The Slauerhoffbrug Drawbridge
The Slauerhoffbrug Drawbridge is a fully automatic bascule bridge in the city of Leeuwarden in the Netherlands. A bascule bridge, also known as a drawbridge, has a section of the bridge that swings up to allow the passage of boats. The Slauerhoffbrug bridge crosses the Harlingervaart. One of the main designers of the bridge is Emile Asari. The bridge can be quickly lowered and raised by one pylon instead of two hinges. This is the only bridge to actually move the road out of the way. The bridge is painted with the colors of the town’s flag–yellow and blue strips.
What holds the bridge are the beams that are at each side of the bridge but not in the middle because thats were boats pass. When the bridge is being lifted it is supported by the arm that lifts.
https://www.atlasobscura.com/places/slauerhoffbrug-flying-drawbridge