Culvert Repair Best Practices,

Specifications and Special Provisions

Best Practices Guidelines Bruce Wagener, PEEric Leagjeld, PE

Goals

• Provide guidance to MnDOT engineers in making better decisions on culvert repairs

• Provide guidelines, Special Provisions and Standard Details that will standardize practices and increase effectiveness and longevity of repairs

Focus

Trenchless rehabilitation or repair of CMP and RCP culverts from 24 to 72

inches in diameter

Outline

• Overview of rehabilitation, repair, and replacement

• Describe project tasks• Walk through the Guidelines

document• Special Provisions and Standard

Details prepared

Definitions• Trenchless: Repair or rehabilitation that does

not involve excavating the roadway

• Rehabilitation: The existing culvert pipe is returned to its initial condition or better

• Repair: A maintenance activity that keeps the existing culvert in a uniformly good safe condition

• Replace: Removal or abandonment of the existing culvert by open cut or trenchless methods

Project Tasks• Task A—Survey MnDOT, cities, counties, and

contractors• Task B—Survey of other state’s DOT’s• Task C—Research Synthesis: Literature review of

information provided in SP&R Work Plan, Tasks A and B, and other sources

• Task D—Best Practices Guidelines, Special Provisions, and Standard Details

• Task E—Feasibility Study: Recommendations for evaluating culvert rehabilitation and repair methods

• Best Practices Guidelines

• Special Provisions• Standard Details

Best Practices Guidelines

1. Introduction2. Culvert Repair Process3. Preparation for Rehabilitation or Repair4. Culvert Rehabilitation Methods5. Culvert Repair Methods6. Replacement using Open Cut7. Replacement using Trenchless Methods

2. Culvert Repair Process

• Identify the Problem• Determine the Cause(s) of Deterioration• Evaluate the Structural Condition• Evaluate the Hydraulic Condition• Evaluate Repair, Rehabilitation, and Replacement

Options• Implement the Design• Maintain the Repairs

Rigid vs. Flexible Pipes

• Rigid Pipe: Substantially self-supporting and relies on the surrounding soil for only a small fraction of its overall strength. (RCP)

• Flexible Pipe: Designed using soil structure interaction, where the majority of the pipe’s strength is derived from the quality of the backfill soils and compaction. (CMP, PVC, HDPE and fiberglass)

Repair, Rehabilitation, and Replacement Options

• Inspect• Repair• Rehabilitate• Replace

Repair and Rehabilitation Method Guidance

• Recommendations from suppliers, fabricators, or specialists

• HydInfra suggested repairs reports and flow charts

• FHWA Culvert Assessment and Decision-Making Procedures Manual

• FHWA Hydraulics Toolbox• Caltrans Supplement to FHWA Culvert Repair

Practices Manual

HydInfra Suggested Repair Methods

3. Preparation for Repair or Rehabilitation

• Environmental protection• Flow diversion• Infiltration control• Cleaning• Checking culvert clearance• Other preparatory work• Safety

4. Rehabilitation Methods

• Paved invert• Cured-in-place pipe liner (CIPP)• Sliplining• Centrifugally cast concrete mortar

liner• Spirally wound liners• Close-fit liners• Shotcrete

Paved Invert

• Use in CMP or RCP• Cast-in-place

concrete• Welded wire fabric

(WWF) or rebar reinforcing

• Anchored to existing culvert

Cured in Place• Felt tube saturated with resin• Pull in place or inverted• Polyester or vinyl ester resins• Epoxy resins for special

conditions• Generally not bonded to

culvert

Sliplining

Centrifugally Cast Liner

• Cementitious or other material applied by an electric or air-powered rotating head

• Usually applied to CMP• Thickness controlled

by speed that the machine is pulled through the culvert

• Cementitious mortars discussed in Guidelines

Spirally Wound Liners

Close Fit Liners

Shotcrete Liners

Placement of invert Completed liner

5. Repair methods

• Spall repair• Joint repair methods• Filling voids outside the culvert• Joint sealing with internal packers• CMP seam repair• Invert plating• Sprayed coatings and linings• Slab jacking• Compaction grouting

Spall Repair

• Repair spalls of concrete due to movement, freeze/thaw, structural distress, deicing materials, etc

• Personnel entry required• Similar to paved inverts

Joint Repair

• Fix infiltration and exfiltration at joints to prevent ground loss and surface settlement

• Infiltration can lead to culvert deformation if soil support is lost

• Guidelines discuss personnel entry joint repairs

• Remote repairs are also possible

Void Filling outside Culvert• Voids can develop due

to piping, joint infiltration, and invert erosion

• Special Provisions specify lightweight cellular or rigid foam hydrophobic urethane grout

Other Culvert Repair Methods

• Joint sealing with internal packers• CMP seam repair• Invert plating• Sprayed coatings• Slab jacking• Compaction grouting• Resetting and retying end sections

Other Important Features and Repairs

• Energy dissipators• Trash rack maintenance• Inlet and outlet protection• Aprons/cutoff walls

6. Replacement of Culvert Using Open Cut Methods

• Drainage Manual• Standard Specifications and Special

Provisions• Standard Plates• Other MnDOT manuals

7. Replacement of Culvert Using Trenchless Methods

• Conventional tunneling• Pipe jacking–Microtunneling– Auger boring

• Pipe ramming• Pipe bursting

Rehabilitation Special Provisions and Standard Details

Method Special Provision Name Standard Detail NamePaved invert Paving Culvert Invert 3X02 Paved Invert Repair - Corrugated Metal Pipe

3X03 Paved Invert Repair - Reinforced Concrete Pipe

Cured-in-place pipe (CIPP)

Cured-in-Place Pipe Lining 3X06 Cured-in-Place pipe Liner - Corrugated Metal Pipe3X07 Cured-in-Place Pipe Liner - Reinforced Concrete Pipe

Sliplining culvert pipe

Sliplining Culvert PipeGrout Culvert Liner

3X04 Sliplining Culvert - Corrugated Metal Pipe3X04A Sliplining Culvert - Corrugated Metal Pipe 3X05 Sliplining Culvert - Reinforced Concrete Pipe3X05A Sliplining Culvert - Reinforced Concrete Pipe

Centrifugally cast liner

Centrifugally Cast Culvert Lining

Repair Special Provisions and Standard Details

Method Special Provision Name Standard Detail Name

Spall repair Culvert Patching 3X03 Paved Invert Repair

Joint repair Repair Culvert Joint 3X01 Pipe Joint Sealing - Reinforced Concrete Pipe

Void filling outside the culvert

Filling Voids Outside of Culverts

3X08 Culvert Void filling Detail - CSP and RCP Culverts

Special Provisions and Standard Details

Available by request from:Lisa Sayler

MnDOT Bridge Office Hydraulics 3485 Hadley Ave

Oakdale, MN 55128 Phone: 651-366-4468

Email: lisa.sayler@state.mn.us

Questions?