0808 196 1460 info@pdmace.com

Surveying

PDMA is a well-established temporary works, civil & structural engineering consultancy providing bespoke services for the construction industry. We can now offer non-intrusive structural concrete surveys using the latest ground penetrating radar technology utilising HILTI portable PS1000 X-Scan equipment. This provides a quick reinforcement detection survey which can measure depth of cover, diameter and position of reinforcement bars within concrete up to a depth of 300mm from the surface. Bar location can be viewed live on site or the data taken off site and analysed to provide a survey report with detailed drawings.

We also offer a structural survey service recording intrusive structural break outs to provide precise details of actual reinforcement or steelwork. Every project is personally supervised by a Director; our Quality Assurance procedures comply with ISO 9001:2008, ISO 14001:2004 and our services are supported by comprehensive Professional Indemnity insurance. Our Comprehensive services includes rail surveys with a team of PTS trained surveyors with primary sponsorship in place enabling on or near line investigations to be carried out.

Above is an example of an intrusive survey on the left hand side and a non- intrusive survey mark up on the right hand side.

The following Ground Penetrating Radar (GPR) concrete scanning options are available to provide a range of bespoke services to meet the individual survey requirements using the Hilti PS 1000 X-scanner:

  • Simple strip scan up to 30m, with the bars marked on site for localised break outs/ drilling.
  • Grid scan either 600X600mm or 1200x1200mm with mark on site bar locations.
  • 2D & 3D scanning.
  • Provision of a written report and drawing to locate the scans for the above surveys.

Other concrete testing that we can provide (in conjunction with a UKAS accredited laboratory):

  • Compressive strength & Density.
  • Concrete composition & constituent parts (Concrete mix).
  • Chemical analysis including Sulphate, Chloride, Alumina, Calcium etc. Etc.
  • Cement content.
  • Carbonation.
  • Intrusive break out recording, reporting and detailing.
  • Overall appraisal of structural elements report on finding including recommendations.
  • Concrete coring
  • Structural element testing, analysis and reporting
  • Schmitt hammer structural concrete testing.

Above is an illustration of a non-intrusive wall survey composite of several 1200×1200 survey outputs for a 10m long wall.

Hilti PS1000 x-scanner GPR scanning principals

Ground Penetrating Radar (GPR) utilises a transmission antenna and receiver which send and receive electromagnetic waves into and from the subsurface. The transmitted waves are reflected, refracted and re radiated from subsurface features. By moving the scanner over a surface at a measured rate with the wheels rotation is used to provide a reference from which the received data is mapped against. The highly complex recorded data patterns is processed using sophisticated analysis software to provide mapping of the geophysical features including rebar, voids, services, conduits and cables etc. The penetration depth of a GPR system is limited by the antennae frequency with the following approximate maximum penetration:

Frequency 1500MHz 900MHz 400MHz 270MHz
Depth 0.5m 1.0m 4.0m 6.0m

Note: The greater the penetration depth the lower the resolution of the results obtained. The Hilti PS1000 has a working frequency of 2000MHz with a maximum penetration depths of 0.3m, which results in high resolution output results.