The most important drawbridges in the world
Mobile bridges, commonly known as drawbridges, are impressive creations that attract the attention of the entire world. Its usefulness in our society is paramount, since they manage to communicate two areas of land without interrupting indeterminately the maritime or fluvial traffic. Thus, they have a double function. These bridges can be used both for ground transportation of pedestrians, cars and bicycles and for naval transport.
Those with the greatest history, the oldest ones, have the origin of their construction on a static or fixed bridge, simple bridges and without motorization, to which the mobile mechanism was later added. It is important to note that some small mobile bridges can be enabled without the need of an engine; a person can take care of its elevation and descent. However, bridges driven by electric motors are more common, whether they are operated with lathes, gears, pistons or hydraulics.
The type of bridges is not limited to the classification between fixed and mobile, but the latter can be of various kinds and, in addition, quite curious both in the way and in its mechanism of operation. Submersible, folding, vertical lifting, tilting and tilting, are some of the types of drawbridges…
The most impressive lift engineering works
- Pont Jacques Chaban-Delmas, France: It is a vertical lift or lift bridge. It has a mobile mechanism by which the central platform rises (75 meters in this case), allowing navigation through the Garonne River in Bordeaux.
- Tower Bridge of London: Built in 1894 on the River Thames, it is a swinging bridge. The articulated arms (tilting) weigh about a thousand tons, which can be lifted in less than five minutes thanks to its six accumulators of energy. It measures 244 meters long, 7 meters wide and 65 meters high. It is estimated that this bridge is trodden by more than 5 million people per year.
- Submersible bridge at the Corinth Canal, Greece: As its own name indicates, its main action is to submerge the central vain under water. It connects the Gulf of Corinth with the Saronic Gulf in the Aegean Sea, and can descend up to 8 meters. This bridge has a twin; there are two, one at each end of the isthmus. Its main advantage is that it does not present a height limitation for ship traffic.
- Bridge of Portugalete, Vizcaya: It is the first suspension bridge in the world with shuttle vehicle. A suspension bridge consists of a platform hung over cables and a board from which the cables and the platform are supported. The electric motor is responsible for moving the cables and the platform around the board. They are structures that are usually located at high altitude, 45 meters in this case.
- Gateshead Millennium Bridge, Newcastle: This bridge is the inclined type. As its name says, the structure leans on a longitudinal axis and rotates on that axis. The Gateshead Bridge is a pedestrian and cyclist bridge that spans the River Tyne. It connects Gateshead and Newcastle. Measures 126 meters in length and has a concave shape to leave a greater distance from the water.
- Scale Lane bridge in Hull, England: It is a rotating bridge, which rotates on its own axis. This black steel and pedestrian bridge has a robust character and curved shape. It proposes the pedestrian to cross the Hull River in a different way, on foot and enjoying the views, always keeping in mind the second function of the mobile bridges: to let the pedestrian or vehicle cross, from one side to the other without having to cut off the maritime traffic.
- Hörn Bridge, Germany: It is located in the Kiel Fjords. It has a length of 25.5 meters and is designed for pedestrian use. It is a folding bridge that has three joined platforms that shrink to form an ‘N’. The platforms are joined by hinges that function as a joint that stretches and shrinks the bridge platform.
- Erasmus Bridge of Rotterdam, The Netherlands: The Erasmus Bridge is 800 meters long but it does not rise entirely. It is classified as a tilting bridge. The movable part measures 89 meters long. It has an asymmetric pylon 139 meters high that gave it its nickname “the swan” for the similarity with the neck of this animal.
- Trinity Bridge, Saint Petersburg: This civil work measures 582 meters, it is the longest bridge in the city. It is also one of the most recognized symbols of St. Petersburg. It is a bascule bridge built in 1803 on the Neva River; it has more than 200 years of history.
- Thousand Islands Bridge, Canada: It is the smallest international bridge in the world. It links two countries (two islands), the United States and Canada. It measures 3.20 meters and is of drawbridge type, meaning it has an engine that allows elevating it like a wing.
In addition to having complex and impressive design and operation characteristics, the drawbridges solve what could be a great inconvenience for the traffic of goods from all points of the globe. This could not be possible without the advances in the engineering and construction sector.