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Harrison Bridge


This $12.6 million project included the replacement of a multi-span bridge on SH-97. The bridge is located in Kootenai County and is approximately 1-mile northeast of the City of Harrison.  The existing bridge was a combination pile trestle/steel truss, multi-span structure with a total length of about 508 feet.  In addition to crossing the Coeur d’Alene River, the site is bounded by water on all four quadrants adding complexity (Coeur d’Alene Lake, Thompson Lake, and Anderson Marsh and Slough).  The bridge sufficiency rating was a 6 based on a 100-point scale, and was load posted.  This posting required the school bus to unload children, drive across the bridge, have the children walk across and then get back on the bus.


The project design used an accelerated schedule.   A team approach on this project was used with Keller Associates leading project development, ITD Bridge Section providing bridge design, and ITD District 1 Materials section providing the geotechnical reports.  The new bridge was offset from the existing bridge, and constructed in stages to address construction traffic control.  Bridge design included a 4-span, 606-foot steel girder bridge over the Coeur d’Alene River.  Complex river and lake modeling was conducted to analyze flood evaluations.