26 August 2011

Outcry over plan to rebuild the Ponte dell'Accademia, Venice

A repeat of the battle between city authorities and traditionalists over Calatrava's bridge in Venice may be in the offing. Proposals have been announced to replace the Ponte dell'Accademia, which spans the southern end of Venice's Grand Canal.

I featured the bridge here last year. It's a steel arch bridge built in 1986, clad in timber to resemble the previous structure, Eugenio Miozzi's 1933 bridge. As I reported then, plans have been brewing for some time to improve disabled access over the structure which, like many Venetian spans, has steep steps difficult for many users to negotiate.

The latest proposal (pictured), from Bolognese architects Schiavina, is for a complete reconstruction. The new bridge would cost about £5m, and depending on which website you read, would be built either in glass, steel and stone, or in glass, steel and timber.

In support of the plans, the city council claim that the cost of maintaining the existing bridge is exorbitant, and therefore reconstruction combines the ambitions of reducing ongoing cost and providing access for all. A recent refurbishment cost about £220k, and the authorities consider the future costs to be unsustainable.

Preservationists are up in arms, with the president of a Venice heritage group crying "The bridge has a certain dignity. Why don't we just restore it?" At present, there's no final commitment to build the new design, which has been considered by the local authorities and sent to the heritage ministry in Rome for approval. Protesters are however probably mindful of the precedent set by the construction of Calatrava's Ponte della Costituzione, where concerns over its contemporary design were ignored (in my view, probably rightly, as it hugely improves accessibility in an area where many visitors first encounter the city).

It's unclear how the work will be funded, with Venice notoriously unwilling to dig into its own coffers to maintain the historically valuable fabric of the city (as seen here). One report has multi-millionaire Renzo Rossi covering the costs.

I don't know whether replacement is the right solution. As an engineer, the question must mainly come down to the sustainability of bridge maintenance: is it really in such a bad condition that it is too expensive to look after? It did look a little on the shoddy side when I visited, but so do many bridges, and I suspect the cost of maintenance is being exaggerated.

Venice argues that its 1986 reconstruction means it is no longer a historic artefact and therefore not deserving of heritage protection. I don't buy that at all. A considerable effort was made to preserve the general appearance of Miozzi's bridge when it was rebuilt - it maintains a continuity of appearance which should not lightly be set aside.

The bridge's context is also highly significant. While I'm no fan of attempting to preserve the environment in aspic, there are few places where the cityscape is of such historic (and economic) importance as in Venice. The bridge is a key gateway to the Grand Canal, and in a place like this there should be a very good reason indeed for changing the bridge's appearance so much.

It is also worth considering the technical difficulties that imperil every bridge in Venice, particularly the inability of the ground to support large foundation loads. The first bridge at this site was a simple metal truss, imparting only vertical load. Miozzi's wooden bridge was relatively lightweight, but at 48m span even that required a large number of both concrete and screwed timber piles. The current bridge is heavier, but a new steel and stone bridge will be heavier still. If the Schiavina proposal proceeds, expect a lengthy political battle followed by difficulties with cost escalation (it is far from apparent whether an engineer is yet involved).

Finally, I have to ask why only a single architectural firm has presented a design for this site. Schiavina are not noted as bridge designers, but if the case for replacement is ever proven, then surely a site such as this merits the consideration of design proposals from competing designers?

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