Many countries are embarking to rehabilitate its aging sewer & water network where sewer infiltration and water loss can reach 50%. The presentation highlights the strategies to tender and implement efficient rehabilitation program with a preview of trenchless technologies in rehabilitation while highlighting the technical and contractual challenges.

1. TRENCHLESS REHABILITATION OF SEWER &
WATER NETWORKS - DUBAI APRIL 2018

2. Content
Problems & Solutions Methods in Water / Sewer Pipes
Public Sector Tenders - Water & Sewer Rehabilitation Projects
Rehabilitation BY Preserving Pipes - Robotics, Liners, Slip lining
Rehabilitation BY Pipe Replacement - Pipe Bursting , Reaming
Sewer Pipes Rehabilitation Considerations
Water Pipes Rehabilitation Considerations

3. 1. Problems & Solution Methods in Water / Sewer Pipes

4. Problems in Current Pipes
Infrastructure Systems
 Pipe systems undergo settlement which causes
leakage (waterlines), infiltration (gravity sewer
lines) and finally failure causing interruptions in
services and safety hazards as well.
 Metallic systems corrode , build up internal
deposit restricting flow and reducing water
quality leading to water discoloration.
 Now is the age of plastics, synthetic polymers
and PP / PE which has become leading materials
in renewing gas, sewer & water pipes

5. URBAN UTILITIES & FOUNDATION

6. Different Objectives! – Water Example
Pipe
Producer
Installer /
Maintainer
System
Owner /
Authority
End User

7. Why Trenchless Rehabilitation
 Least traffic disruptions
 Increased public safety
 Reduces Utility disturbance/shut downs by
avoiding interruption of high cost utility lines,
fiber optic lines, hi-pressure gas lines, etc.
 Avoids pavement removal and restoration
 Cost effective when considering open trench
and costs of disruption

8. Trenchless & Rehabilitation Chart
New Pipelines
•Auger Boring
(Perforators)
•Horizontal
Directional
Drilling (HDD)
•Micro-
Tunneling
•Pipe
Ramming
•Pipe Jacking
Rehabilitations
• Robotics (Sealing,
Spay Lining, Shotcrete,
etc.)
• Pipe Liners - Cured In
Place Pipe (CIPP), Strip
Liners
• Pipe Slipping – With or
W/O Grouting
• Pipe Replacement
(Bursting, Reaming,
Jacking, etc.)
Manholes
Maintenance
• Chemical
Grouting
• Coating
Systems
• Structural
Linings

9. Advantages of Trenchless
Rehabilitation
 Restoration of structural load capacity with extended life
expectancy
 Improved hydraulic capacity by reshaping the circular pipe
profile and replacement with higher performance pipes
 Short set-up time reduces rehabilitation time and labor
costs - Fastest repair option
 HOWEVER; Trenchless pipe rehabilitation works involves
the complete or partly break-off of the existing manhole
bench and channel for;
 Installation of the sealing packers for the Cured In Place Pipe
(CIPP) or the pipe bursting machines.
 The upsizing/ widening of the manhole duct for the pipe feed
 Adjustment of the manhole inlet according to the diameter/
inlet level of the new installed pipe.

10. Rehabilitation & Pipe Condition
 Partially Deteriorated Pipe - The original pipe can support
the soil and surcharge loads throughout the design life of
the rehabilitated pipe and the soil adjacent to the existing
pipe provides adequate side support. The pipe may have
longitudinal cracks and up to 10% distortion of the
diameter and in many instances has leaky joints.
 Fully Deteriorated Pipe - The original pipe is not
structurally sound and cannot support soil and live loads
nor is expected to reach this condition over the design life
of the rehabilitated pipe. This condition is evident when
sections of the original pipe are missing, the pipe has lost
its original shape, or the pipe has corroded due to the
effects of the fluid, atmosphere soil or applied loads.

