Veterans Memorial Centennial Bridge
Location: East of Coeur d’Alene on Interstate 90.
History: The Bennett Bay Centennial Bridge was completed in 1991. It was part of a $20 million project to complete Interstate 90 east of Coeur d’Alene. In 1992, the Idaho Legislature renamed the bridge Veterans Memorial Centennial Bridge, as a fitting tribute to Idaho’s Military Veterans. The Bridge was designed by Howard Needles Tannem & Bergendoff (HNTB) of Bellevue, Washington. It has received numerous awards: Outstanding Civil Engineering Achievement, from the American Society of Civil Engineers; Concrete Bridge Award of Excellence, from the Portland Cement Association; and was a National Finalist, Engineering Excellence Awards, from the American Consulting Engineers Council.
Interesting points: Major repairs to the roadway slab are virtually impossible with this type of structure. Therefore, the design included several features to help the bridge endure climactic extremes over the years. Concrete is kept in compression by post-tensioning in all principal directions, a dense concrete overlay was provided for the riding surface, and all reinforcing bars in the top slab were epoxy-coated. This was the first bridge in the United States in which all post-tensioning strands in the top slab were encased in polyethylene ducts which will protect the strands from corrosion.
Statistics: The Idaho Transportation Department charged that the structure paralleling the shores of Lake Coeur d’Alene meet strict environmental design criteria to minimize negative visual impacts. The bridge is a segmental concrete box girder bridge, nearly 1/3 mile long (1730’). The four lanes of highway are carried 300 feet above the valley floor. Using the balanced cantilever method for the superstructure, the bridge was built from each of the three piers outward. Concrete was pumped to the top of each pier where crews poured each segment, until the roadway sections met, in perfect alignment. The Bridge was designed by Howard Needles Tannem & Bergendoff (HNTB) of Bellevue, Washington.