Bridge investigations will bore 65ft into bed of Forth

A SECOND phase of ground investigation work ahead of building the new Forth road bridge will include boring 65ft into the river bed, Transport Scotland announced yesterday.

Engineers will also test ground conditions on either side of the bridge site, just west of the existing road bridge. The work, which starts this week, will help the agency leading the £2 billion project plan its construction, which is due to start in 2011 and take five years.

It will include a month-long survey of river bed conditions to test the sediment depth around the cable-stayed bridge's towers. The southernmost of the three towers is expected to extend 130ft below the waterline, including through 65ft of sediment above the bedrock.

Some boreholes and trial pits will also be dug on the south foreshore near the Port Edgar Barracks sea wall at low tide.

The land investigations, lasting around two months, will include the sites of connecting roads.