11. Rehabilitations Cost Comparisons

12. Rehabilitations Ground Conditions

13. Water & Sewer Rehabilitation Projects
2. Public Sector Tenders

14. High Level Asset Management Plan -
Water & Wastewater Networks
 Pollution Issues
 Intermittent Discharges
 Condition Surveys
 Population Forecasting
 Climate Change
 CAPEX/OPEX Costs
 Incident Reporting
 Work Scheduling
Data capture and management facilitated by Geospatial
tools and incorporation of live telemetry data for pumping
operations and flows are critical.
 GIS Asset Data
 Operational Data
 CCTV Data
 Pumping Stations Data
 As built Maps / Data
 Future Schemes
 Historic Flooding /
Blockage
 Investigations

15. High Level Asset Management
Plan Allows ….
 Review of water and sewer system
operations to re-direct resources to
most pressing problems (proactive
vs. reactive).
 Prioritization of catchments on
needs, to focus investment on worst
performing assets to reduce impacts
(flooding, blockage, infiltration,
leakage, etc.)
 Development of prioritized programs
(optimized capital delivery) of
investment for business planning
purposes by linking business
strategy, CAPEX and operational
delivery.
 Network optimization through
consistent and auditable
methodologies

16. Tender Information Usually
Provided by the Public Authority
 AS-Built location drawings of the water / sewerage segments /
system of the project area;
 Available damage , infiltration, leakage data and known
structural defects in the project zones.
 Scheduled rehabilitation program. Working zones controlled by
boundary conditions to be identified.
 As built drawing identifying other services. Exploratory
excavations may still be needed.
 Available CCTV survey results, movies of the concerned sewer
lines, ultra-sonic ground water wave data, feeding lines flow
measurement, pressure, domestic water meter readings & leak
analysis.
Important Public Authority Disclaimer – “the Contractor is
responsible to carry out the field survey to check the accuracy of the
as-built information contained in the contract documents and those
supplied by other authorities”

17. Public Entity Pre-Tender
Survey / Investigations
In the Pre-Tender stage the Public Entity carries out CCTV
Survey of Sewers / Water Flow Measurement for water network
to;
 Identify problem in sewer infiltration, water leakage and
severe damages
 Estimate the infiltration and leakage (infiltration rates/km;
water loss estimate in the network, unaccounted for water,
etc.)
 Classification of damages
 Conduct hydrodynamic modeling
 Declaration of the rehabilitation measures
 Cost estimation and ranking for rehabilitation works
(Red = high priority, Yellow = medium, Green = low)

18. Rehabilitation Projects Scope of
works
 Procurement of all required permits including Way Leaves.
 Services exploratory locations & excavations - CCTV sonde - ultra-sonic
wave data for ground water detection.
 The diversion and control of traffic - Traffic Management Plan
 Maintaining of continuity of sewer, water & other service.
 Sealing / isolating pipeline section being rehabilitated / inspected
 Pipe cleaning / obstructions removal.
 Pre-installation pipe inspection by CCTV for sewer or flow measurement
for water networks
 Determining method of rehabilitation
 Backfilling and reinstatement of any excavated areas
 Maintaining public & workers safety.

19. CCTV Pipeline Condition Codes
The Standard CCTV Condition Codes are used in accordance with the coding
system of EN (DIN) 13508-2 identifying the inspected element
(S=Sewer, M=Manhole, L=Lateral)
 Structural Codes
 Crack Circumferential, Longitudinal, Multiple
 Deformed, Dipped Pipe
 Infiltration at Pipe Wall
 Joint Displaced, Faulty, Open
 Lateral Defective, Protruding
 Obstruction Permanent
 Pipe Holed, Broken, Collapsed
 Deformed Plastic Pipe
 Protective Lining Defective
 Surface Damage
 Service Codes
 Debris Greasy, Silt
 Encrustation Deposit
 Root Intrusion

20. General Notes on Rehabilitation
 Generally all manholes including the existing
benches and inlets/ channels demolished by the
contractor for any reason during rehabilitation
works must be restored
 Prior to re-establishing service connections, the new
pipes are allowed to relax and return to its original
shape for at least 24 hours as its likely to have been
stretched during the installation process. The same
applies to heat setting of lined pipes where time is
allowed for curing and cooling.
 Many of the described rehabilitation techniques can
be used for laterals rehabilitation. This usually
requires excavation at each connection point.
Consideration must be given as to how the service
connections are re-opened

