bascule-bridge

noun Civil Engineering.

1. a device operating like a balance or seesaw, especially an arrangement of a movable bridge (bascule bridge) by which the rising floor or section is counterbalanced by a weight.

noun

1. Also called: balance bridge, counterpoise bridge a bridge with a movable section hinged about a horizontal axis and counterbalanced by a weightCompare drawbridge
2. a movable roadway forming part of such a bridgeTower Bridge has two bascules