Concrete retaining walls are used in various locations to keep soil and other materials firmly in place. There are several different types of concrete retaining walls designed for various applications. A gravity retaining wall is thick at the bottom and narrow at the top while a counterfort wall is situated above and below the ground level. Cantilever concrete retaining walls have the same thickness from top to bottom and a very wide support footing. Buttressed walls are similar to the counterfort type but face in the opposite direction. Anchored retaining walls are mechanically supported by tethers.
Gravity concrete retaining walls are the most commonly used type and typically precast. This type of wall is usually no more than 4 feet (1.2 m) high and frequently utilized along roadways. Gravity retaining walls feature a thick base that angles upward to a narrow top. The angled side typically faces outward to prevent the structure from toppling over under a load. The thickness of this structure’s base is generally equal to one half of its height.
A counterfort retaining wall is a relatively economical option that is typically cast on site. This wall is triangular shaped and utilizes an additional subterranean footing for load support. Counterfort retaining walls are suitable for heights in excess of 25 feet (7.6 m). The overall design is similar to that of a cantilever wall, but generally less expensive to construct. The subterranean footing of a counterfort retaining wall typically provides superior resistance against bending.
Cantilevered retaining walls have the identical thickness from top to bottom. This wall variant utilizes a wide footing that extends toward the soil being retained. The footing relies upon the weight of the retained soil for wall stability and strength. Cantilevered walls generally require less concrete than other types and can be precast or constructed on site. These retaining walls are considered to be very strong and stable structures, but are usually quite costly.
Buttressed concrete retaining walls utilize a triangular design similar to counterfort walls. The basic difference between the two structures is the direction that the triangle faces. A buttressed wall faces outward from the retained soil to prevent it from tipping under heavy loads. Similar to the counterfort, this structure is also an economical retaining wall option.
Anchored retaining walls maintain a uniform thickness from top to bottom and require no additional support footing. This wall relies upon anchors embedded deep within the retained soil for support. The anchors are typically constructed of concrete or some type of expandable material. Tethers are attached from the anchor to the retaining wall to hold the structure in place. This design is generally unsuitable for loose or sandy soils.