21. Important; Works NOT Paid
Directly by Public Authorities;
Works that are not listed as specific tender items, but are required
for proper completion of the work are incidental to rehabilitation.
Some incidental items examples;
 All temporary works
 Public and authorities relations management.
 Protection to the existing utilities.
 Transport and/or store of excavated material
 Bypass and or over pumping necessary to divert or coping with
the upstream or downstream flows.
 Shoring and discharging / de-watering excavations
 All arrangements to carry out the installation works.
 Notifications to private property owners of scheduled works
 Cleaning and disinfecting any blow-back that occurs to
householders.
 Monitoring safety conditions especially poisonous gases in sewer
confined spaces

22. AT All TIMES THE CONTRACTOR
IS REQUIRED TO;
 Have back up backflow control in place to ensure that no
flooding of streets and/ or connected sewer/water laterals
occurs in addition to by-pass pumping equipment, suction
tankers and/or over pumping on standby.
 Whenever, services exploratory excavations for wastewater
laterals, other sewer pipelines, water mains, storm water
pipelines, electrical cables are needed, the work includes
surveying of horizontal and vertical positions and the
recording the information on a location plan
 Keep a record of the condition of private properties prior to
undertaking any work.
 Keep a record of water use for all quantities extracted from
Public Authority’s mains.

23. Particulars to Re-habilitation
Projects - Limitations of Work:
 Trial holes to locate other utility pipes like electricity,
telecommunications and gas especially old lines are often
needed. Peak season restrictions from concerned authorities can
apply to these excavations for fear of serves disruption.
 Some pipelines may pass beneath major roads; the obstructions
to traffic must be kept to a minimum.
 Usually ground water discharge into any sewer is restricted, if
allowed a settlement tank to trap silt/sand present in the
groundwater is needed.
 Rehabilitation procedures with regard to shock waves and
vibration arising from the use of pneumatic burst equipment
often have a detrimental effect on nearby services or structures.
 Ground dewatering can cause sinkholes far away from the site.
Underwater inspections by means of high resolution scanning
sonar may be needed.

24. Robotics, Liners, Slip Lining
3. Rehabilitation BY Preserving Pipes

25. PRE-PIPELINE INSTALLATION,
CLEANING & SERVICES DISCONNECTION
 Prior to pipe installations in all lining / pipe slip methods, the
existing pipeline must be thoroughly cleaned and de-scaled by
removing any debris, existing grease, solid deposits and tree root
penetration to restore a minimum of 90% - 95% of the pipe
cross-sectional area. Root intrusions, if any, are removed. In
Cured-In-Place Pipes (CIPP) in particular, it is necessary to
remove the roots completely.
 The locations of existing lateral connections must be identifies
and disconnected and all sewer / water flows diverted.
Protruding laterals / services, severely offset joints need to be
milled.
 All infiltrations (sewer lines) must be stopped. Pre-sealing by
robot technology.
 Damaged pipe areas are milled / brushed to make a sufficient gap
width and surface roughness to be put into an adhesive condition

26.  Infiltration sealing of
cracks and broken
fragments takes place
prior to pipeline
installation by means of
robotic repairs.
 Systems used are part
Liners & caps for lateral
services
ROBOTICS

27. Robotic Repair - Sealing of Cracks
and Broken Fragments
 Filling & Spackle
 Milling, filling/ spackle of the prepared pipe area
flush with the damage-free existing pipe wall with
plastic-modified cement mortar system.
 Grinding flush takes place after wards.

