Precast walls are one of the many new ways of constructing concrete retaining walls. In some instances, they cost less, take less time to build, and cause less traffic disruption than traditional cast-in-place walls.
Crib walls are assembled like a log cabin. First, workers set precast logs called headers on the prepared subgrade at equal intervals, each perpendicular to the wall face. Then, they set two rows of precast logs called stretchers across the tops of the headers, each parallel with the wall face. The cellular spaces between the stretchers and headers are backfilled with gravel, sand, stone, or compacted earth.
Interlocking precast bins stacked on top of each other and filled with granular soil also retain earth. The granular fill and the bins act together as a gravity wall.
PRECAST T-SHAPED UNITS
The building block for this system is a T-shaped precast unit. The top of each T forms the face of the retaining wall, and the stem acts as a soil anchor.
STACKED BOTTOMLESS TROUGHS
In this system, the stretchers and headers of a crib wall are precast together as one piece. The resulting module looks like a trough with no bottom. Workers stack one module on top of another and then backfill them to create a composite gravity wall.
PRECAST COUNTERFORT WALL
This patented system consists of triangular counterforts and curved or flat facing panels. Workers first set the precast counterforts perpendicular to the wall face at equal intervals. Then they place the precast facing panels between the counterforts and backfill the panels and counterforts.
PRECAST PANELS WITH INTEGRAL COLUMNS
Concrete panels, each precast with a column at one end, are joined by tongue-and-groove connections. Workers also weld each column to a cast-in-place pier.