[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.
In this part 2 of 2, various types of retaining walls are examined as possible alternatives in a side-hill retaining wall situation. These include conventional wall types such as CIP walls, MSE walls, gravity walls and soldier pile walls and some less conventional approaches such as lighweight concrete fill, hybrid soil-nail and geofoam wall systems, ground improvement and micropile walls.
Part 1 of this Side Hill Retaining Wall article covered the definition, significance, problems and failure modes, investigation techniques, analysis, and construction considerations of side hill walls. A PDF version is now available for download as well. Click through for the article and the download link!