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Wildlife crossing’s staged construction keeps busy highway moving

November 30, 2012

Colorado-Wildlife-Crossing(web)A very busy US Highway 285 provides a vital commuter link between the foothills and metro Denver. As part of a highway improvement program, Big R Bridge was contracted to design and supply a new Wildlife Underpass at Shaffer’s Crossing at Conifer, CO. 

The Colorado Department of Transportation (CDOT) needed a safe and efficient plan to keep constant traffic flow in both directions during construction. Big R Bridge worked closely with the General Contractor to coordinate a two-stage construction schedule for our 144’ Bolt-A-Plate buried arch structure. Half of the structure is built and back filled with a temporary headwall, then the open lanes are moved on top of it so the other half can be built.    

Versatile Bolt-A-Plate does the job 

The hot-dip galvanized plate structure was shipped to the project site in nested bundles reducing the footprint needed to stockpile material in an already-tight location. To shorten assembly time, a keyway slot was cast into the concrete spread foundations to accept the corrugated steel plates. The keyway was later filled with non-shrink grout. This technique allowed the workers to erect the plates very quickly using a small crew and a readily-available, light-duty telescopic forklift. Lighter steel components eliminate the costly crane rental needed to construct similar-sized precast concrete structures.  


Collar bolts were placed around the arch periphery on both ends to accommodate the cast-in-place concrete collar end treatment. This provided an aesthetic transition to the modular block walls used on the project. After being backfilled, with compacted granular soil meeting our specifications, the headwalls were constructed and roadway work was completed.

Post-construction, the project received positive feedback and it showed the versatility of corrugated steel structures designed and fabricated by Big R Bridge.

Bolt-A-Plate, is just one of our many corrugated steel solutions able to meet the required 75 year service life.


Project Name: Shaffer’s Crossing
Location: Conifer, CO
Owner/Consultant: Colorado Department of Transportation
Contractor: Hudick Excavating
Type of Product/Application: Bolt-A-Plate/Wildlife Underpass/Drainage Structures
Dimensions: Bolt-A-Plate Wildlife Underpass (24' span x 12' rise x 144' long), Bolt-A-Plate Extensions (11' diameter)  
Installation time: 2 weeks for plate assembly

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