28. LINER SPRAY BY REMOTELY OPERATED
ROBOTIC SPRAY EQUIPMENT

29. Robotic Technologies
 Infiltration Treatment by Part Liner (each length up to 1.5 m)
 The part liner unit consists of a milling robot and packer equipped with a
remote controlled axial and radial rotatable color camera which can observe
the work.
 The part liner (ECR fiber glass mat with minimum 1400 g/m²) is glued
(conglutination) to the pipe with high adhesive epoxy resin material. The resin
should be suitable for high-pressure cleaning, be of high chemical resistance
and cure quickly without shrinking, density about 1.1 g/cm³. The minimum
thickness of the part liner is 3 mm and maximum wall thickness 5 mm.
 Other type of part liner is the installation of mechanical interlocked stainless
steel sleeves (installation length 400 mm) with interlocking mechanism and a
rubber seal made of permanently elastic ethylene propylene diene monomer
(EPDM) on the basis of compression.
 Cap Placement Systems;
 The cap profiles (short liner with shaped hose fitting) encloses the complete
pipe segment or parts of it in the connection area. The flange usually has a
minimum width in the main sewer of 50 mm with a minimum length in the
lateral inlet of 100 mm. ECR fiber glass or synthetic fibers are used with min 3
mm thickness.

30.  Pipe liners are designed
in accordance with BS EN
ISO 11296-4 (and BS EN
1619 for testing) –
"Plastics piping systems
for renovation of
underground non-
pressure drainage and
sewerage networks
lining with cured-in-
place pipes.”
 For Pressure Pipes the
standard is DIN EN ISO
11297
 The standard covers
material requirements,
construction methods,
and design parameters.
LINERS

31. Cured-In-Place Pipes - CIPP -
Preview
 For partially deteriorated gravity pipe - The liner is designed to
resist the hydrostatic loads due to groundwater, since the soil and
live loads are still being supported by the original pipe.
 For fully deteriorated gravity pipe - The liner pipe is expected to
carry all of the hydraulic, soil, and live loads by itself, as if the host
pipe is not present.
There are constructions and performance related limitations to the
use of CIPP for pipeline rehabilitation; like;
 The condition of the existing pipeline (odd-shaped pipe, deep pipe,
severely deteriorated pipe, difficult access, etc.),
 The maximum practical thickness of the liner, and the point where
CIPP lining is no longer a cost effective option.

32. Cured-In-Place Pipes - CIPP -
Process and Materials
 The CIPP process begins by cleaning the existing pipeline in preparation for the
installation of the liner.
 The liner consists of an absorbent, flexible, industrial grade felt tube with an
impermeable membrane on the inside surface. The size and length of the tube are
custom made. This makes CIPP an ideal method for odd sized or odd shaped pipes.
 The Resin is what hardens and ultimately gives the CIPP its strength. The material
property to determine the strength of the liner is the flexural modulus of elasticity
(250,000, 300,000, and 400,000 psi are common). The selected resin strength can
be used in conjunction with different thicknesses of felt to produce multiple
designs which can meet the requirements.
 Over time, the materials used for construction of CIPP will undergo deformation
(creep) when exposed to a constant load. Thus, a reduction factor (50%) is applied
to the initial flexural modulus of the resin.
 After laying the newly installed liner, it is then cured by either applying heating in
the forms of UV light source or circulating hot water, or by applying pressurized
steam to the liner. The applied heat causes the thermosetting resin in the felt to
cure and harden.
 After the resin has cured, the CIPP is cooled, resulting in a new pipe with a slightly
smaller inside diameter, but of the same general shape as the original pipe. The
expected service life of a cured-in-place liner is generally 50 years.

33. SPIRAL WOUND LINERS In large Diameter
Transmission Pipelines - Semi Structural

34. Process - Spiral Wound UPVC Liners –
SEMI STRUCTURAL

35. SEMI RIGID KEVLAR REINFORCED LINERS
- STRUCTURAL LINER

36.  Alternative to cured-in-
place liner or pipe
bursting (cracking).
 Slip Lining is faster as
the cracking hammer/
bursting tool is only
activated (dynamically
or statically) where
individual, localized
damages exist.
 Used whenever
hydraulic capacity of
the host pipe allows
reduction of the
existing pipe diameter.
SLIP LINING

