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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,
|
Med. |
18 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.
|
Need fairly large area for liner insertion/jacking pit
HQ approval needed for plastic liners exceeding 60 inches |
|
Fold and Form
|
Med. to High |
< 15 inches |
Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.
Smaller construction footprint than sliplining
|
PVC may become brittle in freezing temperatures. Specialized equipment and trained personnel needed.
Very limited sizes; little or no use for most projects.
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.
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:
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
|
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)
|
Low |
> 36 inches |
Cracks in RCP
Low resource commitment.
|
May be only a cosmetic repair if basic cause of the cracking is not determined and treated.
|
|
Invert Lining:
CRSP, or
Steel plate
|
Med. Med. |
> 72 inches > 48 inches |
Invert Repair for Concrete and Metal Pipe
High strength concrete and/or hard aggregate/or steel plate provides abrasion resistance.
|
Human entry only.
|
|
Internal
|
Low |
15 inches –
|
Infiltration/Exfiltration at Joints
Low resource commitment.
|
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
|
Med. to High |
<
18 inches
|
Invert Repair for non-human entry pipes, Corrosion, Infiltation/Exfiltration.
Smaller construction footprint than sliplining.
|
May be difficult to reform larger diameters with thick walls.
|
|
Machine Spiral Wound PVC |
High |
<108 inches
<
30 inches for radially expanded
|
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.
|
May become brittle upon freezing.
|
|
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
|
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
|
Specialized equipment and trained personnel needed.
|
|
Man-entry lining with pipe segments FRP, FRC, HDPE, PVC |
High |
42 inches –
|
Invert Repair for Large Diameter Pipes, Corrosion, Infiltation/Exfiltration
Can be manufactured in virtually any shape and length.
|
Installation is labor intensive and slow.
|
|
Internal Chemical Grouting
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.
|
|
Invert steel Armor Plating |
High |
> 24 inches |
Invert Repair for Concrete and Metal Pipe
Provides abrasion resistance.
|
Difficult to attach to RCP or plastic.
|
|
Stainless Steel or PVC Repair Sleeve with expanding polyurethane grout |
Low |
18 inches – 54 inches
|
Infiltration at Joints
Remote installation for small diameter pipes.
|
Local repairs only |
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
