Tregenna Villa Retaining Wall St Ives - Piling & Anchoring

Tender description

Corserv on behalf of Cormac Solutions Ltd are seeking to appoint a competent and experienced contractor for the supply of all plant, labour and materials required for the installation of piles and tension anchors, as set out in the specification (available upon receipt of expression of interest) in accordance with the current standards and regulations. Full copy of test results and site records to be issued as per the specification upon completion. Tregenna Villa retaining wall is approx.. 5m in length, running from the top of the steps at Tregenna Terrace to the corner of No. 1 Tregenna Villas (Kittiwake Cottage). The wall collapsed in April 2017 - there was no adverse weather at the time of the collapse. The existing structure was constructed using drystone masonry with a cast iron handrail above. Site Investigation has shown that there is voided, loose fill to a depth of 4m below ground level where they encountered refusal at bedrock which was Blue Elvan. The proposed strengthening solution is to drill 12 no. vertical 140mm diameter micro-piles at 400mm centres into the bedrock and rake two 20mm diameter stainless steel tension anchors below the boundary wall of Pednolver Terrace. Stability of Pednolver Terrace wall and collapsed material of Tregenna Villas are to be monitored during piling operations. The embedment of the vertical piles in to the bedrock will be 2.5m with a rock socket of 500mm. The raked anchors will be embedded by a minimum of 3m into bedrock.