PRECAST CONCRETE RETAINING WALLS
MAXIWall Concept, Design and Performance
The concept for the MaxiWall by Evergreen gravity wall system, is to provide an earth retaining wall capable of supporting heavy static and live loads, while remaining efficient and cost effective to construct.
MaxiWall users benefit from Evergreen’s forty plus years of world-wide experience, designing and constructing gravity retaining walls through out Europe, North America, South Africa, Middle East, and Japan.
The sum of the above goals is MaxiWall, consisting of high strength precast concrete elements that are efficient to transport to the site, efficient to assemble onsite, and efficient to backfill using on-site materials. The MaxiWall design does meet AASHTO and AREMA design Codes.
Evergreen MAXI users benefit from a true international cooperation: developed in Switzerland, by a European-American educated engineer, actively working internationally and accumulating experiences worldwide. The original, now classical Evergreen MACRO planted walls have been successfully built in most European countries, since 1978 and ever since 1980 in US and Canada, Japan, and South Africa. The Evergreen MAXI wall design follows the AASHTO codes.
The special issues cover concrete reinforcing design using proven silo pressure principles. Evergreen MAXI was originally made for the heavy US Railways grade separation. Railway design and construction means very high live loads, typically seven times higher than highways. That is where the much higher quality requirements come from.
For the concepts and details MAXI kept the pre-caster and the contractor in mind: build a wall system that works superb: easy for production, for transport, and for erection by benefitting from in 40 years of design and construction experience of an international team with the newest professional and practical know how: The MAXI wall system worked out perfectly for ten years now.
On-Site Materials are great for MAXI walls
Evergreen wall designers have a long history and experience for the successful use of on-site materials for earthwork, filling, and for backfilling. Why? Because clean sand and gravel often require foreign imports, which means high cost and sometimes even delivery shortages for large quantities. For that reason, MSE walls are rarely built in areas with silty on site materials only.
Obviously on-site materials require well compact-able materials, essentially with a water content near optimum to achieve the specified compaction density; (overly wet or far too dry materials are not compact-able and therefore not fit for backfill use.)
On-site materials for MAXI walls require drainage, such as an 8, to 12-inch drainage layer directly behind the font face to prevent any frost issues and of course drainage along the top of wall, along the heal of the wall as well as along the excavation face along a hillside to prevent any water pressure buildup.
Originally Evergreen walls were built mainly along cut slopes – they still are – yet MAXI found great applications for grade separations of rails, and highways as well as bridge abutment for its speed and ease of construction.