the surface, which had not been documented correctly on the drawings. By adjusting the core locations, the builder avoided damaging reinforcement — saving thousands in potential repair costs and preserving the existing infrastructure.
The Bottom Line
Concrete scanning isn’t just a precaution — it’s a critical step in ensuring safety and compliance. With Australian construction sites under increasing scrutiny for safety performance, scanning before you cut is both a legal and practical safeguard.