1
Introduction toTrenchless Technology
Continuous Trenching
2
Old roads, old pipes ?
• Superb construction• Little maintenance • Low operational costs
• When to rehabilitate?
JACK
New roads, old pipes?
3
We are not alone!
Jack appears in different figures!
………but mostly not at the same time!
Jack’s appearance
Needs to be • Minimized or banished
• Find other ways of rehabilitation• Less damage to pavement• Less inconvenience to customers
4
Solution to JACK
Trenchless Technologies
Trenchless Technology
Techniques for utility line installation, replacement, rehabilitation, inspection, location and leak
detection,with minimum excavation from the ground surface.
North American Society of Trenchless Technology (NASTT)
5
Key PointsMinimal surface excavation
Alternative to open cut excavation
Can have entrance and exit surface excavations – JACK!!!!
Pipelines usually have diameters less than 900 mm (36 inches) - non person entry
Key Points (Continued)Typically considers only urban utilities:
Water and wastewater systemsGas, petroleum and chemical pipelines Electrical and communications networksAccess ways and other small diameter tunnels
6
Excludes: Large tunnels (< 1%)
Chunnel
World largest tunneling machine(14.2 m in diameter)
people
Method ClassificationMany classification systems proposedNo industry standardGenerally TT methods classified into four broad categories
7
Broad Categories
TrenchlessTechnologies
ConditionAssessment
On-lineReplacement
RehabilitationRepair
NewInstallations
LocatingMapping
AssetManagement
New Installations
8
New Installations
NewInstallations
Non-SteeringMethods
SteeringMethods
MolingPipe RammingAuger Boring
MicrotunnellingHorizontal Directional Drilling
Pipe Jacking
On-line Method
9
On-line MethodPipe bursting
Gravity Pipesvitrified clay, brick, concrete, steel, ductile & cast iron, asbestos cement (transite), pitch fibreHDPE,PVC etc..
10
Pressure PipesPrestressed Concrete Cylinder Pipes (PCCP)
AWWA C301 and C303, lined, embedded core, bar wrapped
SteelIron (cast and ductile)Asbestos cement (transite)Wood (solid and stave)HDPEPVCetc..
Pipe MaterialsNon-metallic
Wood stave pipePolyethylene
MDPEHDPE
PVCConcretePolymer concreteAsbestos cementPitch fibre
MetallicCast ironDuctile ironCopperSteelPCCP
11
Pipeline AccessGRAVITY Pipelines
Partial pipe flow Interior access readily available by person, camera, and non destructive testing (NDT) toolsPipeline inspection performed live or off line
Pressure PipelinesFull pipe flowTypically small diameter than gravity pipelinesInterior access limited (pressure, contamination and disinfection)Interior inspection usually requires pipe Sto be taken off line
Pipeline Condition AssessmentPipe condition rating
Deterioration state?Video camera imaging (CCTV)Acoustic methodsMagnetic methods
12
SaharaSahara®®: System: SystemReal Time Data ProcessingReal Time Data Processing
Exact LocationsExact Locations
Corroded Wires & CylinderCorroded Wires & Cylinder
Unknown Leak!
13
Common Pipe DeteriorationMetallic pipe
Corrosion (reduced pipe wall thickness)
Micro cracks in welds
Leaking joints
Non-metallic pipeCracks FracturesDeformationCollapse
TRENCHLESS PIPELINE REPAIR
14
Trenchless Pipeline Repair
GOALReturn a defective pipeline to
a serviceable condition without replacement
How you reach that goal is the key!
Lining - Technologies
Cured-in-Place Pipe (CIPP)
Main Line
Close-Fit Lining
Slip Lining Spray on
Proprietary Technologies
15
CIPP
Before
After
Close Fit Lining
16
Slip Lining
Rehabilitation
Cement mortarEpoxy
Spray on linings
17
Water and Sewer By-Pass
Trenchless Technologies
Tools in a Tool box
18
GrowingTrenchlessIndustry Water
Sewer2005
2004
2005
2004
Water
Sewer
REHAB
NEW
Municipal Survey Results
4.28/5.0
19
Where are those utilities?
20
Gas Main in a Sewer Lateral
21
Clearing a Lateral Blockage?
Utility Location and Mapping
22
Pipe line location“As built” or “As Recorded” drawings
Not accurateOften do not know where it is
(plan or depth)Cost of not knowing:
Line hitsIncreased construction costs
Subsurface Utility Engineering (SUE)
Pipe line locationCost of not knowing:
Line hitsIncreased construction costs
Subsurface Utility Engineering (SUE)
23
Cost of Not Knowing
Basic Tenets of SUESUE Quality Levels
24
ASCE Standard GuidelineASCE Standard Guideline
Quality Level “D”
Utility Contact PhaseRecords Research
25
Quality Level “C”(Visible Features)
Quality Level “B”
Determine Horizontal Alignment
26
Typical QL-B Designating ProjectElectromagneticMagnetometerResonant SonicsAcousticalPulse InductionGround Penetrating Radar
Typical GPR Survey0 -
10 -
20 -
30 -
Tim
e (n
s)
0 10 20Position (m)
Utility
Soil fill horizon
27
Quality Level “A”Utility ExposedAccurate X,Y, Z LocatingSize, Material and Condition
Utility Locating
Survey/Data ManagementConventionalGPSSUMGIS
28
Mobile GIS?
Utility Locating Quality Level “A”Non-Destructive ExcavationAir/Water & Vacuum Units
29
Existing Water and SUE Data
Existing Water and SUE Data
30
Existing Water and SUE Data
What is Cost of Not Knowing?Studies show that there is a payback of at
least $4.00 for every $1 spent on SUE.Reduced construction delaysImproved asset operation maintenance and planningEffective spending of rehabilitation $$:
One Ontario relined cement mortar pipe beside it was labeled on GIS system as unlined DI.Liner wrinkled and had to be removed
31
Trenchless Technologyvs.
Open cut excavation
Social CostsEconomic:
Traffic disruptionPedestrian disruptionCommercial and business disruption
Environmental:Noise and vibration
32
Social Costs (con’t)Safety
Worker safetyEmergency service access
Indirect costsLoss of residual life of adjacent utilities and pavement structures
Social Costs
Not traditionally included in construction costsSometimes difficult to quantify or specifyBecoming more relevant for rehabilitation and construction in urban areas
33
Social Costs
Social Costs
34
Environmental Costs
Typical Urban Project Costs
Restoration
75%
Materials 5%
Construction
20%
35
Typical Urban ProjectSocial costs savings
Traffic delays (cars & people)Economic loses (business)
EnvironmentalNoiseGreenhouse gases
Public perception
Advantages of TT
New installationsFaster pipe installationEnvironmentally friendly???Lower social costsLess labour intensiveLower green house gas emissions?Deeper services
RehabilitationLimited excavationFastLow social costsLine remains in serviceLower construction cost???
36
TT LimitationsNew construction
Limited contract specifications availableInstallation impact on pipe or other buried structures??Contractor experience
Who takes the risk?
RehabilitationQuality assurance
Materials, construction
Industry marketingInstallation cost?Inspection techniquesDesign techniquesFailures - cost of not knowing