37. Slip Lining - Semi Structural Pipe Liners
 Work in composite
with existing pipe.
 Provide some
additional strength.
 Provide new corrosion
resistant inner liner to
existing pipe.
 Bridge and repair all
leaks & defects.
 Distances can be up to
1 Km per section.
 HDPE mostly

38. Slip Lining - Structural Pipe Liners
 Work independently of
the existing pipeline.
Carry all loads.
 Can be lose fit or tight
fit (using die reduction -
swage Lining)
 Totally corrosion
resistant.
 Have very long life
expectancy (50 year
design)
 Bridge and repair all
existing leaks & defects.

39. Semi Structural - Folded PE Pipe
 To reduce the overall dimensions of the pipe it is folded into a U
shape. This folding can be done in the factory or at the site using
special equipment
 Once the pipe is folded it can easily be threaded through the old main
 Once in place the pipe can be expanded using water or steam pressure
 This technique is particularly suited to deep mains and mains with
bends and obstructions

40. Semi Structural - Tight Fit

41. Structural - Tight Fit (SWAGE LINING)
 Liner pipe drawn thorough a
die to reduce the outside
diameter by 10%
 The pipe is then drawn
though old pipeline by a
winch
 Once in place winch
uncoupled and pipe expands
to form close fit liner
 This is particularly well
suited to shallow mains with
no bends or obstructions

42.  Bursting For Brittle Pipes
 Dynamic
 Hydraulic
 Static
 Pipe Crushing (Implosion)
 Pipe Reaming (HDD)
 Pipe Splitting
 Micro - tunneling
 Pipe Eating
 Pipe Ejection (Pipe Jacking)
4. Rehabilitation BY Pipe replacement
Busting, Reaming, Splitting & Microtunneling Techniques

43.  Used for replacing worn
out and undersized
pipes with a new pipe of
the same or larger
diameter.
 Replacement pipes are
designed to withstand
earth loads and live
loads in the same
manner as they would
be for an open cut
situation.
PIPE BURSTING

44. Pipe Bursting – Preview
 The conical shaped bursting head (expander at the
nose of the machine) fractures the existing pipe into
as many small fragments and displaces the pipe
fragments outward into the surrounding soil.
 At the same time, a new flexible pipe (typically PP) is
pulled in behind the bursting head. Pipe bursting
machines are either pneumatically or hydraulically
powered. Static pull is also possible.
 The types of pipe suitable for bursting are typically
brittle materials such as vitrified clay, cast iron,
asbestos cement, and plain concrete. Lightly
reinforced or heavily deteriorated reinforced
concrete pipe may be replaced by pipe bursting.

45. Pipe Bursting Systems –
(Strychowckyj 1998)
 Pneumatic Bursting - The most commonly used system. This method utilizes a
percussion head (similar to an impact mole) to fracture and break the pipe. A cable is
attached to the front of the mole and a winch provides tension to keep the bursting head
pressed against the pipe wall and to aid in pulling the new pipe in behind the mole.
 Hydraulic Expansion - The hydraulic expansion system utilizes a bursting head, which
can be expanded outward to break the existing pipe. Hydraulic pressure is used to
expand the head radially outward, breaking a section of the pipe, and pushing the
fractured pieces into the surrounding soil. The head is then contracted and pulled
forward with a winch, pulling in the new pipe behind it.
 Static Pull - The force for breaking and displacing the pipe comes only from pulling the
bursting head forward. The cone shaped bursting head converts the horizontal tensile
forces into radial forces which fracture the pipe. The tensile forces required to burst the
existing pipe and pull in the new pipe are significant. A pulling rod assembly is used in
lieu of a winch and cable system.
 Pipe Crushing (Implosion) - The implosion system incorporates a crushing head, which
fits around the outside diameter of the existing pipe. As the head is pulled forward, the
crushing head breaks the existing pipe and forces the fragments inwards (into the pipe
void). A steel cone follows the crushing head and pushes the pipe fragments outward,
making room for the new pipe which is pulled in behind the steel cone.

