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Underground movement

Spotlight - Geophysical testing

Efforts to increase awareness of the benefits of radar and geophysical testing are starting to pay off as a growing number of clients take note of what the sector has to offer. Mike Walter reports.

Recognition continues to grow, in particular among streetworks contractors, of the value of underground mapping data produced by nondestructive methods of testing.

Now efforts are being made by specialist radar and geophysical contractors to spread the word to influential clients.

One major specialist is making moves to further the case for radar and geophysical works by entering talks with a leading transport authority to try and encourage it to promote more actively the work of nondestructive testing specialists.

Neil Bristow of geophysical company Geotec is in discussions with Transport for London's (TfL) street management directorate. 'We feel that regulatory bodies such as TfL should be more active in promoting the sorts of services we offer to consultants and contractors carrying out streetworks, ' he says.

'At the moment, the decision to employ a radar or geophysical specialist is left very much to the individual client or contractor, ' he adds. 'We would like to see authorities like TfL take a lead and introduce a policy document saying, for instance, that they strongly recommend employing the services of a geophysical specialist before excavation of a highway begins.'

Such a move would help prevent the unnecessary opening up of urban roads on a frequent basis, which can potentially damage underground utilities and disrupts traffic.

According to Simon Brightwell of Cambridge based specialist Aperio, ground penetrating radar (GPR) is a technique that has come of age as a standard highway investigation tool.

'Thousands of kilometres of road are surveyed each year in the UK and abroad. One recent survey funded by the World Bank and conducted by Aperio covered 24,000km of highway in Indonesia alone.

'Within the last year, the Highways Agency has updated the Design Manual for Roads and Bridges to provide recommendations for the use of GPR in providing pavement thickness and construction type data, and to a lesser degree for checking pavement conditions such as voids and delamination between layers.'

Aperio's technical director Sam Dods adds that clients are keen to use GPR because it covers the network at traffic speed, avoiding the safety and cost issues of lane closures while providing a continuous picture of the network that can be fed into computerised pavement management systems.

Another specialist keen to promote the benefits of nondestructive testing is the Lincolnshire based firm Adien.

Managing director Antony Norton is upbeat about the current state of the market. 'We are enjoying a phenomenal success but the problem is that we can't service the demand, ' he says.

'We are seeing an increase in the number of enquiries from utility companies, contractors, consulting engineers and councils as recognition of the environmental benefits of electronic detection over tradition excavation begins to pick up.'

Norton adds that the government has given added impetus to the call for radar and geophysical techniques to be used more widely on highways, with the introduction of Section 27 of the New Road & Streetworks Act as amended by the Transport Act of 2000. He says: 'The legislation gives highway authorities powers to levy charges of £100 to £2,000 per day for works that overrun. These penalties are already beginning to hit contractors, who are starting to realise more fully that using electronic surveys can minimise their exposure to these charges.'

Away from highways, partnerships are being signed between radar and geophysical specialists and contractors involved in the water and energy industries.

Neil Bristow of Geotec says: 'We recently signed a subcontract with Amec Capital Projects under its framework agreement with Welsh Water, and we are also an approved vendor for Transco.

'There is now better recognition in the water industry of the importance of good underground information to base design and construction plans on. In the past, when a contractor felt it had a particularly difficult job, we would be called in. Now, underground surveys are often regarded as of similar importance to overground surveys.'

Providing clients with a comprehensive geophysical service is of great importance to many specialists who not only carry out inspections, but also analyse and interpret data. One such company is the consultant Reynolds Geo-Sciences.

Operations director John Cubitt says: 'We provide a detailed understanding of the nature of any problem we are asked to investigate and come up with a set of appropriate technical solutions for clients.

'The tools and techniques used by the sector are evolving and there is a greater variety of equipment available. It is important for specialists to maintain the training of staff, however.'

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