What is a Retaining Wall?
Written by GJ Stott
Concrete Retaining Walls are structures designed to enable natural elements to resist breakdown. A retaining wall provides the structural support to hold the lateral pressure of the earth. For example a concrete retaining wall may help rock avoid erosion or keep soil from falling down a slope. Architects have created a number of types of concrete retaining walls including gravity, sheet piled, and cantilever retaining walls, all of which can have a variety of textures.
Types of Retaining Walls
AFTEC specializes in the building of precast retaining walls with architectural designs on the visible side of the wall. AFTEC’s precast industrial retaining walls are usually used to retain small to medium heights (up to 12 ft.) of earth from one level to another. We can also incorporate a precast fence wall on top where needed.
Gravity concrete retaining walls are constructed using large boulders or masses of precast concrete. These walls use the concrete wall weight to resist pressure from the opposing side. Short gravity concrete retaining walls use dry-stacked stone retainers with a batter, which enables the wall to lean back toward the retained element.
For larger needs, precast concrete, geosynthetics, gabions, crib walls or soil-nailed walls can be used for retaining. These walls are built taller and stronger by including reinforcement and rigid-footing applications. Fortification is often used internally and includes timber, soil, steel or polymer mesh reinforcement.
When block is used, such as building brick or block concrete walls, the structure is considered a masonry concrete retaining wall. Masonry retaining walls mean that masonry units (CMU block walls) are utilized to construct the wall. A masonry unit is generally a compressed earth block that is formed to be a specific size and weight. Using such units, a masonry wall can have equal resistance at all points on the structure.
Brick masonry concrete retaining walls use standard 8” x 4” x 2.25” size kiln-fired bricks and mortar. The main drawback from brick masonry walls is that brick has a short lifespan and absorbs large amounts of water.
Block masonry retaining walls are also built to a specified size and weight. Due to their congruence in nature and their large concrete block size, concrete block walls can be built faster than brick retaining walls. They are also often reinforced with steel to improve the lifespan of the retaining wall.
While generally the last option for concrete retaining walls, sheet piled walls are most effective for soft soils and extremely tight areas. Manufactured from steel, vinyl, fiberglass, plastic planks or wooden planks, sheet piled walls must be pounded at least two-thirds the height of the wall into the ground. Tall sheet piled walls need a tie-back anchor “dead-man” in the soil.
Cantilevered concrete retaining walls are made from steel-reinforced precast concrete or wet masonry. Using structural footing, these walls convert horizontal pressures from behind the wall to vertical pressures on the ground below.
Cantilever walls may be buttressed to improve their strength against pressure. These short wing walls are added at right angles to the main concrete retaining wall. Such walls need rigid concrete footing constructed beneath seasonal frost depth. Cantilevered retaining walls require much less material than gravity walls.
Regardless of the method used, the most important aspect of retaining walls is proper design and installation. The AFTEC Precast Concrete Retaining Wall ensures that pressure can be held behind its steel-reinforced three to eight-foot walls.
Precast Retaining Wall Materials
AFTEC industrial and commercial retaining walls consist of precast concrete panels and columns designed and engineered to withstand the lateral pressures of the earth to be retained. These walls are available with architectural finishes such as stone, brick, block, stucco or custom architectural designs on the visible side of the wall.
- Concrete: Aggregate, cement powder and water designed for the engineered mix desired. Steel reinforcement and concrete are the ultimate materials for building retaining walls.
- Concrete Blocks: Small rock aggregate, cement powder and water formed into a hollow block. The concrete blocks are then stacked on continuous concrete footings using grouted cells and reinforcing for structural strength. Labor intensive.
- Cinder Blocks: Volcanic aggregate, cement powder and water formed into a hollow block. The cinder blocks are then stacked on continuous concrete footings using grouted cells and reinforcing for structural strength. Labor intensive.
- Stone: Stone is sometimes used for retaining walls in areas where it is plentiful by slant stacking, using the specific gravity of the stone to retain earth.
- Brick: When used, brick is a fascia on retaining walls for appearance. Brick does
not have structural integrity for retaining capabilities.
- Stucco: Stucco is also used for an fascia appearance on retaining walls.
- Wood: Wood timbers or rail road ties are sometimes used for retaining walls, but unless properly treated, wood deteriorates when used as an earth retaining wall.
- Steel: Steel is used in all steel reinforced concrete retaining walls for structural strength.
Building a Retaining Wall
When a project is ready to commence, AFTEC sets the process into motion. First, the retaining wall design goes to engineering. While the wall is being engineered, our forming and mold shops compile the specialized concrete retaining wall forms used for producing the wall components. Once the engineering is complete and approved, the wall components go into production. The production of the components will usually be accomplished using AFTEC’s Forming Equipment by one of AFTEC’s Producers nearest the locality where the retaining wall will be installed.
The installation process starts with the laying out and excavation of the caisson footings. The caisson footings are then poured to the proper elevation with the structural columns embedded into the footings. On completion of the caisson footings, the panels are delivered and installed.
The cost of designing, furnishing and installing a retaining wall for a project is determined by many factors which include the following:
- Location of project
- Retaining height
- Length of wall
- Soil conditions
- Lateral loads
- Water drainage
- Backfill required
- Type of architectural finish
- Labor conditions
- Equipment availability
- Owner/Contractor requirements for jobsite
- Underlying obstacles, utilities etc.
- Overhead obstacles, utilities, bridges etc.
Give us a call at 866-370-3676 for an estimate.
Benefits of Precast Concrete Retaining Walls
- Aesthetic Appeal: We offer a wide variety of precast concrete retaining walls designed to suit any and every artistic taste. The retaining walls are easily stained to match other nearby landscaping, including tile, sculptures, and metalworking. AFTEC retaining walls are also available in many colors, designs, textures, and styles.
- Erosion Control: Erosion hinders more than just beaches and canyons; it
- damages lawns and gardens too. The most common types of landscape erosion come from two sources: water and people walking on the grass. Both are easily prevented when utilizing a precast concrete retaining wall.
- Flood Prevention: Those who live close to bodies of water understand the persistent threat of flooding that comes with a lakeside view. By placing retaining walls alongside property borders near water, you’re buying your landscape many more inches of safety before it gets flooded.
- Protecting Plant Life: Not only do retaining walls protect vegetation by warding off unwanted guests and preventing floods, but they also reduce plant life casualties incurred during lawn maintenance. AFTEC Concrete Fence Forming Systems also employ a Rigid Footing Support System that reduces how often concrete footings are needed in the landscape. Concrete footings, though helpful and necessary, can disrupt plant-based ecosystems when there are too many. AFTEC’s system reduces the sheer volume of concrete footings which, in turn, allows plant life to further thrive.
- Cost-Effective: The walls utilized by AFTEC Concrete Fence Forming Systems are cantilevered concrete walls that are among the most durable in th marketplace; some even meet the standards of hurricane resistance. The unique design of a cantilevered wall also maximizes durability while reducing the amount of material needed to make the wall. This creates a better product that is more affordable to the consumer and is more efficient to install.