California Department of Transportation
 

DIB 83-02 - 8.1 Guidelines for Comparison of Alternative REhabilitation Techniques

DESIGN INFORMATION BULLETIN No. 83-02
CALTRANS SUPPLEMENT TO FHWA CULVERT REPAIR PRACTICES MANUAL

8.1 GUIDELINES FOR COMPARISON OF ALTERNATIVE REHABILITATION TECHNIQUES
  8.1.1 Table of Alternative Repair Techniques
  8.1.2 Process Flow Charts
         

8.1 Guidelines for Comparison of Alternative Rehabilitation Techniques

8.1.1 Table of Alternative Repair Techniques

Following problem identification, the Engineer must determine which of the multiple potential options for rehabilitation should be selected. There is no specific methodology

for making this determination, and in many cases several repair options will be viable. In all cases, the key element is to first understand the conditions leading to the failure/deterioration of the existing pipe. Unless there have been significant changes in the upstream watershed, these conditions will likely persist and the selected repair strategy must be able to effectively counteract these conditions.

The table on the following page(s) was developed as a general guide. Individual techniques, different fabricators, different chemical formulations, varying geotechnical conditions, condition of the host conduit, and installation techniques and procedures all are influential in the ultimate outcome of the repair technique. When designing and installing any of the various techniques, it is recommended that contact be made with suppliers, fabricators, or specialists to clearly ascertain the probability of success. Ultimately, only experience in varying situations and conditions will tell accurately what methods have the best potential for meeting the design objectives. Caltrans continues to evaluate most of the possible repair methods with the ultimate objective of developing design and installation specifications. Refer to Index 10.1 for a discussion on Caltrans New Product Approval process and Construction- Evaluated Experimental Feature Program

The following references provide some additional guidelines for comparison of alternative techniques:

FHWA Culvert Restoration Techniques Report No. FHWA/CA/TL-93-14, Part I (7) “Guidelines for Comparison of Alternative Techniques.”

FHWA Culvert Repair Practices Manual Volume 1, Chapter 6, pages 6-3 and 6-4 and Chapter 7, page 7-24.

Technique
and
Materials
Const.
Cost
Size
Range
Problem Resolution and Advantages Limitations

Sliplining with continuous or discreet pipe lengths

HDPE, PVC,
CSP, RCP, RPMP PRC, FRC

Med.

18 inches –
120 inches

Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.

Quick insertion; simple method requiring minimal investment in installation equipment and relatively little technical skill.
Multiple materials.
Provides a virtually new culvert comparable to replacement.
Continuous HDPE pipe has very few joints and is capable of accommodating large radius bends.
Large range of diameters can be repaired depending on material used.
Specialty liners are available in short lengths and constant O.D. (no bell or coupler)

Need fairly large area for liner insertion/jacking pit
Reduces cross section area because the annular space between the old and the new pipe must be grouted which may reduce hydraulic capacity.
May increase velocity of flow.
The environmental concern with this technique is the control of the low-density grout.
Labor intensive jointing for fusion welded HDPE
Difficult to reconnect laterals

HQ approval needed for plastic liners exceeding 60 inches

Fold and Form
PVC

Med. to High

< 15 inches

Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.

Smaller construction footprint than sliplining
Easy to transport and handle.
Viable technique for storm drains and culverts in non-abrasive urban settings.
No annular space grouting required.
Capacity maximized

PVC may become brittle in freezing temperatures.

Specialized equipment and trained personnel needed.

Very limited sizes; little or no use for most projects.
Cannot accommodate diameter variations and joint settlement.

Only circular shapes possible.

Cured in Place Pipe (CIPP)

Thermosetting resin-impregnated flexible fabric tube

High

12 inches - 96 inches

Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.

No annular space grouting required.
Very smooth interior surface may improve hydraulic- capacity. Capacity maximized.
Non-circular shapes can be accommodated.
No jacking pit required.
Eliminates pipe joints/seams and bridges all joints and irregularities on the interior surface of the host pipe.

Easy to transport and handle.

Good technique for storm drains; can access through MH or DI and can accommodate variations in cross section, minor pipe deformations and bends of up to 90 degrees.

Specialized equipment and trained personnel needed.

Site setup high proportion of cost on smaller projects.

Environmental concerns for disposal of waste water:
Water must be recaptured and trucked off site to a prearranged disposal site.

Groundwater infiltration may need to be controlled.

Lateral connections are easily handled but may require sealing after they have been cut.

HQ approval needed for CIPP exceeding 60 inches

External Grouting voids
(Index 6.1.2)

Low

All sizes

Voids behind culvert

Prevents further distortion or collapse of culvert by re-establishing soil-pipe interaction.

Difficult to judge completeness of repair

Crack Sealing (RCP)
Mortar/Epoxy

Low

> 36 inches

Cracks in RCP

Low resource commitment.
Protects reinforcing.

May be only a cosmetic repair if basic cause of the cracking is not determined and treated.
Requires human entry.

Invert Lining:

 
with PCC, or

 

CRSP, or

Steel plate

 


Med.

 

Med.

Med.

 


> 36 inches

 

> 72 inches

> 48 inches

Invert Repair for Concrete and Metal Pipe

High strength concrete and/or hard aggregate/or steel plate provides abrasion resistance.
Can easily modify thickness to meet needs.
Limited to bottom third of pipe
Simple method requiring minimal investment in installation equipment and relatively little technical skill. If invert perforation is present, same equipment can be used for invert paving.

