Stormwater pipes and related assets are subject to wear and failure if not properly inspected and maintained. Stormwater pipes have an expected design life that is greatly influenced by the quality of the original installation and ongoing preventative maintenance. Regular inspections and preventative maintenance can help extend the life of the structure, prevent failures and reduce the public safety risk of dangerous sinkholes. Waiting until an issue shows up on the ground surface can be extremely costly when compared to regular maintenance cost and can be extremely dangerous for the public.
Centrifugally Cast Concrete Pipe (CCCP) or “Spin-Casting” and Robotic Shotcrete Concrete Pipe (RSCP) is used to structurally restore deteriorated CMP and RCP Pipes from 30” to 120” diameter (RSCP greater than 48” diameter). Both processes use the same material, and both provide a structural and cost-effective solution to deteriorated and failing pipes with no digging or traffic disruptions. There is no repaving or utilities to relocate. It can be used in most pipe shapes and in pipes with bends. The new pipe is 100% environmentally friendly, structurally sound and fully sealed from end to end without seams.
HOW THE PROCESS WORKS…….
The process begins with an inspection of the pipe to be restored. Based on depth, size and other factors, a thickness is determined for the application. Preparation work then begins. Flow through the pipe is diverted and gravel, mud, roots, and debris are removed. After this, the interior is thoroughly cleaned. In some cases, buckling, leaks, voids and damaged invert and joints will require repairs prior to installation of the CCCP or RSCP.
The high-speed spin-casting equipment or robotic shotcrete nozzle is secured to the retrieval sled in the center of the pipe at the opposite end of the pipe from the pump. As the high strength, fiber reinforced mortar is pumped and cast evenly around the interior of the pipe, the application equipment is retracted using a custom wench system at a set speed to insure an even application of the predetermined thickness.
Unlike other processes, the application equipment can be started and stopped as needed without joints or gaps. The only thing left behind is a seamless, high strength, fully structural pipe.
FAQ
How are cementitious liner thicknesses of 1” able to carry the load when pre-cast concrete pipes are several inches thick?
There are several reasons for the thickness of pre-cast concrete pipes that often have little to do with the insitu loading. Pre-cast concrete pipes contain 2-dimensional metal reinforcement that must be encapsulated by a specified thickness of concrete above and below the reinforcement. These pipes must also be designed to withstand shipping, handling and installation stresses. The desired manufactured length of pre-cast pipe sections also governs the thickness. Pre-cast concrete pipe in most circumstances is over designed for water, soil and traffic loading alone but must be manufactured at greater thicknesses to withstand shipping, handling and installation. Pre-cast concrete pipes rarely fail due to the insitu loading. However, they can fail as a system at the weakest area which are the pipe joints. (Note: We have repaired many sinkholes associated with RCP pipe joints. Our caged drone inspections can help identify these issues before they become a costly repair.)
Our high strength, 3D fiber reinforced cementitious liners are cast (installed) in place and only require enough thickness to carry the insitu loading from water, soil and traffic with a typical design factor of safety. Our liners are at a minimum twice the compressive strength used in typical pre-cast concrete pipe manufacturing. Because our liners are seamless, there is not a risk of a joint failure.
How do you verify the thickness?
Each pipe is carefully measured to calculate the quantity of material required. These calculations include variances for corrugation size and shape, installation variances and waste. In addition, the Nozzle Technician is constantly measuring the bead thickness at the nozzle. The Nozzle Technician may adjust the winch speed if needed to maintain a uniform bead thickness. A process control sheet is produced for each lined pipe and is available upon request by the Owner’s Representative.
How much does CCCP and RSCP cost?
Many factors may influence cost including mobilization, quantity, size, length, liner thickness, access, traffic, flow and cleaning requirements. A general rule for estimating the expected unit cost is $5.00 times the pipe diameter in inches (+/- 20%). Example: A 36” diameter CMP is ($5.00/in/ft x 36 “ = $180.00 per LF). With a +/-20% variance the expected cost would be $144 to $216 per LF for 36” diameter pipe. You can contact our office if you require an accurate budget estimate.
What is Robotic Shotcrete Concrete Pipe Lining (RSCP)?
Robotic Shotcrete Concrete Pipe Lining (RSCP) is like centrifugally cast pipe lining except that the lining material is applied using accelerated air to install instead of a high-speed centrifugal motor. Robotic Shotcrete Pipe Lining is designed for pipes 48” diameter and larger. Centrifugally Cast Concrete Pipe Lining (CCCP) on larger pipes can produce a liner that profiles the existing corrugations. The corrugated profiled liner produced from CCCP in larger pipes is an economical way to line the pipes because you are not using excess material to fill the corrugations. However, some customers chose to fill the corrugations to improve flow characteristic. The robotic shotcrete lining equipment can be used to help fill in corrugations on larger pipes. RSCP can also be used to line only the invert of the pipe. CCCP and RSCP can also be used together in certain applications.
What are the benefits of Centrifugally Cast and Robotic Shotcrete Linings over dig and replace methods or other trenchless repairs?
Centrifugally Cast/Robotic Shotcrete vs. dig and replace:
With CCCP and RSCP there is no digging in streets or around utilities, no asphalt removal and replacement, no removal of curb and gutters, no locates to call in, no utilities to relocate, no road closures or detours and no long inconveniences to homes, businesses and commuters. The cost to dig and replace can be 20%-100%+ more expensive than Centrifugally Cast or Robotic Shotcrete Linings.
Centrifugally Cast/Robotic Shotcrete vs. Cured-In-Place Liners (CIPP) and Slip lining:
There are no hazardous chemicals used in the CCCP and RSCP processes. CCCP and RSCP are typically less expensive than CIPP. CCCP and RSCP liners do not hinder aquatic wildlife migration. Slip lining may cause a significant reduction in flow and may require digging to install.
