Bridge collapses have been an ongoing topic for NCE’s news team right from the launch issue. The collapse of the Polcevera viaduct on the A10 in Genoa, Italy on 14 August 2018 killing 43 people and injuring a further 16 sent shockwaves through the industry.
It happened just as we were putting the August 2018 issue to press and Mark wrote in his leader for that issue that a structure such as the Polcevera viaduct “should never, ever collapse. Anywhere in the world. It should certainly never happen in a western European country such as Italy”.
Investigators concluded that the highways operator Atlantia was guilty of “serious and unforgivable
acts of negligence” with severe corrosion found in the concrete covered cable stays.
More than 50 in trial
Italian prosecutors plan to put more than 50 people on trial for the failure, including senior executives of Atlantia subsidiaries engineering firm Spea and bridge operator Autostrade per l’Italia. Prosecutors have said that “even a pensioner could have seen that the bridge had problems”.
What should be said is that the Polcevera viaduct was amazing in its time and its designer, Riccardo Morandi, was a genuine innovator. NCE’s founding editor Sydney Lenssen visited the Genoa viaduct when it was under construction in 1965 and insists that it was a miracle in its day. Sydney recalls that, despite reservations about the unusual design, Morandi’s ambition was infectious and he was heralded as a genius at the time.
Morandi was determined to explore the concept that evolved into cable-stayed technology and was equally determined to push the use of prestressed concrete. Clearly it would never be built in the same way today. Cable-stay technology has massively advanced. But that does not mean that Morandi built a bad bridge.
Over the weeks that followed the collapse it emerged that Morandi’s bridge had required considerable maintenance over the years with pictures clearly showing strapping around many critical beams. There were also plans to strap the section that failed.
There is no shame in that: many bridges of that era are in the same situation, principally because no bridge designers of that time foresaw the long term durability issues and excessive traffic loads that would affect their structures. No one did.
While the collapse and the lack of maintenance that led up to it cast a dark shadow, the work to design, build and open a replacement bridge within two years was a real high point. The successful delivery of the new structure demonstrates what can be done in a short period of time when there is true collaboration between the client, consultant and contractor.
The new bridge – named the Genoa-Saint George Bridge – was built by a joint venture of WeBuild (formerly Salini Impregilo) and Fincantieri with Rina Consulting as project manager for the programme. The structure was designed by architect Renzo Piano and features a 1,067m steel deck spread over 19 steel and concrete spans, which vary in length from 26m to 100m, with the majority measuring 50m.
The new structure has a plaque remembering the 43 who died when the original bridge collapsed but it is essential that civil engineers continue to learn lessons from such tragic incidents as this.
- This article was written by Claire Smith on behalf of Mark Hansford
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