The Interstate Highway System, which celebrated its 50th anniversary in 2006, has used mechanically stabilized earth (MSE) techniques for approximately 34 years. Mechanically stabilized earth (MSE) is a construction technique that alternates layers of compacted soil and reinforcing elements to build retaining walls and embankments.  MSE walls are accepted by most transportation departments as a standard retaining wall for fill or for embankment support; however, this acceptance came only after research was developed that persuaded decision makers to take on the “new” technique.  As a result of research conducted by TRB’s National Cooperative Highway Research Program and the U.S Federal Highway Administration, along with efforts by the American Association of State Highway and Transportation Officials, the construction of MSE walls has become easier, faster, and more economical, particularly for fill projects, because the backfill material sometimes is available onsite.  In addition, MSE walls can be built quickly from prefabricated materials such as precast concrete panels or modular blocks.  The construction of MSE walls generally costs 30 to 50 percent less than that of cantilever cast-in-place concrete (CIP) walls, depending on the wall height.  The current estimated annual cost savings from the construction of MSE walls instead of CIP walls on the Interstate system is $180 million.

    
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