In which movable bridge do gantries at the piers lift the girder and floor system using hydraulic arrangements to allow ship passage, with the span rising vertically?

• A. Lift Bridges
• B. Bascule Bridges
• C. Swing Bridges
• D. Drawbridges

Answer: (A)

Movable bridges open ships by changing the vertical position of the span rather than swinging it aside. When the span rises vertically, it is attached to gantries at the piers and lifted as a unit using hydraulic or other lifting systems. This vertical lift creates the necessary clearance for tall ships to pass without tilting or rotating the deck.

That mechanism describes a lift bridge. Bascule bridges, in contrast, use hinged leaves that rotate upward, not rise as a unit. Swing bridges rotate the span around a central pivot, and drawbridge is a broader term often used for movable bridges that open by lifting or tilting, but the exact vertical lifting described points to a lift bridge.