Little Sandy Bridges on I-79: anti-icing overlay installation
Thanks to the West Virginia Department of Highways and their contractors, on Friday morning I was able to get a close-up look at the Poly-Carb Flexogrid
anti-icing overlay being installed on the Little Sandy Bridges on I-79 near Elkview. Much like the Carter/Fort Hill/Oakwood bridge on I-64 in Charleston, the Little Sandy Bridges' curved configuration on a 70mph stretch of highway makes it another notorious hotspot for ice-related car accidents in the winter. I have been following the project at Little Sandy with interest, as this may have potential for reducing crashes at other high-risk locations in the area.
The Little Sandy site
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The Little Sandy Bridges near Elkview (use the Google map above to pan and zoom) carry Interstate 79 across the Little Sandy Creek valley on twin spans, about 2 miles south of the Elkview exit. The bridges are long, curved and banked - and the speed limit on the Interstate here is 70 MPH. As a result, when the Little Sandy Bridges become icy in the winter, accidents are a near certainty. Many serious ice-related pileups have occured at this site over the years. In fact, the accident rate at Little Sandy may be on par with the Carter/Fort Hill/Oakwood bridge in Charleston - but due to the remote rural location and lack of safe parking and accessability, I have not tried to document any crashes here.
The WVDOH has chosen the Little Sandy Bridges as one of several testing sites in the state for the application of the overlay system.
Anti-icing overlay
The overlay is simply an epoxy sealant applied to the bridge surface, which is then covered with a layer of crushed stone aggregate. The epoxy acts as a 'glue' in which the stone adheres to, creating a durable road surface that can stand up to normal highway traffic. The main function of the overlay is that the rough, porous nature of the stone layer along with the epoxy seal can hold in salt or brine applied to the bridge deck, preventing it from being washed away by precipitation or mechanically removed by traffic wear. The result is that a single application of salt or brine can last through several snow/ice events, preventing ice from forming on the bridge.
Furthermore, the overlay results in a rougher road surface, increasing overall traction for vehicle tires. The one drawback of this, as one of the workers told me, is you don't want to wreck your motorcycle on a bridge with this overlay installed!
Overlay installation at Little Sandy
I stopped by the Little Sandy site just as contractors were about to begin installing the Poly-Carb Flexogrid overlay on the southbound bridge. Preparation work included sandblasting (completed the day before) and pressure-cleaning the old road surface. The rig used to apply the epoxy and stone was put into position:
The epoxy was applied and spread over the bridge deck (the workers wear spiked shoes to avoid getting stuck):
Once the epoxy is down, a spreader lays down the stone aggregate:
Workers fill in any thin spots in the stone layer:
The process continues:
Shots of the completed overlay:
Disclaimer: This web site is not affiliated in any way with The West Virginia Department of Highways, their contractors, or with Poly-Carb Flexogrid .
