ENGINEERS LOOKING for ways to re-use existing piled foundations are facing a number of new challenges. In finding the old piles, do construction drawings exist, and are the piles all where they should be? Once locations have been identified engineers need to assess what state the piles are in and whether they can take the new loads.
Geophysical techniques, such as highresolution magnetometry and pile integrity testing, are helping to provide many of the answers.
Geophysics is also a powerful tool for the detection of general obstructions in the ground and even clearance of unexploded Second World War bombs - which remains an important health and safety issue in certain parts of the country.
Geophysical specialist Zetica has put together a team, including cone penetration testing contractor Lankelma and site investigation contractor Norwest Holst, providing complementary activities focused on investigating old piles.
Frequently working with Arup, Zetica has been involved on a range of redevelopment projects including Battersea power station, Beckton gasworks and Royal Arsenal Woolwich.
Zetica's Dr Asger Eriksen says 'the noninvasive methods being used at major brownfield sites are helpful in locating old piles, determining their depth and checking their integrity so they can be re-used'.