There is a neat little blurb in Roads and Bridges magazine on a small mechanically stabilized earth (MSE) retaining wall at NASA’s Wallops Flight Facility on the Coast of Virginia. The wall was designed and supplied by the Reinforced Earth Company (RECo) back in 2011. Although the wall is only 10 feet high supporting a bridge abutment, it is the route that the Antares Rockets take to reach the launch pad and eventually blast off to resupply the International Space Station. Design challenges for the wall included possible inundation with seawater, extreme live loading, and very thorough QA/QC by NASA and their designees. The live loads were 1,500 psf or about 6 times the normal highway live loading! Read more in Roads and Bridges Magazine.
[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.
This summer, the National Concrete Masonry Association (NCMA) will release the third edition of its Design Manual for Segmental Retaining Walls (DMSRW) along with SRWall 4.0 software for the design of segmental retaining walls. SRW walls with higher wall heights often make use of geotextile or geogrid reinforcement putting them in the category of mechanically stabilized earth retaining walls or MSE Walls. The first edition of the manual was published in 1993 and is routinely used for everything from landscaping walls to multi-tiered commercial and residential retaining walls. This summer is shaping up to be a busy one for those in the retaining wall business as the FHWA NHI 2009 MSE Wall Manual is set to be released around the same time frame as well. Read on for more info on the DMSRW. (Screen shot by Gabriela Mariscal from NCMA via CE News)