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Evergreen Point Floating Bridge

The Evergreen Point Floating Bridge carries State Route 520 across Lake Washington from Seattle to Bellevue. The bridge has a telescoping type draw span that opens at infrequent intervals to allow large ship traffic to the south end of the lake. The draw span is also opened in heavy winds to reduce the load on the bridge anchoring. The original bridge used a system of chains, pulleys and counterweights to lift the draw spans. Due to severe maintenance problems, it was decided to replace the original draw span lift system with a set of direct acting hydraulic cylinders. The motions of the cylinders are synchronized by a closed loop electro hydraulic position control system. While at Hamilton Engineering, Gil Lund was the Principal Engineer responsible for the conceptual design of the hydraulic span lift system for the bridge refit.

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