46. Pipe Bursting – Materials
 For most installations, standard sewer or water main pipe flexible
materials with special restrained or bell-less joints intended for
directional drilling designed to withstand high tensile forces, are
suitable.
 The most common pipe material utilized is polypropylene (PP) and to a
lesser extent polyethylene (PE). (moderate tensile forces occurs during
pipe bursting)
 When PP / PE pipes are used, it is a common for the pipe to be made of or
lined with a light color material to facilitate future CCTV inspection.
 The wall thickness for PP / PE pipes are designed to withstand earth and
live loads plus a 10% thickness provision for to account for scarring of
the outer surface as polyethylene is more susceptible to damage than
other pipe materials by the broken fragment of existing pipe.
 The normal bursting length is between 300 and 400 feet, while the size
of the pipes currently being replaced by pipe bursting ranges from 2 to
36 inches (and is increasing). The most common pipe replacement is
size-for-size; however, the pipe can be upsized.

47. Pneumatic / Hydraulic Pipe
Expansion Bursting
 Pneumatic / hydraulic breaker is pulled through old main to break
pipe. Same sized or larger PE pipe drawn through behind the breaker.
 Important to use PP / PE material with a high resistance to slow crack
growth as many sharp metal or concrete shards remain close.

48. Static Pull Bursting
 The bursting head converts horizontal pull forces into radial
forces which fracture the pipe.
 A pulling rod assembly is used in lieu of a winch and cable
system.

49. Equipment (dynamic / static)
Capabilities for Pipe Bursting
 The method of connection of the lining pipe to the expander are such that stresses
transmitted to the lining pipe shall not damage the lining pipes nor exceed its
tensile capacity. Also measures need to be taken to ensure the lining pipe does not
become separated from the pipe expander should the system employ a pipe jacking
or tensioning technique.
 The pipe bursting machines usually have the capability of dealing with minor
quantities of un-reinforced concrete up to 150 mm nominal thickness surrounding
the pipes, and for pipes laid on a concrete cradle, without being deflected off line
and level.
 Most pipe bursting machines are capable of working under a hydrostatic head of
approximately 2.5 m, and a certain depth from the surface. The design prevents
jamming of moving parts or other malfunction from the ingress of groundwater or
ground particles during operation.
 The winch ( or pulling rod assembly in case of static pull) usually applies a constant
/ continuous load type, fitted with a direct reading load gauge to measure the
winching load, and can automatically disengage when the load exceeds a preset
maximum load. The winch, cable and cable drum are provided with safety cages and
supports.

50. Effect of Pipe Bursting on the
Surrounding Environment
 Pipe bursting operations result in soil displacement. Even when the
replacement is size for size, soil is displaced since the bursting head has
a diameter greater than that of the replacement pipe.
 The soil expands in the direction of least resistance and can cause
heaving at the surface. The amount of displacement depends on the
degree of upsizing, the existing soil properties, and the depth of the
bursting.
 Heaving of existing ground surface is most likely when the existing pipe
is shallow or already large diameter pipes are upsized. The potential for
heaving need to be considered, especially when bursting under existing
pavements or structures.
 Adjacent utilities can also be affected by pipe bursting. In general, if
there are deteriorated utilities within 2-3 pipe diameters of the bursting
operation, there is potential for damage. Damage to adjacent services or
structures can be minimized by creating a temporary excavation along
the service or structure.

51.  Pipe reaming is a
modified version of the
back reaming method
used for directional
drilling.
PIPE REAMING (HDD)

52. Pipe Reaming
Pipe reaming is bursting technique that utilize cable which is thread
through the host pipe from the receiving pit to the launch pit. The
cable is attached to a pull plate / head on the end of the pipe furthest
from the receiving pit.
The reaming head is pulled back through the pipe as the reamer
crushes and pulverizes the existing pipe while the new pipe is being
pulled. The pipe fragments and any excess soil required for upsizing
are removed via a slurry system.

