Kvaerner Construction is currently engaged on various essential line repairs and reconstruction projects for Railtrack in the North of England.
At Horsfall Tunnel, on the Manchester-Normanton line, it has recently completed a £1.4 million rebuilding scheme to improve train services, while in Newcastle and County Durham it is embarking on a string of projects stretching into 1999 and valued at £3.1 million. Both schemes were secured on a design-and-construct basis.
The western end of Horsfall Tunnel has been rebuilt after an intense round-the-clock winter operation involving removal of a deformed lining section at the Todmorden portal and extensive re-profiling of the hillside.
Demolition and reconstruction of the tunnel was carried out in a four-week continuous railway possession. Some 140 metres of existing track were removed and 30 metres of tunnelling demolished. Around 5,500 cubic metres of excavation and overburden materials were removed in a non-stop operation lasting 96 hours.
To ensure safe working during reconstruction, Kvaerner Cementation Foundations supported the adjacent hillside by installing a reticulated mini pile wall as a temporary retaining structure. More than 330 200mm-diameter minipiles 16 metres deep, connected together by a reinforced concrete pile cap, formed the retaining wall, which was installed from above the tunnel before the track closure, to minimise disruption to rail traffic.
At up to 14 metres, it is believed to be the highest structure of its kind ever constructed in the UK. Additional inclined ground anchors were installed at the highest sections to prevent potential buckling, and soil nailing above the existing tunnel stabilised loose ground.
Once demolition and earthworks were completed, round-the-clock operations focused on rebuilding the tunnel with a new concrete portal.
Over 18 days, 1,300 cubic metres of concrete was pumped, 240 tonnes of reinforcing steel installed, and 33 tonnes of temporary support girders erected to form the tunnel base, walls and roof slab.
Kvaerner Construction project manager Keith Gardner commented: "The structure was finished and the line reopened on schedule. The end of long-standing speed restrictions along this stretch means improved journey times for passengers."
A key factor in the success of the operation was a partnership agreement between Kvaerner Construction UK Civils and Kvaerner Cementation Foundations. This led to Railtrack awarding a further £850,000 of embankment stabilisation work at Kitson Wood nearby.
In addition, Railtrack has chosen Kvaerner Construction to carry out a further package of remedial works in the North East. Work is now under way on four viaducts carrying the East Coast main line - at Chester le Street, Chester Moor and Plawsworth in County Durham, and at Dean Street, Newcastle.
The contract, involving deck-waterproofing and drainage works, brick and masonry repairs and arch strengthening, is being carried out in phased track possessions during off-peak periods, including Christmas and Bank holidays. Kvaerner Cementation Foundations is again assisting with these contracts by using long range grouting techniques to consolidate these viaducts.
For further information contact:
Cheryl Eaton, PR Manager - 01923 423 030Tanya Barnes, PR Officer - 01923 423 905