Northpoint assists the local authority by completing a geotechnical investigation. Works are for a new bridge crossing over the busy A689 dual carriageway.
Working in partnership with the local council, we carried out a geotechnical investigation for a highway crossing over the A689 in Wynyard.
Recent and ongoing significant development is taking place in the area. This includes vast areas of new housing, commercial promises and areas of recreation. The A689 by its nature is a busy and major highway link between the A19 and A1(M). The new crossing will connect both areas to the north and south of the A689.
The geotechnical investigation included trial pits and cable percussive boreholes to characterise the underlying soil and rock deposits to aid foundation design. Information from the investigation included gathering sufficient geotechnical parameters to assist with detailed design.
Overall, favourable ground conditions were recorded. These included Glacial Till and Sandstone. The Till deposits are clay materials placed by glaciers and ice-sheets approximately 2 million years ago. The Till overlies solid geology of sandstone, which in contrast formed over 250 million years ago. The boreholes and trial pits we placed to determined whether the Till or much older and harder sandstone would be more suitable to safely take the weight of foundations and the bridge crossing.
Northpoint worked alongside structural and civil design engineers to provide a cost-effective foundation solution. Consequently, foundations included piles to support the crossing. This was due to the bridge loading conditions and variable geology.