Uwall Retaining Wall for Material Hoppers Access

White Bros, Inc. successfully installed the first Uwall project in New England using geogrid reinforcing.

  • The 16' high retaining wall is part of an asphalt plant at Lane Construction's property in Westbrook, Maine.
  • There are two vertical walls, both 16' high with 35 degree wings.
  • The larger wall is 3,219 square feet while the second wall is 1,158 square feet.
  • The 8' x 4' units feature a split stone finish.


Installation was smooth and expeditious. The field crew was able to set 12 units per hour (396 sf/hour). The crew said the Uwall system was the fastest and easiest to install they had ever seen. Josh White, project superintendent for White Brothers, was very impressed with the look and ease of installation. "This is a great system, easy to install, very functional. I would definitely consider it for any wall in the future, without a doubt" he said.

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The wall will ultimately create a platform permitting trucks to back up to large material hoppers. For this reason, there could be no batter on the wall. The wall design incorporated the surcharge load from the trucks as well as the lateral earth loads. Maccaferri Macgrid TMWG8 was used for stabilization. One of the unique features of the Uwall is that no connection between the wall and the geogrid is required due to the keyed connection between the precast units. Every other grid layer is also locked in to the keyways for added stability.

The units are very easy to handle and erect. There are 2 utility anchors in the stems placed slightly behind the center of gravity. This causes the piece to hang with a slight pitch forward allowing the crew to easily align the face which is the first part to touch. A half inch pad is placed on the top edge of the face for bearing and alignment. Another small pad is placed in the keyway for leveling purposes. Filter fabric is placed behind the vertical joints to prevent fill from passing through. Backfill and compaction in 1' lifts proceeds after each course is set.

Not only do the erection crews like Uwall, so do the truck drivers. Uwall is very easy to load and unload. 11 pieces (352 sf) easily fit front to back on a flat bed. The weight of 11 pieces is about 23 tons and the width is 8 ft. They are easy to tie down with one strap each and trucking is a breeze.