The Spit Bridge is a bascule bridge (Wikipedia: a moveable bridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic. Bascule is a French term for seesaw and balance, and bascule bridges operate along the same principle. They are the most common type of movable bridge in existence because they open quickly and require relatively little energy to operate.)
It is a major traffic congester on Sydney's north side.
Sydney's silly Sally saw Sam seeking some salmon!
ReplyDeleteI have serious doubts that the Spit Bridge is a 'bascule' bridge.
ReplyDeleteThe segment that rises is a lightweight mesh frame. On either side near the control tower are large cogs that occupy about 90°, to accommodate the angle that the span* travels through.
*on the far right, just appearing in the picture.
I imagine that it is a powered lifting span, there being little room for counterweights to swing down and under. Any lever-arm would be minimal.
PhredE