Stabilzing a Sidehill Cut at central Freight Terminal
The Daventry International Rail Freight Terminal (DIRFT) is a freight depot and logistics center that is centrally located between Birmingham and London and directly linked to the European continent via the Channel Tunnel. DIRFT is in immediate proximity to Great Britain’s most important motorway and railway links and is one of the most important freight terminals in the country.
The area, which was originally established in 1997, is being expanded by a total of 54ha on which several bridges, streets and railway tracks will be built in addition to warehouses and industrial buildings.
Due to the grade separations between the incoming rail lines, access for road freight and hard standing areas, a number of retaining walls were required. One of the largest retaining walls consisted of a contiguous pile wall, tied back with permanent DYWIDAG Tie Bars (Tie Rods).
The permanent tie bars consisted of 50mm GEWI® steel threadbars in lengths of 12-22m with couplers, domed nuts and countersunk bearing plates. At the dead end, the tie bar was anchored in a deadman consisting of a precast bearing pad embedded in the ground beyond the active wedge zone.
At the live end, the tie bars were terminated on short length galvanized waler beams to ensure that the load in the tie bar was spread between two piles in the contiguous wall.
Durability of the tie bars was ensured through the incorporation of sacrificial corrosion allowance. This mechanism allows for sufficient section of steel to enable corrosion to occur without compromising the steel section required to fulfill the design load of the tie.