Sliplining is a method of pipe repair that has been around for decades to repair structurally deficient pipe or add more service life to an existing pipe. Much of our nation’s infrastructure is greatly aging and in the Northeast, we have some of the oldest infrastructure including old galvanized metal pipe and old concrete/brick pipe that has been in the ground for ~ 50-100 years. It is a generally a trenchless method that involves the utilization of a smaller pipe slid inside of the defective host pipe to repair any structural integrity and/or infiltration of water and silts. Most times this involves checking that the structural and hydraulic properties of the smaller pipe is sufficient for the host pipe in question. Once the new pipe is inserted, bulkheads are built and the upstream and downstream end and then grout is injected into the annular space between the old and the new pipe.
Municipalities and clients will often research and select sliplining for their project because it checks several socioeconomic boxes. It is also a very cost effective method for pipe repair. Some of the reasons include but are not limited to:
1.) Speedier installations as a result of digging and replacing and traffic detours.
2.) Sliplining is a fraction of the cost to dig and replace the old pipe due to minimized excavation activities, lower impact to the traveling public, reducing or eliminating pavement work, and several other reasons.
3.) There is little to no traffic disturbance with sliplining as most of the culvert rehab work can occur off the shoulder of the road which allows the normal flow of traffic.
4.) Sliplining makes it generally easier on the permitting process due to reduced “in-stream” work. As culvert rehabilitation generally results in a faster project, it often allows the contractor to get out of the stream faster.
5.) Environmentally friendly. Often times aquatic life (fish, salamanders, etc) and sometimes even bats and other wildlife can have habitats within the culverts. The rehabilitation process often allows the host pipe to remain in place while the culvert gets fixed.
6.) Safer for the workers repairing the pipe as most of the work can usually be done off the shoulder of the road instead in the roadway. This allows the individuals to stay off the road and out of the way of the traveling public; greatly reducing their injury risk.
7.) Little to no disturbance to surrounding utilities as the culvert rehabilitation process reduces the amount of on-site digging. It is still important to identify surrounding utilities just in case other work is required; but often the nearby utilities will not be disturbed.
Generally speaking, the lifespan of a slipline design is meant to last for the design life of a given roadway or site design. The industry and the solutions aim for 50-100 year minimum lifespan design. This is a consideration that is always discussed during the vetting & design phase or during discussions with the project owner. It is important to note that design criteria such as: pH tolerance, abrasion levels, and resistivity of the soils and water, live load from traffic/rail/aircraft, and dead loads, amongst other design factors can affect the service life of any material.
All the pipe products represented by DLVEWS, Inc. are fully structural and can pass the high standards and requirements of even the most stringent highway requirements. All of the solutions are AASHTO and/or ASTM qualified. They do not rely on the condition of the host pipe or the surrounding grout for structural capacity and therefore can also be direct buried/standalone solutions. When owners, engineers, contractors, and developers work with they can feel confident that the best hydraulic and structural options have been offered to them.
What products does sliplining need? (Great to plug some products you sell)
In order to slipline a defective pipe, one must select a pipe liner of which there are several that DLVEWS, Inc represents including but not limited to:
Corrugated Aluminum and Aluminized Pipe
Tunnel Liner Plate
SPR-PE (Spirally Wound Steel Reinforced HDPE)
A bypass would need to be set up if there is active water that would disrupt normal sliplining activities. Normally smaller flows can be accommodated while lining with great ease.
Installers would then need to build bulkheads for which brick and mortar or just a high strength mortar is utilized. Skid rails and blocking would need to be established such that the liner pipe does not float or get damaged during installation and the grouting process. Grout is then injected into the annular space. Often times, we will recommend a low density cellular grout or lightweight cellular concrete (LDCC or LWC) be used as it is very pumpable, flowable, and presents a lot less buoyancy force on the liner. Other materials may be required to complete the lining process. Each site presents it’s own unique challenges. Do not hesitate to call DLVEWS to discuss your project.