DJ&A was hired by the Confederated Salish & Kootenai Tribes (CSKT) to de-sign a replacement bridge over the Jocko River in Lake County. The existing single-lane bridge on South Valley Creek Road will be replaced with a double-lane steel plate girder bridge with composite concrete deck on steel piling. DJ&A analyzed and reviewed bridge and roadway alternatives, provided a hydraulic analysis, designed the re-alignment of the roadway approaches, and performed final structural design calculations for the bridge components.
Key elements of the design included increasing the bridge span to provide for adequate freeboard over the 100-year flood elevation and reestablish floodplain areas under the bridge. The horizontal and vertical alignments of South Valley Creek Road were designed as part of the bridge replacement to improve sight distance and meet AASHTO standards. DJ&A prepared the final construction plans, specifications and cost estimates for the construction bid package. In addition to engineering services, DJ&A completed the site survey, topographic mapping, and right of way surveys.