County Road 8 – Bridge over Fraser River

Fraser, CO

The Town of Fraser requested that Bowman investigate the possibility of a full bridge replacement at County Road 8 and the Fraser River, originally constructed in 1979. As a part of CDOT’s Off-System Bridge Inspection Program, the existing 38′ long bridge recently received a Sufficiency Rating of 46. This low sufficiency rating placed this structure in the “Structurally Deficient” category and in consideration for replacement. In addition, it qualified the proposed bridge for federal grant money through the Highway Bridge Replacement and Rehabilitation Program (HBRPP) Fund.

The existing structure had beams: (6) W 24×68 original girders and (3) W24x84 widening; deck: 4 ½” deep, 7 gage, orthotropic steel decking with approximately 10″ of bituminous pavement; and abutments: (3) 10″ H piles, (2) 8 3/8″ H piles and (4) 6 3/8″ x 7 7/8″ H piles with steel pile cap members consisting of (2) 6 12″x31/2″x3/8″ and 12″x3″x3/8″ steel channel cap at each abutment.

The proposed structure has a width of 47 feet, span of 46 feet, and utilizes Prestressed Precast Concrete (PPC) Deck Beams with a 6-inch cast-in-place concrete wearing surface, founded on bent pile abutments. In conjunction with the structural bridge type study and design, our civil engineers developed the bridge hydraulic report and scour analysis.