When you and your firm develop a retaining wall, it isn’t just about preventing soil or earth from moving. Your job is to protect the areas around the wall, which often include busy roads, businesses, and subdivisions.
The client expects a durable wall that will hold up under the elements and effectively retain soil under duress.
If a retaining wall structure loses its integrity or fails, lives could be at risk. At the very least, your company’s reputation will hang in the balance.
The safety and well-being of others and your company’s success all hinge on the reliability of your retaining wall.
There are a variety of considerations that all commercial retaining wall designers should keep in mind. Below are some steps for how to design a retaining wall, a few design considerations and ideas, and common causes of retaining wall failure.
Steps for Designing a Reliable Retaining Wall
1). Decide Wall Type
You will decide on a type of retaining wall based on its intended purpose and the environmental conditions where you are building.
For instance, you may need to install a nearly vertical slope to protect the elements on both sides, at which point you would utilize a gravity retaining wall.
Or, if you have more space, you would develop a tiered retaining wall or mechanically stabilized earth (MSE) wall.
2). Determine Retaining Wall Location
The purpose of your retaining wall and the available space will determine the exact location of your wall.
Designers must consider other goals when deciding on a location: reducing soil excavation requirements and optimizing existing grading, drainage, and site features.
3). Calculate Wall Height and Other Specifications
One essential step for building a retaining wall is determining the wall height.
The height of your wall will depend on both the vertical and horizontal distance between the two sections you are trying to separate and the type of wall you are implementing. Different retaining wall types work well at different heights.
For instance, cantilever retaining walls, which are the most common retaining wall, are economical up to a height of 10 meters. Designers calculate a wall’s base width, base thickness, and stem thickness based on the wall height.
While you should consult with an experienced engineer for your specific retaining wall project, these are some general formulas:
- Base Width: approximately ½ of the wall height
- Base Thickness: at least one foot and not less than ⅛ of the wall height
4). Determine All Structural Requirements
Once you have determined your wall height and location, the next step is to determine all structural requirements. You must also consider the wall materials you will use on your project.
For small retaining walls, developers may use stacked stone or natural stone. Due to their visual appeal, stone retainer walls are perfect for garden beds and other small residential outdoor spaces.
However, you will employ wall materials like concrete or granular infills for most commercial projects.
Concrete retaining walls are more economical and provide the structural integrity to withstand significant earth pressure, even during weather events.
Retaining Wall Design Considerations
Select the Right Wall Type
It sounds simple, but this is a step that many project managers don’t put enough resources into. The environmental conditions you are trying to control will influence the type of wall you choose, but that doesn’t mean you won’t have several options.
For large-scale commercial projects, involving engineers and foundational specialists is a quality investment that will impact your project’s lifespan and ability to withstand influxes of pressure.
Conduct Thorough Soil Tests
A crucial step for large-scale commercial retaining walls is to conduct thorough tests of the soils and materials around the wall. Gravity will constantly push down on your wall, but hydrostatic pressure will also come in waves.
You must know the earth pressure that the surrounding soil will apply to your wall both during normal circumstances and during heavy rains.
Develop a Reliable Foundation
Once you have a thorough understanding of the soil and environmental conditions, you can begin choosing a retaining wall foundation. As with every other consideration, the type of wall and available space will influence your foundation choice.
Some standard retaining wall foundations for maximum bearing pressures include:
- HDPE geogrids with infill
- Concrete Slab
Choose the Appropriate Materials
You should decide what materials to use on your retaining wall based on various factors, such as the conditions, project goal, budget, and available resources.
Depending on your wall type, you might work with concrete as your primary material, or you may have to select a base, supporting materials, and appropriate infill.
Keep Drainage at the Forefront
A retaining wall that does not provide adequate drainage will fail. When designing a wall, determining how water will drain around and through the retained soil needs to be one of the most important considerations.
Depending on your wall type, you can utilize designated water features, like a drainage pipe, or allow for flow-through granular infill material.
Free-flowing, fine infill is much more economical for drainage, but many walls require concrete and other materials. These wall types utilize designated drainage channels.
Remember Impacts on Surrounding Environment
One consideration that can be easy to forget is your retaining wall’s impact on the surrounding environment and vice versa.
For instance, let’s say that you are developing a retaining wall to protect a roadway. Adjacent to the bottom of your wall is a right-of-way that utility companies and the locality will disturb frequently.
You need to design your wall to handle those extra pressures.
Ensuring the Integrity of Retaining Wall Projects
You may feel pressure from your company executives or clients to cut corners to reduce costs.
When designing and constructing retaining walls, every minor detail matters. You must invest the time, thought, expertise, and resources into your project’s design and construction phases.
Below are some of the most common design or construction flaws that lead to the failure of retaining walls:
- Insufficient base width. Any wall with a base width less than half the total wall height will likely fail.
- Inappropriate infill materials and placement of backfill. Both the materials you choose and how you fill them impact a wall’s integrity.
- Inadequate drainage. If you don’t design a retaining wall with drainage in mind, water buildups and flows will cause your wall to fail.
The easiest way to prevent these problems is to devote significant time and resources to the design phase. Although it can be expensive, it is wise to have specialized engineers consult on large-scale commercial retaining walls.
The retaining wall experts at BaseCore stand ready to consult on your project.
BaseCore for Long-Lasting and Economical Retaining Walls
Developers have a lot to consider when designing commercial retaining walls, and there is simply no room to make mistakes. Any attempt to cut corners could prove fatal at the worst. At the least, it will harm your career and your company’s reputation.
You need to design every layer and component properly to ensure that the wall can withstand pressure for years to come. As you consider inexpensive retaining wall ideas, remember that the wall’s structural integrity is more important than the end cost.
We believe that geocell foundations are durable foundations that save companies like yours time and money.
Even on large-scale commercial projects and in soft-soil environments, they provide slope support that will last 75+ years and naturally resist erosion, corrosion, and other weather impacts.
Consult with one of our retaining wall experts to obtain product specifications and testing. We would be glad to answer any questions you have about geocell solutions.
Call us at (888)-511-1553 to learn more about the ideal retaining wall solution.