Retaining structures are used where vertical drops create lateral earth pressure. Examples of these structures include gravity walls, cantilevered walls, and mechanically stabilized earth walls.

Retaining structures contain and support soil where loadings may otherwise cause the soil to move and impact the structure supported by it. Depending on the location and specifications, these structures may be concrete or altered soil. Refer to TxDOT’s for additional information on geotechnical design for retaining structures.

Selection of retaining structures will depend on factors such as ROW limitations, foundation soil characteristics, loading requirements, economic feasibility, and aesthetics. Whether the section is in cut or fill should also be considered, as some retaining structures are better suited for one or the other.

In situations where a roadway is elevated along a retaining wall, the drop off condition must be protected for the entire length of the wall, regardless of if the retaining wall is inside or outside the clear zone. Refer to TxDOT’s for additional information on protection requirements for a roadway elevated along a retaining wall.

A more detailed discussion on design calculations and geometric specifics can be found in the .