How embracing engineering challenges unlocked the reduction in embedded carbon at the SSTC3 Soil Nailing project-PPT Presentation

PPT Presentation

Pdf Summary

The Sunderland Strategic Transport Corridor 3 project involved constructing a 250-metre highway section beside the River Wear, where variable ground included poorly compacted backfill, glacial clay and limestone.<br /><br />The compliant design used a combi-wall of steel piles and sheet piles, supported by ground anchors. A 12-metre-high soil-nailed slope was adopted instead, using 1,734 nails up to 16 metres long, with mesh, geotextiles and a gabion finish. This alternative required careful management because ground and groundwater conditions were uncertain, and excavation created risks of instability and erosion.<br /><br />Construction revealed buried shipyard foundations, drainage channels, large concrete obstructions and asbestos-containing material. The slope crest was also lower than specified, and erosion and local face instability occurred. The team responded by revising nail layouts and spacing, relocating nails around obstructions, repairing erosion, and maintaining close communication and site supervision.<br /><br />The presentation attributes the successful outcome to early sustainability planning, robust investigation and risk controls, supply-chain support, and willingness to adapt the design. Compared with the compliant scheme, the installed solution reduced estimated embedded carbon from 3,693.3 to 1,057.6 tonnes of CO₂e—a 74% reduction. It also delivered cost savings and a shorter programme. Carbon estimates were calculated using the EFFC-DFI Carbon Calculator and assumptions about recycled steel content and plant fuel use.

Keywords

Sunderland Strategic Transport Corridor 3

River Wear

soil-nailed slope

combi-wall

ground anchors

embedded carbon reduction

construction obstacles

groundwater conditions

sheet piles

EFFC-DFI Carbon Calculator