Big R recently partnered on a Design-Build project on an entrance road arch bridge solution for the Department of Veterans Affairs / State Construction Office in Swannanoa, NC. The project presented several unique challenges for our Engineering Department.
Road elevation required a lower foundation
A low road elevation was already set and, with the creek skewed to the roadway, a minimum 48′ span had to be only 6′ above the creek, so it wouldn’t interfere with the natural floodplain (as designated by the Engineer of Record). Our low-riding Super•Cor Box Culvert with steel reinforcement ribs was a natural fit. Plus, it had the strength to carry heavy loads with only a 2.36′ cover depth.
Saving time and money with Super•Cor
Geotechnical reports indicated poor foundation soils. The differential settlement criteria of the Super•Cor Box allowed it to be placed on cost-effective spread footings instead of the 70′ friction pile system that would be required by a 48′ span concrete arch bridge solution.
The setting required the top of the footings to be placed below the creek invert, so a layer of sheet pile was driven 20′ into the existing ground along the front edge of the footings. This was done as an additional protection to prevent sloughing and potential scour issues, since no prior Scour Analysis was performed.
It is estimated that Big R’s Super•Cor Box Culvert solution saved $300,000 to $400,000 over an equivalent concrete arch system.