Human entry only.
Cement is subject to break down if runoff is acidic and concrete mix design is not modified.
May be difficult to attach wire mesh reinforcement or provide mechanical tie to host pipe.
Ventilation needed for welding

Internal
Joint Sealing Steel Expansion Rings and rubber gaskets

Low

15 inches –
216 inches

Infiltration/Exfiltration at Joints

Low resource commitment.
Prevents further deterioration due to infiltration or exfiltration and loss of backfill.

More applicable to RCP than flexible pipe. If used on CMP or plastic, pipe must not be deflected beyond 10%.

Generally, pipe must be large enough for human entry.

Deform Re-form
HDPE

Med. to High

< 18 inches
(Larger diam. Being evaluated)

Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.

Smaller construction footprint than sliplining.
Easy to transport and handle.
Viable technique for storm drains and culverts.
No annular space grouting required.
Capacity maximized

May be difficult to reform larger diameters with thick walls.
Specialized equipment and trained personnel needed.
Only circular shapes possible. Cannot accommodate diameter variations and joint settlement.
Range of available pipe diameters is limited.

Machine Spiral Wound PVC

High

<108 inches

< 30 inches for radially expanded
method

Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.

Smaller construction footprint than sliplining and other methods because liner is formed on site and no pipe storage is necessary.
Easy to transport and handle.
Viable technique for storm drains and most culverts.
Can access through MH or DI
Annular space grouting not needed for radially expanded method.
Large range of diameters can be selected within the range of the winding machine.

May become brittle upon freezing.
Continuous interlocking joint system can be problematic if the host pipe diameter fluctuates.
Specialized equipment and trained personnel needed. 
Reduction in hydraulic capacity can be significant for smaller diameter host pipes.
Annular space grouting required for some spiral wound methods.
HQ approval needed for plastic liners exceeding 60 inches

Air placed concrete and Sprayed epoxy or polyurethane lining

High

N/A

Drainage Structure Rehabilitation

Will provide a corrosion barrier to reinforcing steel for concrete drainage inlets and manholes.

Limited to concrete drainage structures

Specialized equipment and trained personnel needed. 

Cement Mortar Lining

 

Cementitious mortar containing acrylic fibers

High

12 inches – no upper limit for custom built
spray machine

Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.

Cement in concrete prevents or significantly retards the oxidation of the interior base metal (rust) of CSP
Can accommodate bends and imperfections in host pipe
Large range of diameters can be selected within the range of the centrifugal mortar projecting machines.
Smooth interior surface may improve hydraulic characteristics by reducing roughness coefficient.
Lateral connections are easily handled

Specialized equipment and trained personnel needed. 
Cement is subject to break down if runoff is acidic and/or contains sulfates and mix design is not appropriate. See HDM Table 854.1A.
Control of infiltration required

Man-entry lining with pipe segments

FRP, FRC, HDPE, PVC

High

42 inches –
198 inches

Invert Repair for Large Diameter Pipes, Corrosion, Infiltation/Exfiltration

Can be manufactured in virtually any shape and length.
Lightweight and easy to handle.
Option for invert lining only.
Sections easily cut to form connections

Installation is labor intensive and slow.
Restraint system may be required during grouting.
HQ approval needed for plastic liners exceeding 60 inches.
Control of infiltration required

Internal Chemical Grouting
(joints)

Acrylamide gel, polyurethane foam, urethane gel, acrylic gel, and acrylate gel.

High

< 24 inches

Infiltration/Exfiltration at Joints

Robotic sealing packer used to access small diameter pipes.

Can be used to stop severe infiltration prior to other repairs.

20 years or less service life. Quality control difficult.
Acrylic gels limited for use in systems under the groundwater table. Success may depend on soil and moisture variability. Formulating the correct mixture may be dependent on trial and error on a case-by-case basis, rather than scientific principals. If conditions change, the grout may shrink. Grouting cannot be used for joints that are severely offset. It is also inappropriate for longitudinal cracks and severe circular cracks.
Specialized equipment and trained personnel needed.

Invert steel Armor Plating

High

> 24 inches

Invert Repair for Concrete and Metal Pipe

Provides abrasion resistance.
Can easily modify thickness to meet needs.
Limited to bottom third of pipe

Difficult to attach to RCP or plastic.
May not be appropriate in highly corrosive environments.

Stainless Steel or PVC Repair Sleeve with expanding polyurethane grout

Low

18 inches – 54 inches
(Stainless Steel)
18 inches – 108 inches
(PVC)

Infiltration at Joints

Remote installation for small diameter pipes.
Can be used to stop severe infiltration prior to other repairs.
Large range of diameters can be repaired.
Available in 18 inches, 24 inches and 36 inches individual lengths, which may be connected if, needed.
Can be used to repair deformed flexible pipe.

Local repairs only

8.1.2 Process Flow Charts

For guidance on the overall process for analyzing problems and solutions in conjunction with the Table of alternative repair techniques that are summarized in Index 8.1.1, see FHWA Culvert Repair Practices Manual Volume 1, Chapter 3, Figures 3.2, 3.3, 3.4 and Table 3.1 on pages 3-9, 3-10, 3-12 and 3-15:

  • Analysis of problems and solutions. Overall process
  • Determining the Cause and the Type of Problem
  • Process for Analysis of Potential Solutions
  • Summary of Information on Alternatives

This page last updated August 20, 2011