How we use decades of research to implement cost-effective structural solutions

Ground-penetrating radar (GPR) has enormous potential for use in analysing engineered structures without using invasive techniques that could impact the structure. In conjunction with RSK’s structures and materials teams, we have conducted numerous investigations aimed at determining construction detail and internal metalwork in a variety of modern and historic buildings, including tunnels (both concrete and masonry construction). This has resulted in us accumulating a large database of GPR reflection data for various structural features and faults, which is used to improve our structural survey capabilities and techniques. Using GPR with a range of frequencies enables rapid non-destructive coverage, with a depth penetration of up to 2 m. The approach allows us to image multiple layers of construction detail, calculate thicknesses and locate voids and internal metalwork, including multiple layers of reinforcement.

Slab thickness

High-frequency, high-resolution GPR surveys provide a non-destructive testing tool for concrete and other construction materials, enabling their internal structure and potential flaws to be imaged in situ without coring or breaking out.

Depth of screed

Screed is the top finishing layer on a concrete slab. GPR can be used as a reliable, rapid, non-destructive means of testing the thickness of the screed over large areas.

Detection of internal metalwork

Traditional cover meters are somewhat limited in their penetration depth and application to detect complex reinforcement arrangements. A high-frequency GPR system, utilising a 900 to 2000 MHz antenna, can provide high-resolution data to depths of 1 m and record the data to provide a permanent record of reinforcing mesh, as well as allow further processing to be completed in the office to increase the level of detail of the survey.

Detecting voids

GPR has been used very effectively in locating cavities and voids within structures. High-frequency GPR allows rapid, non-destructive coverage that is capable of imaging multiple layers of construction detail.

Benefits of GPR structural investigations

  • Non-intrusive and non-destructive to structures – preserves the fabric of the object being tested (works well on stone and concrete)
  • Minimal disruption to building occupants or the public
  • Rapid – high-speed acquisition provides quick and reliable information across large areas
  • Continuous measurement rather than point samples
  • Reduced project costs and risks – reduces the need for expensive or disruptive intrusive investigations

Other geophysical survey applications

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RSK Geosciences is part of the RSK group of companies

The RSK group is a leading integrated environmental, engineering and technical services business offering bespoke end-to-end solutions to a variety of sectors. Headquartered in the UK but with an established presence throughout Europe, Africa, the Middle East, Asia and Australia, RSK helps organisations around the world achieve their business aspirations in a sustainable and efficient manner.