Scottish Trunk Road NMC - North West - A835 55 W47 Loch Garve Wall

Tender description

The existing Loch Garve Wall supports the A835 trunk road at the top of a steep embankment, at the bottom of which runs a Network Rail line. The works include the construction of a new 108m long reinforced ground beam supported by a combination of hollow steel mini-piles and sub-horiztonal anchors (-20°) socketed into bedrock. Space for placing drilling rig is restricted due to the narrow carriageway and steep slope. Tenderers must consider suitable plant for drilling when inspecting the drawings. The ground beam will be constructed in (11 no.) 9m sections separated by movement joints. The ground beam consists of a 1m x 1m cross-section and additional 0.82m wide cantilevering edge beam and upstand that supports a high containment H4a steel parapet. A Temporary Works design for ground beam formwork and rockfall protection fencing will be submitted to Network Rail for approval, in line with their standard procedures. Each 9m ground beam section will be supported by 13 no. piles and 8 no anchors. The bottom face of the ground beam will be supported by formwork below, as opposed to blinding, to physically separate the new beam from the existing masonry wall. The top 1m height of the existing masonry wall, that supports the trunk road from below, will be demolished to make way for the new ground beam. Cores through the remaining masonry wall will be made for drilling the vertical mini-piles. New kerbs and footway will be constructed. The existing BT Openreach cable that runs adjacent to the wall will be locally slewed away from the works by Openreach, then reset to its original alignment on completion. Principal Quantities: Steel Reinforcement – 14 tonnes (20mm & 16mm diameter bars) In-Situ C40/50 Concrete – 168m3 Hollow Steel Mini-Piles (111mm diameter) – 117 no. Hollow Steel Anchors (51mm diameter) – 72 no. 6N Fill to Structures – 168m3 Work Series: 200 Site Clearance (Masonry wall removal) 600 Earthworks (Piles and Anchors) 1100 Kerbs and Verges 1700 Structural Concrete 2400 Brickwork, Blockwork and Stonework