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Winslow Wharf Marina - Bainbridge Island, Washington

The goal of this project was to replace a deteriorating wood marina that was constructed in the 1970’s. The new 235-slip marina, located on Bainbridge Island, was constructed in two phases to accommodate on-going use and occupancy of the marina during the construction process. 

Sitts & Hill provided structural design services for the pier extension and floating dock system, including design of a floating wave attenuation system.  We assisted with the City of Bainbridge Island in the permitting process, including several meetings with building officials to resolve questions about the proposed dock system.

The design presented a challenge due to a limitation on the number of piles allowed, which was established by the previously obtained environmental permits.  The final design incorporated innovated design methodologies to allow the floating dock to be constructed with the limited number of piles approved by the environmental permits.  This allowed the project to proceed without the potential delay associated with resubmitting the environmental permitting documents to request additional piles for review, a process which can take up to a year.

During construction, Sitts & Hill performed structural observations during the pile driving process, both to satisfy observation/monitoring requirements by the City of Bainbridge Island, but also to ensure that the piles as installed met the embedment and strength requirements of the design.  Varying soil conditions which impacted pile driving were encountered by the Contractor during installation, which required re-evaluation of the pile designs.  Sitts & Hill provided modifications to the original pile installation criteria to fit the actual conditions that were encountered, which allowed pile installation to continue without delay.