CONTACT

Existing Footings Investigation – Noosa Heads QLD

CLIENT

Elite Contruction & Maintenance QLD

LOCATION

Noosa, Sunshine Coast

YEAR

2025

The Problem

The consulting engineering firm engaged GP Structural Services to investigate the integrity of the reinforced strip footings and slab at a residential property in Noosa Heads. Concerns were raised about footing reinforcement continuity and overall concrete strength, as the structure was being assessed for suitability under proposed loading upgrades. A detailed non-destructive investigation was required to map reinforcement, measure slab composition, and evaluate compressive strength without destructive coring.

Our Approach

Ground Penetrating Radar (GPR) Scanning was undertaken across semi-exposed strip footings using PS1000 equipment.

  • Confirmed footing dimensions of approximately 250mm x 450mm.
  • Identified N20 reinforcement bars top and bottom, with 60–90mm cover.
  • Verified slab thickness in the range of 200mm.
  • Checked for structural anomalies, voids, or honeycombing, supported by digital 2D & 3D mark-ups.

Schmidt Hammer Testing was conducted across five locations on the footings.

  • Ten measurements were recorded per location using a calibrated Proceq hammer.
  • Surface rebound data provided an estimate of in-situ compressive strength.
  • Results indicated a compressive strength range of 28.7–34.5 MPa with an error tolerance of ±5.5 MPa.
  • An averaged result of ~32 MPa was calculated across the test series, demonstrating acceptable strength for residential footing applications

All results were consolidated into compliance-ready reports, combining structural reinforcement mapping and compressive strength evaluation for engineering review.

THE SOLUTION

By integrating GPR scanning with Schmidt Hammer testing, GP Structural Services provided the client with a comprehensive assessment of both reinforcement detailing and material strength. This dual methodology enabled informed engineering decisions without the delays and costs of destructive coring, ensuring the project could progress with confidence.

In this case, the design engineer was able to confirm the existing footings would not be suitable supporting the integrity under proposed loads.