Sunday, March 6, 2016

one of Europe’s greatest unbuilt structures, Italy

the existing method of crossing the Messina Strait.
Italy is again considering starting one of Europe’s greatest unbuilt structures: the longest suspension bridge in the world, stretching 5.3 km across the Straits of Messina between Calabria and Sicily.

Angelino Alfano, the minister of the interior in the government of Matteo Renzi, announced on 10 September that he was preparing a “legislative initiative” to restart the scheme.

Alfano, who is Sicilian, said the plan was a vital part of a package of works to promote economic growth in southern Italy.

“I see no reason why we should not talk about the bridge over the Straits of Messina and we in parliament are introducing a bill to make it happen,” he said. “I know that the left will be against, but it will happen.”

The bridge has been a political football in Italy for a generation.

This latest revival caused friction in the governing coalition, with Francesco Boccia of the Democratic Party accusing Alfano, leader of the New Centre Right party, of raising the issue in an attempt to “survive”.

If built, the bridge would have a main span that surpasses by more than 1.3 km the currently longest spanning bridge, the Akashi Kaikyo Bridge. This would be an increase of roughly 65%. As it is meant to be a combined road and rail bridge, it would surpass the next longest bridge for the same use, the Tsing Ma Bridge, by nearly 2 km.

The greatest problem in designing the bridge is the aerodynamic stability of the deck under wind as well as seismic activity. A three-part box girder section was designed for the deck with the middle box carrying two railroad tracks and the outer boxes carrying the vehicular traffic. The three sections are connected by diaphragms at regular intervalls corresponding to the position of the hangers. The latter connect to a pair of main cables on each side of the deck.

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