LONDON'S BATTERSEA Bridge re-opened to all traffic this week after damage caused by a barge strike last year was repaired three months earlier than expected.
The two outer cast iron arch ribs on one of the 120 year old crossing's five spans sustained serious damage when a 500t barge went through the wrong arch (NCE 29 September 2005).
It was closed to motor vehicles apart from buses until repairs were complete.
Time savings were achieved by telescoping the procurement process and getting main contractor Mowlem on site as early as possible, said Transport for London (TfL).
'We were already out to tender for work on the fascias of Westminster Bridge, ' said TfL chief engineer Dana Skelley. 'Because the work was so similar we were able to use the short list of three contractors for that job without going back to square one. This saved at least two months.' Repairs involved bonding 20mm thick mild steel plates to the underside of the lower flanges of the I section ribs.
Cracks extending well up into the webs were stitched together with the Metalock system of nickel steel 'multi-dumbbell' connectors.
Developing a repair solution was speeded by the use of a computer model developed by Travers Morgan, now Capita Symonds, during a strengthening operation in the 1980s.
This enabled TfL to rule out arch rib replacement which would have cost more and taken longer to complete.
Mowlem won the contract on 28 November and had a repair barge on station downstream of the damaged arch by 13 December. Work carried on through the Christmas period, with up to 16 men working between the arches.
'Our main problem was the cold weather, which could have affected the epoxy adhesive used to bond the plates, ' Mowlem site agent Jason Ruehland said. 'We solved that by using plenty of radiant heaters.'