Atkins told to pay £800k after Hochtief-Volker road claim
The Cliffsend Underpass (image: Volker Fitzpatrick)
Atkins has been ordered to pay a joint venture between Hochtief UK and Volker Fitzpatrick more than £800,000 following a dispute over drainage on a new section of dual carriageway in Kent.
The dispute centred around the £87m East Kent Access Road Phase 2 project for Kent County Council, which involved the construction of two new dual carriageway roads, the A256 and the A299.
In 2009, Atkins was engaged as a subcontractor to complete the civil and structural design elements for the Cottington Road Bridge, a two-span bridge carrying the A256 dual carriageway over a road and railway line, and the Cliffsend Underpass, a 120m-long tunnel under the railway line to accommodate the A299 dual carriageway.
But following completion of the bridge in 2011, surface settlement of the carriageways on the north and south sides of the approach embankments was discovered, which required remedial works in 2012 and 2014.
Meanwhile, the underpass was completed in March 2012 and signs of leakage were found on the western end in April 2012, including rust staining on the headwall beam at the west end, icicles above the carriageway and fine cracking of the concrete face of the headwall, which required remedial works in 2013.
In 2017, the Hochtief/Volker Fitzpatrick JV issued proceedings against Atkins for breach of contract and/or negligence in carrying out the design of the structures and claimed damages of £802,475.35 in respect of remedial works to the bridge and £122,559.82 for remedial works on the underpass.
The design of the bridge incorporated a stepped layer of lightweight fill material, Filcor, into the general fill supporting the abutments. The Filcor was made up of expanded polystyrene cube (EPC) blocks, which were covered by sheets of high-density polyethylene membrane to prevent damage from fuel spills from vehicles using the road.
The JV claimed that Atkins failed to design or specify any adequate system of drainage of sub-surface water from above or adjacent to the membranes. This, it claimed, allowed excessive water penetration into the chalk fill, causing softening and collapse compression of parts of the general chalk fill of the embankment approaches, resulting in differential settlement of the carriageways.
For its part, Atkins argued that the general pattern of settlement was not collapse settlement but foundation settlement that was expected in such construction. It said it provided for adequate sub-surface drainage in its design and that local depressions were caused by workmanship issues – namely the JV’s failure to lay the membrane to the required line and fall.
When it came to the underpass, the JV claimed that water leakage was caused by Atkins’ failure to design or specify an adequate waterproofing system for the joints between the elements at the west end of the underpass.
The JV acknowledged that there were deficiencies in its workmanship including voids in the grout full but argued that properly applied grout would not have prevented the leakage.
Atkins countered that the leakage was caused by the JV’s failure to remove parts of steel “anti-drag system” (ADS) sheets that had been used in the construction of the underpass. The underpass, which has a roof/deck 1.8m deep and is 21.6m wide was at the time one of the longest jacked structures of its type in the world. Each deck was jacked into position from the west end of the underpass, pushed along concrete slide-paths, one on each side of the structure.
A huge amount of jacking force was required to push the decks into place. To accommodate this, the ADS was designed to reduce friction between the top of the decks and the ground above. The ADS comprised pairs of steel sheets, each one metre wide, sandwiched along the length of the underpass. An anchor headwall beam was built first, to hold the ADS sheets. The decks were then jacked beneath the beam.
During the jacking process, the steel sheets were slid along each other to reduce the force needed to push the decks into position. Bentonite slurry was injected above the tops of the decks to lubricate them during installation. Following completion of the jacking process, in situ concrete head walls were constructed.
Atkins also argued that the JV failed properly to install grout in the 100mm void between the roof section nearest the end of the underpass and the headwall anchor beam.
At the Technology and Construction Court, Mrs Justice O’Farrell found in favour of the JV’s claim relating to the bridge and awarded damages against Atkins of £802.475.35.
But she found that the JV failed to prove its claim in respect of the underpass and dismissed it.
Atkins declined to comment.