What is Culvert Lining?
Culvert lining, a trenchless culvert pipe rehabilitation method, allows culverts to be restored instead of replaced. Culvert lining eliminates the traffic disruption, increased cost, and permitting difficulty that comes with conventional replacement. There are a few different methods of culvert lining including slip lining with InfraSteel, a smooth wall carbon steel liner.
Hydraulic engineers struggle with the concept of culvert lining because the process shrinks the inside diameter of the existing culvert. Improved inlet devices improve the flow characteristics and often remedy that problem.
First, what is a culvert?
Why do culverts fail?
What does culvert lining prevent?
Culvert lining (and other repair methods) or replacement?
The extent of damage and distress to the structural integrity of the culvert
Effect on traveling public
The relative cost of either method
Availability of funding
Estimation of the remaining life-use of the existing culvert
Needed flow capacity
Culvert lining methods
1. Culvert Slip Lining – Slip lining involves installing a new liner or pipe inside of the old culvert. Culvert slip lining solutions are designed to pass through the tightest obstructions and shape change locations, providing the maximum flow capacity. The space between the liner and the old culvert is normally filled with grout, slurry cement, or similar flowable fill material. The liner is braced to support the structure to reduce the possibility of displacement or distortion.
- InfraSteel – A smooth wall carbon steel liner with a design life calculated to meet the owners requirements, provides increased structural integrity, and maximized flow capacity, with low environmental impact. Each liner is designed to match the shape of the existing structure.
- HDPE – A round, smooth–wall high-density polyethylene with a design life of 75 years, moderate increased structural integrity, low environmental impact, ideal when host pipe is also round.
- Round Smooth Wall Steel Pipe – Increased structural integrity, low community disruption, ideal for round culverts. Round slip liners can reduce the flow capacity in arched, elliptical, or box culverts.
- RCP – A reinforced concrete pipe with a design life of 50 years, high increased structural integrity, and low environmental impact.
2. Culvert Spray Lining – Spray lining is when the structure of the culvert is sprayed with a variety of different liquid products. Culvert spray lining typically is not going to provide the structural support of slip lining. Some spray lining materials include polyurethane and cementitious materials.
3. Culvert CIPP (Cured-in-place pipe lining) – Flexible, resin-saturated tubes are pulled into existing pipes, expanded with water or air pressure, and exposed to heat or ultraviolet light to stiffen. Curing takes five to 30 hours, depending on diameter.
4. CMP Plate Liner – A corrugated metal (CMP) plate liner provides corrugations extending through the lapped longitudinal joint. When assembled, this liner functions as a corrugated pipe with continuous circumferential corrugations.
5. Culvert Replacement – Total replacement of the culvert is usually extreme in community disruption, environmental impact, high costs to the traveling public, and permitting difficulty and is only used in areas where disruption is kept to a minimum.
Fill out the free culvert rehab products evaluation spreadsheet to find the product that is best needed. Set your project priorities and then fill in the data, viewing the results of what solution best suits you.
Temporary culvert rehabilitation methods
- Reinforced Concrete Invert – Sometimes, the damage to a culvert is limited to the invert. If the remainder of the culvert in is good shape, then the rest can be salvaged by adding a new invert through the installation of a reinforced concrete invert pavement section.
- Spot Patch and Repair – Small local repairs can be made to the culvert wall, or steel plates in the invert, and coatings using spot patching. The section of damaged culvert is cleaned, repaired, and then coated or painted.
- Repair/Modification to Culvert End Treatment – This may take the form of a reinforced concrete cut-off wall combined with slope collars or slope paving to restore integrity to the fill slopes at the culvert ends.
- Internal Bands to Problem Joints – Joint problems can be addressed using an internal band with gaskets and sealing materials that help restore uniformity of flow across the joints. Also sealing the area against significant infiltration and exfiltration.
- Shotcrete or Gunnite Lining – Cement plaster or concrete is applied using compressed air on the surface of the culvert wall. Reinforcement can be added to improve the strength and durability of such a lining.
- Sandblast & Repaint or Recoat – Rust, corrosion, or similar coating damage is removed and the wall is restored where the damage is superficial. The same material the culvert is made of will be used again.
- Stabilize Fill or Fill Isolated Voids – Using controlled injections or pressure grouting, distortion or overstress to the culvert can be avoided.
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