53.  Rather than bursting the pipe, it is split open and expanded.
 Pipe splitting is a method used for pipes that are not brittle like
plastic pipes.
 A rotary slitter wheels make an initial longitudinal cut along the
bottom of the pipe. Next, a hardened sail blade splits the pipe
along the bottom.
 Finally, the pipe is “unwrapped,” or expanded, creating a hole
immediately behind the splitter for the new pipe while the old
pipe is displaced above the new pipe.
PIPE SPLITTING

54. Pipe Eating (micro tunneling) :
 Pipe eating is a modified micro tunneling system in which the existing
pipe is crushed by the micro tunneling head and, along with any
excess soil is removed through the new pipeline by a slurry system.
 The new pipe is jacked in immediately behind the micro tunneling
machine. This system also allows line and grade adjustments to be
made.
Pipe Ejection (Pipe Jacking) :
 Pipe ejection uses modified pipe jacking techniques to remove the old
pipe to allow the installation of rigid pipes like steel, ductile iron,
concrete.
 The replacement pipe is placed against the old pipe and, as the new
pipe section is jacked, the old pipe is pushed out into the reception
pit.
 This method requires that the structural condition of the existing
pipe be in sufficient condition to withstand the jacking forces
produced.
FROM MICRO - TUNNELING

55. Recap - Which Replacement
Method?
 Spiral / Strip Liners – May not be cost effective!
 Slip Lining (Pipes) – (semi structural & structural), can be the
first option if reduction in hydraulic capacity is possible.
 Pipe Bursting – Used for bursting brittle materials such as
vitrified clay, cast iron, asbestos cement, plain concrete and
lightly reinforced or heavily deteriorated reinforced concrete.
 Pipe Reaming (reverse HDD) – similar to bursting but used for
more brittle materials that does not requires dynamic crushing
force.
 Pipe Splitting – Used for splitting ductile iron, steel, and plastic
that are not suitable for pipe bursting.
 Pipe Eating / Jacking (Micro Tunneling) – Used for crushing
almost all pipe types and allow the installation of rigid pipes
like steel, ductile iron, concrete.

56. COMMON REHABILITATION PIPE
PRODUCTS
 CURED-IN-PLACE PIPES - CIPP
 CURED-IN-PLACE PIPE (CIPP) RESIN-IMPREGNATED TUBE
 Bursting (Cracking/ Upsizing)
 POLYPROPYLENE PIPES WITH HIGH MODULUS OF ELASTICITY (PP-HM)
 Tight-In-Pipe (TIP)
 POLYPROPYLENE PIPES WITH HIGH MODULUS OF ELASTICITY (PP-HM)
 Slip Lining (Structural)
 DEFORMED HIGH DENSITY POLYETHYLENE PIPE LINING (DRP-HDPE)
 CENTRIFUGALLY CAST FIBERGLASS REINFORCED POLYMER MORTAR
PIPE (CCFRPM) 18”-48”
 UNPLASTICIED POLYVINYL CHLORIDE PIPE (UPVC) PIPE , 12”-48”

57. Polypropylene Pipes (PP-HM)
PP-HM (polypropylene with a high modulus of elasticity) are available as long pipes
(connected by butt-fusion or electro-fusion) or as short pipes with plug-in connections.
The mechanical characteristics of PP-HM pipes are especially beneficial for trenchless
installation techniques like pipe bursting or tight-in-pipe compared to PE:
 Lower density (900 kgm‐3) in relation to polyethylene (950 kgm‐3) i.e. lower unit
weight per product (hence easier handling and installation)
 Increased surface hardness and toughness compared to PE and other PP types. Higher
E‐modulus (1200 MPa ‐1500 MPa) in relation to polyethylene (800 –1000MPa)
 Abrasive and corrosion resistant to chemical agents and contaminated soils
 Very good thermal resistance (application range from -20° to +90°C), , especially
important for sewage systems in warm areas
 Excellent hydraulic performance, No blockage debris and encrustations, no root
penetration
Some limitations of PP pipes are:
 Slightly susceptible to stress cracking,
 Significant length changes possible depending on temperature changes,
 Electro-fusion joints cannot be pulled into the ground.

