On Friday, June 11th 2011, the Seattle Chapter took a tour of the Montlake Bridge (map) near the University of Washington campus. A bridge may not seem like it is very dependent upon mass properties or weight engineering, but the Montlake Bridge is a double-leaf bascule bridge. A bascule (a French term for seesaw) bridge is a moveable bridge with a counterweight that continuously balances the span, or “leaf,” throughout the entire swing which provides clearance for boats to pass through.
Our guide was Rick Rodda of the Washington State Department of Transportation (WDOT). We walked on and under the bridge and visit the control tower. During the tour, it was necessary to have the bridge open and close to let a boat thru the Montlake Cut. As such, we had the opportunity to see an opening and closing from below the bridge deck.