As an asset manager or engineer, it is your responsibility to look for structural rehabilitation solutions that truly repair the damage, not simply cover it up. At Sprayroq, we provide a solution for rehabilitation that is truly structural, strengthening your assets for decades to come.
Just how tough does a structural rehabilitation lining system need to be? It depends upon several factors to hold up under partially or fully deteriorated structures. In this post, you'll read about an amazing SprayWall® story of an insane level of lining thickness applied to an underground structure.
It is important to keep in mind that the lining thickness used for this particular project is not a required standard. However, it highlights the unique high-build qualities of SprayWall® to restore a structure under tremendous loads, one of the core competencies that sets us apart as a truly structural solution to underground asset rehabilitation.
When important assets begin to show signs of damage or corrosion, you are faced with decisions regarding replacement or rehabilitation. Completely replacing underground assets is not only an expensive endeavor but also results in lengthy periods of downtime. Fortunately, SprayWall® provides an excellent long-term, corrosion and chemical resistant solution, a lining system that not only measures up to structural standards but also meets with ANSI 61 standard for potable water applications.
SprayWall® dries quickly, enabling us to build liner thickness and complete the job on time. Because of this, you can get your assets back in service without the costly expense of traffic disruption by having to completely replace the underground infrastructure.
Because SprayWall® is a truly structural solution for asset rehabilitation, you will not be faced with the need to repeat the process in 8 to 10 years. SprayWall® offers an incredible return-on-investment due to its long-term strength and durability.
After more than three decades on the market, SprayWall® has been used in a wide variety of settings to repair underground infrastructure in all conditions. Since 1990, it has been used to rehabilitate over one million structures. Over 60% of those assets have required structural repairs, with the remaining 40% requiring only a corrosion-preventative thickness.
This particular project was an excellent demonstration of the strength and structural abilities of the SprayWall® polyurethane lining system.
Structural research and testing reveal that SprayWall® Polyurethane Structural Lining System meets the highest criteria for rehabilitating Corrugated Metal pipe (CMP).
Hamilton, Ontario is a port city approximately 36 miles southwest of Toronto. It is located on the southwestern tip of Lake Ontario with a population of over 550,000. Due to its location on Lake Ontario, Hamilton serves as a critical link in the Ontario maritime area with products such as fertilizer, aggregates, salt and steel making up most of the 700,000 metric tons that are shipped through the port annually. One of the key areas of the port is an area called Pier 12.
The Hamilton Port Authority was performing routine maintenance in 2016 when numerous infrastructure assets were noted to need direct replacement or rehabilitation. The Authority was able to secure funding for a three-year program to address the degraded infrastructure.
One specific asset in need of rehabilitation was a wet well located on the Pier 12 footprint that was installed in 1981. When it was installed, the steel vessel was 6 mm (0.237”) thick. When it was surveyed in 2016, the wet well showed severe corrosion that would require replacement to ensure a long-term return to service.
Replacing the 6.5 M (21.4’) by 3 M (9.9’) steel vessel offered up several technical and practical challenges. The Pier 12 wet well was located in a high-water table area that had an unstable geotechnical soil condition. Cofferdams would be required for the steel vessel to be replaced. However, existing underground utilities, as well as a limited budget, made this option extremely challenging.
Realizing the need for a better solution, AECOM, the Engineer-of-Record for the Port Authority, began to search for a more appropriate alternative. Enter SprayWall®, a rehabilitation technique utilizing a spray-applied structural polyurethane.
The SprayWall® technology is a spray-applied 100 percent VOC-free polyurethane coating that provides both structural and chemical resistance from the wastewater environment with the design thickness being determined utilizing a 50-year design protocol.
SprayWall® was an excellent candidate for this structural rehabilitation project as it would minimize the impact on the surrounding area and other underground utilities. This cost-effective solution would also have a significantly shorter construction time, therefore saving on bypass pumping costs.
Due to the deteriorated condition of the asset, SprayWall® was quickly identified as the preferred rehabilitation solution. Because of the high hydrostatic conditions and the poor geotechnical conditions, it was determined that SprayWall® would be applied to a thickness that would effectively create a new vessel.
Empipe Solutions, Ltd. of Hannon, Ontario, the local Sprayroq Certified Partner was eager to demonstrate the structural rehabilitation capabilities of SprayWall®.
First, a bypass system was established, allowing the team to evaluate the steel substrate and locate any thin areas that might need reinforcing before the substrate preparation process. The areas that were noted to be too thin were reinforced by welding on 250 mil (¼ inch) steel plates.
After the plates were attached in the thin areas, the steel substrate was shot blasted and power washed to attain a NACE No. 2 “Near White” profile. The shot blasting attained the 7-mil profile that was required to ensure quality adhesion for the SprayWall® to the steel substrate.
With the preparations complete, the design condition was agreed upon. Based on the vessel's poor condition, it was determined that a fully deteriorated design condition with a fully saturated groundwater condition was appropriate.
The extremely conservative design thickness for this project resulted in coating thicknesses that had never been applied before. This was due, in part, to the critical location of the asset.
For the main area of the structure, the thickness included was 1968.5 mils (50 mm), top to bottom. The top section, which is susceptible to live loads, was 4921.3 mils (125 mm). The base was designed to a thickness of 4409.5 mils (113 mm). A secondary bypass structure was built to 1968.5 mils (50 mm) on the walls and base while the top section was designed to 3464.57 mils (88 mm).
After preparing the wet well for application, the team of Sprayroq Certified Partners began the SprayWall® application process. Because SprayWall® is a thermally mass-dependent material, the team had to work carefully to achieve the desired exothermic rate. This is done by limiting the application thickness per pass, carefully adding layers until the design thickness is achieved.
To minimize the possibility of any challenges from temperature variations, Empipe elected to spray 24 hours a day, for six days. In this timeframe, they applied 14,600 pounds of SprayWall® completing the relining and meeting the stringent design requirements. The extreme conditions including heat, confined space, the volume of product applied, and high-build technique made the Pier 12 Wet Well project truly unique.
Upon completion of the rehabilitation project, the Pier 12 Wet Well was returned to service on time, on budget, and with minimal disruption to adjacent utilities. The SprayWall® structural liner is expected to add many decades to the operational lifetime of the Pier 12 wet well.
The Pier 12 Wet Well Rehabilitation is truly a testament to the strength, durability, and structural integrity of SprayWall®. By minimizing downtime, asset disruption, and cost, SprayWall® offers the best solution for structural rehabilitation of underground assets.