swing bridge 
noun
A bridge over water that can be rotated horizontally to allow ships through.The gem in the crown is the cable-stayed swing bridge over the Ouse itself....
- She said that for access to the site, the developers would be willing to provide either a fixed bridge or a swing bridge to replace the present bridge over the canal.
- The six-mile bypass, which is due to open later this year, will include a new swing bridge over the River Ouse as well as five other bridges and four roundabouts.