With structural engineering in our backgrounds, we’re crazy about bridges here at the BUILDblog. We’re also very lucky to have some incredible bridges right here in the neighborhood. The waterway connecting Lake Washington to the Puget Sound includes 7 bridges (8 if you include the walkway at the locks).  For today’s post we’re going to cover the five bridges that are dynamic in nature. What fascinates us most about these operable bridges is that they are designed, both structurally and functionally, in two completely different positions – horizontally and vertically. The engineering has to be worked out in two distinct, and possibly conflicting, scenarios.  Architecturally the structures change from a line on the horizon to a vertical mass the size of a small building. Imagine taking any piece of architecture, flipping it ninety degrees and having to reassess it all over again.

Salmon Bay Bridge,1914, 200 foot opening span, single-leaf bascule bridge

Ballard Bridge, 1917, 2,854 feet long, double-leaf bascule bridge

Fremont Bridge, 1917, 502 feet long, double-leaf bascule bridge

University Bridge, 1919, 218 foot opening span, double-leaf bascule bridge

Montlake Bridge, 1925, 344 feet long, double-leaf bascule bridge