Design Protocol Considerations

July 23, 2020
Structural Rehabilitation

As an engineer, there are many things you must take into consideration when it comes time to rehabilitate an asset using a spray-applied lining. Many thoughts and methodologies are being introduced to the market rapidly at this current time. Now, more than ever, it is critical to conduct your due diligence before you decide on a rehabilitation approach. At Sprayroq, we want to work alongside you to answer these important questions while providing you with valuable information as you work to protect your assets!

Spray-Applied Lining Design Considerations

There are a few structural design considerations you must keep in mind during the initial phases of your rehabilitation process.

What type of liner do you need?

What is the true condition of your structure currently?

How do you design for that condition?


Before beginning the project, we must also determine the level of protection that you require in order to determine the type of lining thickness is needed for the structure. Finally, we must choose between two structural design tracks or courses of action:

Partially Deteriorated Structural Design

Full Deteriorated Structural Design

Sound engineering principles and design standards are essential to successfully rehabilitating your structure. It is important to research the track record of the product and the design standard being utilized in conjunction with one another to find the best solution.

Determine the Level of Protection You Require

The first step to determining the level of protection you require is to consider your goal for rehabilitating the asset. What is your desired outcome? Does your project require corrosion protection only or both structural and corrosion protection? The answer to this question can be seen initially in whether or not active infiltration is present within the given structure.

‍The primary concern of engineering design in buried infrastructure is the influence of hydrostatic (groundwater), dead (soil) and live (active traffic) loads. These loads create stresses that act on the structures and must be accounted for in the proper design thicknesses to be applied. Failing to properly account for these variables before beginning your project will cost you time, money, and frustration.

With that in mind, there are 3 key components to evaluate in design protocol considerations which are as follows:

Corrosion Barrier only suitability is a standard corrosion barrier application with the ability to handle the current load on the given structure.

Assuming a Corrosion Barrier is not suitable, is a partially deteriorated structural design suitable for the current load on the given structure?

Assuming a Corrosion Barrier is not suitable, is a fully deteriorated structural design better suited for the current load on the given structure?

Let’s explore these 3 key components in greater detail. Learning more about the situations surrounding the three types of applications will allow you to evaluate the current condition of your structure. This provides you with valuable insight into your upcoming rehabilitation project.

Corrosion Barrier Application

A Corrosion Barrier application is typically 125 mils or 1/8-inch thickness. It is considered the standard minimum application thickness for most wastewater infrastructure applications. This is typically reserved for new structures or those with no active infiltration or seepage through the wall or current lining of the structure.

The Corrosion Barrier only application is fairly straightforward with no design required. However, there is evidence in the marketplace that this type of application is used incorrectly in many cases where a structural application should be utilized. Opting for a Corrosion Barrier only application in a situation that requires a different type of application could result in expedited damage.

Partially Deteriorated Structural Design

Partially Deteriorated Structural Design is considered when the structure can withstand dead (soil) and live (active traffic) loads and has no significant deflection. It is only influenced by the hydrostatic load (groundwater). This is evidenced by the observation of water within the structure either by seepage, infiltration, or inflow. If the wall of the structure is compromised by outside water force, you must be careful to use the proper design thickness when installing a liner.

Any structural lining you will install into a structure that has been compromised by water must have the ability to withstand the external pressure from the static water table force. This is the primary basis of the Partially Deteriorated design. Partially Deteriorated designs represent over 80% of structural designs with Sprayroq’s structural liner, SprayWall.

Fully Deteriorated Structural Design

In Fully Deteriorated Structural Design, the other loads, dead and live, are also assumed to influence the structure. The Engineer-of-Record observations may include things such as exposed rebar, missing pieces in the substrate, water infiltration, and soil exposure. A structure in this condition, in theory, is nearing collapse or complete failure.

In this case, we must add the dead and live loads to the hydrostatic load. Doing so will allow you to calculate the additional liner thickness. This effectively creates a “stand-alone” repair. When utilizing Fully Deteriorated design, the spray-applied polymer molds to fit the existing structure at the appropriate thickness. This new polymer structure is buried directly without requiring additional support from the existing, failing structure. Fully Deteriorated designs represent approximately 10% to 15% of structural designs with Sprayroq’s structural liner, SprayWall.

Sprayroq Structural Protective Lining Systems

Working With Sprayroq

Taking into account proper design protocol considerations helps both engineers and asset owners achieve their desired outcomes with an infrastructure rehabilitation project. By investing time upfront to conduct due diligence into design methodologies, you will have greater peace of mind once the project is complete.  

The axiom of “success by design” has been used in the business world for years. However, in the case of infrastructure rehabilitation, this is not just a lofty phrase to be thrown around. With the help of Sprayroq, “success by design” is tangible and well within your grasp.

SprayWall provides superior corrosion resistance while restoring the structural integrity of your infrastructure. With over one million applications, it has proven to be the longest-lasting polymeric solution in the industry. SprayWall is not only effective, but it is also incredibly efficient with the quickest return-to-service.

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