Ponte Girevole (Taranto)
in Taranto, Italy
The Ponte Girevole is a swing bridge in Taranto, Italy, spanning the navigatible canal between Taranto's Mar Grande and the Mar Piccolo. The bridge connects Borgo Antico (Old Town) island to the Borgo Nuovo (new Town) peninsula. A steel bridge was first built across the canal in 1886, hydraulically operated using water stored in the Castello Aragonese. The present steel bridge was built in 1958. Officially titled the Ponte di San Francesco di Paola, the bridge has two swing spans. The 1958 replacement was designed by the National Society of Savigliano and built in the former Tosi shipyard in Taranto.
Engineering 1887/10/14 provided a very brief description, describing it as a 'lifting bridge', constructed by the Impresa Industriale ltaliana di Construzioni Metalliche, at Naples, of which Mr. A. Cottrau was the director. Some drawings were provided in Engineering 1887/10/28 (see above). More drawings and a slightly more detailed description were provided in Engineering 1887/11/11, but the article leaves many questions unanswered. It refers to 'the simplicity of the hydraulic mechanism employed for opening and closing the bridge. In fact the power unit is simple (water from a reservoir is admitted to a water turbine by a manual valve, the turbine and valve being located in the masonry base below each of the two leaves' pivots), but power is transmitted by a fairly complex system of shafts and gears. The articles referred to it throughout as a lifting bridge, but it was a swing bridge, with some some form of lifting assistance.
The reduced resolution image above, from Engineering 1887/10/28 shows aspects of the arrangement, and indicates the large number of spur, bevel, and worm and wheel gears, shafts and dog clutches. Unfortunately the drawings and the text leave many questions unanswered about the pivots, wheels, jacks, interlocks, etc. The drawing at bottom left shows a tunnel under the canal serving the water supply, which is evidently taken from the tanks on top of the castle turret.