Henley High School, SA

CLIENT

Adelaide Structural Engineers

LOCATION

Angle Vale, SA

YEAR

2025

The Problem

GP Structural Services were engaged to undertake a Ground Penetrating Radar (GPR) investigation across both the ground and first-floor toilet slabs at Henley High School. The objective was to confirm reinforcement layout, slab thickness, and construction type, and to assess whether post-tension (PT) cables or anomalies were present prior to proposed design works.

Our Approach

High-resolution GPR scanning was carried out using PS1000 and PS300 Ferroscan equipment.
Investigations covered multiple slab areas, with targeted scans on male and female toilets across both levels.
Structural data recorded included: reinforcement type and cover, slab thickness, and decking configuration.
Electromagnetic detection (EML) was integrated to identify subsurface power conduits.
Digital markups and imaging (2D & 3D) were prepared to visualise reinforcement and highlight potential risks.
Limitations were noted, as corrugated iron sheeting within the slab reduced the radar’s ability to confirm underlying foundations.

THE SOLUTION

The investigation confirmed that all slabs were approximately 100mm thick with single layer SL82/92 mesh reinforcement, generally located with 70–90mm top cover. Visual inspection confirmed that slabs were poured over corrugated iron decking supported by steel trusses at 600mm centres. Importantly, no post-tension cables or significant anomalies were detected.

The findings gave our clients engineering consultancy confidence to proceed with future design works, ensuring safe planning for penetrations and upgrades while avoiding the risk of striking live services or reinforcement.