Pylons of Messina
The pylons are two 200 metre high freestanding steel towers, one on Sicily and the other on the Italian mainland. In a difference from usual practice, the corners of the pylons are arranged diagonally along the direction of the course of the line. The pylons of Messina were the model of the pylons of Elbe crossing 1 in Germany and were, until the completion of Elbe crossing 2, the highest pylons of the world.
After their completion, the duration of the oscillation of the structures and their elongations were determined in a very unusual manner: engineers mounted three rockets with a thrust of 9800 kilonewton on the tops of the pylons and ignited them! (Source: Turmbauwerke, Bauverlag GmbH, Wiesbaden, 1966)
Because the overhead power line over the Strait of Messina has a very large span width (more then 3 kilometres), and because of maritime traffic in the strait below, the conductors must have a great minimum height above ground, and would have spun very strongly. This required the use of steel cables as conductors, which have the disadvantage of less electrical conductivity then normal overhead power lines. The danger of oscillations caused by wind did not allow the usage of bundle conductors. Thus, the original overhead line across the strait did not meet modern operational standards, and it was replaced at the end of the 1990s by a submarine cable.
The now-unused pylons remain, with protected status as historical monuments.
- Messina Straits High-Voltage Pylons (including picture)