No bridges on the UK’s strategic road network bear similarities to that of the collapsed structure in Italy, Highways England (HE) has said.
Moved to respond to the catastrophe in Genoa, the roads operator said that while “a very small proportion” of its structures are suspension or cable stayed bridges, none were of a “similar construction” to that of the Polcevera Viaduct.
The unusual statement comes as concerns mount as to what the possible contributing factors were that led to the fatal collapse.
Italian road operator Autostrade has confirmed that the bridge was undergoing maintenance work when around 250m length of deck and a pier collapsed, killing 43 people.
The operator said it had been strengthening the structure’s foundations as part of scheduled maintenance works, although it is not yet clear where foundation work was taking place in relation to the collapsed section.
“The works and state of the viaduct were under constant monitoring and supervision,” Autostrade said in a statement.
The statement by UK counterpart said of its road network: “We have detailed design standards and quality control processes to ensure bridges are designed and constructed to provide safe and comfortable journeys for road users.
“This is supported by a thorough and regular regime for inspecting all structures, including bridges, on England’s motorways and major A roads and taking any necessary action to help ensure they stay safe.”
General inspections are undertaken every two years with more detailed principal inspections typically every six years, involving close inspection of all parts of a structure.
Questions are now being raised as to how such a devastating bridge collapse could happen in a European country, whose proximity to the UK appears to have triggered concerns around asset knowledge and safety here, which in turn has triggered HE’s assurances.
These assurances emphasise the UK’s confidence in the safety of its own key bridge assets. The Humber, Severn and Forth bridges – all major road crossings – have all been subject to serious maintenance interventions to stem cable corrosion. Dehumidification of tendons extensive acoustic monitoring keep the structures in service.
In addition, Transport for London was issued a stark reminder of the vulnerability of road structures when in late 2011 it closed the vital 1960s Hammersmith Flyover as a result of the discovery of a “serious structural defect” during a two-year detailed monitoring exercise. Scheduled repairs were made more urgent as the problem was revealed to be worse than earlier inspections indicated.
Around six months later, a nearby section of the M4 – known as Boston Manor Viaduct – was also urgently closed following the discovery of cracks in the 1960s’ steel structure’s electroslag welds.
On the local roads network, concerns remain as to the vulnerability of key structures. Research released by the RAC Foundation last year found that over 3,000 council-maintained road bridges were considered “substandard”.
Analysis of data received from 199 of the 207 local highway authorities in the UK shows that 3,203 structures over 1.5m in span were unfit to carry the heaviest vehicles, including lorries of up to 44t. This represents around one in 23 of the roughly 72,000 bridges on the local network.
Highways England said that it would seek to assess potential for lessons to be learned once the ensuing investigations into the causes of the Italy bridge collapse are complete, and a report issued.
“We can reassure drivers that safety is and always will be our top priority,” it added.
Autostrade said it intended for thorough investigations to be carried out once the site had been made safe.
UK’s strategic road bridges
Highways England has more than 21,000 structures on England’s network of motorways and major A roads, none of which are of similar design to the one in Italy, it has said.
A rigorous inspection regime is in place for all of its structures, according to the UK strategic roads operator Highways England. The regime takes into account design, age and the likely maintenance needs. General inspections are undertaken every two years with more detailed principal inspections typically every six years which involve close inspection of all parts of a structure.
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