ENR Reports that Pennsylvania Route 22/322 now has the longest MSE Wall in the U.S. and Canada, and the 2nd longest in the world. The project is located in Mifflin County, Pa. and involves adding an additional 2 lanes in a bifurcated alignment to supplement the existing 2 lanes in a dangerous stretch of roadway known as â€œLewiston Narrows,â€ between the Juniata River and Shade Mountain. The project also involves approximately 9,000 micropiles, 8,280 linear ft of shoreline retaining walls (nine), and approximately 40,000 ft of H-piles were driven for the retaining wall and for two bridges. (Photo by the Reinforced Earth Company)
[Correction] Whoops, I think it’s North America’s tallest MSE Wall, not the world’s. Anyone know what the World’s tallest MSE wall is? [/Correction]
TheNewsTribune.com has an interesting article on the Sea-Tac third runway project and how it is nearing completion and an overview of the hurdles faced. This was a unique project from a geotechnical perspective because in order to construct the runway, North America’s tallest MSE retaining wall at 130-ft high was built. One thing I didn’t know is that the 13 million cu-yd of fill needed to construct the runway needed to pass careful inspection to make sure it was free of contaminants and similar in mineralogical composition to the on-site materials. The implications and reasoning are explained in this quote from the article:
â€œWe had to find gravel that originated in the same place in Canada and that was transported here by the glaciers as the gravel that was here on the site,â€ said King.
The reasoning behind such a requirement is that water that leached through the fill would pick up minute traces of the minerals in the fill, drain into the creeks and confuse or damage native salmon returning to those creeks.
By way of ASCE SmartBrief.
TRB’s National Cooperative Highway Research Program (NCHRP) Report 663: Design of Roadside Barrier Systems Placed on MSE Retaining Walls explores a design procedure for roadside barrier systems mounted on the edge of a mechanically stabilized […]