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Severn Bridge (M48) Refurbishment

South West England, UK · Ongoing (main cable inspection 2016; weight restriction from May 2025) · Approx. £2.4M (for main cable inspection, 2016 prices, converted from $3M)

The judgement call

Account-gated at launch

Decision to implement a weight restriction highlights critical structural concerns and the need for continuous monitoring. - Long-term maintenance and inspection programs are crucial for aging infrastructure to ensure safety and extend lifespan. - The economic and logistical impact of weight restrictions on regional transport and hauliers.

Key engineering challenges

Addressing significant corrosion in main cables. - Implementing a 7.5t weight restriction due to cable capacity assessment. - Maintaining structural integrity of an aging suspension bridge. - Managing traffic impact during maintenance and restrictions.

Project facts

Client / owner
National Highways
Lead contractor
American Bridge (for main cable inspection)
Lead designers
Project type
refurbishment | upgrade
Scale
2.22 km (1.38 miles) suspension bridge
Disciplines
Civil; Structural; Materials; Geotechnical
Standards & frameworks

Sources: National Highways: https://nationalhighways.co.uk/travel-updates/the-severn-bridges/ - American Bridge: https://americanbridge.net/featured-projects/m48-severn-bridge-main-cable-inspection/ - Wikipedia: https://en.wikipedia.org/wiki/Severn_Bridge - New Civil Engineer (2025): https://www.newcivilengineer.com/latest/national-highways-severn-bridge-cable-assessment-left-little-choice-but-weight-restriction-25-04-2025/ - UK Parliament (Written Evidence): https://committees.parliament.uk/writtenevidence/66930/html/