THE ROLE of an innovative piling system is being investigated as part of an inquiry into the causes of settlement in a fouryear old warehouse in Kent which began sinking shortly after it was built.
Consultant WSP has been engaged to identify why the warehouse at Crossways in Dartford is moving. It is occupied by French motor distributor Gefco, part of the Citroen group.
The building was constructed by Jarvis in 1996 and is founded on precast piles installed by specialist Roger Bullivant. According to sources on site, it is claimed that settlement of up to 150mm in places began just after occupation.
The floor slab is cast directly onto around 400 RB precast piles, forming a continuous structure.
Investigations are focussing on the piles, which use a novel glued socket connection between sections, and integrity tests have been taken.
While all areas of the warehouse are still in use, Gefco is understood to be concerned about stacking pallets on the uneven floor, particularly as it fears the building could settle under further load.
'The slab was poured directly onto the piles and underpinning is not an option, ' said a Gefco source. 'It seems to be getting worse, and is now noticeable outside as well as in. If it gets worse the building may have to be demolished, ' he said.
The glue-jointed piles are cheaper than other systems with standard mechanical joints between pile segments. Their use is governed by an Agrement certificate.
However, it is believed that investigators are not just looking at the joints as a cause of failure as it is understood that there are complex geotechnical conditions on site.
No one from Bullivant was available for comment and none of the other parties would comment because of possible litigation.
The RB Precast piling system is the subject of an ongoing investigation by the Federation of Piling Specialists after five member firms lodged complaints when failures associated with the product came to light last June at four sites in Cheshire and London.