BBV’s second HS2 M6 South viaduct deck push: staging and traffic lessons for engineers
Reviewed by Tom Sullivan
First reported on The Construction Index
30 Second Briefing
Balfour Beatty Vinci is preparing to launch the 107‑metre, 1,250‑tonne west deck of the HS2 M6 South viaduct near Chelmsley Wood, sliding it 102 metres over the M6 junction 4 southbound slip road using a giant hydraulic jack onto concrete piers. The west deck, assembled in four smaller sections because of space constraints, staggered abutments and a curved loop road, will run parallel to the existing 320‑metre east deck installed in three stages under live traffic. Installation is planned in four phases from April to November 2026, with only the J4 southbound exit requiring closure.
Technical Brief
- Specialist hydraulic jacks will execute multiple incremental pushes, controlling movement of the 1,250‑tonne steel deck.
- West deck assembly requires four erection stages, one more than the east deck, due to reduced platform length.
- Staggered abutment positions and the adjacent loop road curvature constrain temporary works geometry and launch alignment.
- Phase one launch window is tightly constrained to 11–12 April 2026 for the first major slide.
- Phase two is fixed for 13 June 2026, with traffic maintained and no closures anticipated.
Our Take
BBV’s repeated use of long‑distance deck slides over the M6 and at HS2’s Delta junction, as seen in the 4,600‑tonne viaduct move reported in December 2025, suggests the joint venture is standardising strand‑jack and Teflon‑pad techniques for working over live strategic highways in the UK.
With HS2 works around the M6 South viaduct scheduled into April–November 2026, BBV is effectively locking in another major traffic management window on a corridor that National Highways and HS2 have already had to coordinate closely for previous junction 4–5 interventions.
Across the 777 Infrastructure stories in our database, HS2 features unusually often as a setting for complex staging (multi‑phase launches, Christmas and overnight possessions), and this M6 South viaduct sequence continues that pattern of pushing high‑risk structural operations into tightly constrained time slots rather than long closures.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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