58. 5. SEWER Pipes Rehabilitation Considerations
Rehabilitation Method & Pipes Selection

59. Sewer Rehabilitation -
Preparation
Before rehabilitation of the existing sewer begins, the Contractor must;
 Clean the sewer & manholes
 Conduct pre commencement CCTV and calibration of the
sewer & manholes
 Order the materials based on the results of the CCTV;
 Structural condition of the pipeline.
 Cleanliness and operating condition of the pipeline.
 Location and amount of deposits, tree roots or other obstructions.
 Location and amount of infiltration / leakage.
 Stop pipes infiltration based on the results of the CCTV.
To carry out cleaning , a cleaning vehicle equipped with a combination of
high pressure flushing and suction system (with water recovery technology
that allows the water to be separated from the suctioned sludge by a self-
cleaning filter system) is needed.
Pre- installation CCTV works are generally driven in the direction of flow. An
electrically driven camera vehicle with wheels or tracks is used. The rate of
travel is variable, maximum allowed is usually 15 cm/s.

60. CCTV Electronic Data Format &
Deliverables
 Digital record in color photographic or video film in the
format requested.
 Video summary sheets are supplied with video record
contains the following information for each inspection;
 Header summary sheet containing; Date and Time; Contract
Number; Name of the Contractor; Video record (DVD) number
 Mini-catchment; Area name and street name
 Inspected pipeline diameter / number
 Upstream / Downstream manhole
 Estimate of the severity of any deposits, dips or root
intrusions are submitted with the log sheets whether or not
the defects are visible in the submitted video record.

61. CCTV Inspection Equipment
3D stereoscopic cameras are generally used. Inspections carried out with the
camera in pan or tilt mode while in motion are usually not permitted. inferior
picture quality can include;
 Camera out of focus
 Insufficient or excessive lighting
 Fog or steam in the pipeline
 Condensation on the lens
 Temporary discharge of water down the pipe
 Debris or spider webs over the lens due to insufficient cleaning
 Camera not stationary during still picture capture
 Camera moving too fast through the pipe
 Camera not centered along the axis of the pipeline
 Camera moving along a pipeline while in a pan or tilt position
Where the pipe material is not conducive to CCTV inspections, such as white
reflective or black, light absorbing polyethylene pipe, the light intensity need
to be adjusted. The CCTV monitor should display, the camera's position in the
pipeline relative the center of the start manhole.

62. Particulars to Sewer
Re-habilitation Projects
 Generally sewer pipes are silted by sand, stones, gravel and other
materials (40% is common). In addition if no fat separators are used in
restaurants, sewer pipes are expected to be contaminated with fat
deposition.
 Flows are typically cyclic during daytime.
 During rainy conditions the flow within the sewer is likely to increase
due to infiltration.
 Diversions may not always be possible; Contractors may need to work
with live sewer flows.
 Sewage reagents / substances are highly corrosive
 High levels of hydrogen sulphide gas and other noxious gases exist in the
sewerage system , thus employees entering live manholes, sewers or wet
wells must wear breathing apparatuses to counter Oxygen Depletion.
 Other equipment / protection is needed from Biological Contamination
and Pathogenic Organisms.

63. 6. WATER Pipes Rehabilitation Considerations
Water Leak Detection (WLD) Tenders Particulars – Flow
Measurement

64. Water Leak Detection(WLD)
Rehabilitation Projects Notes
 Water transmission pipelines are generally medium to large
diameter , reasonably straight with limited tapings, tees & fittings.
 Water distribution pipelines often are smaller in diameter with high
number of service connections.
 WLD contracts evolved from finding leaks only, to water
management of the Network (minimize network water loss).
Current tenders stress on;
 Flow measurement & leak analysis.
 Water Leak Detection (WLD).
 Repair pipe leakage.
 Reduce the water loss in the Network.
 The disadvantage of WLD ONLY type of contract:
 Water loss is not considered in these projects - does not reflect the actual
condition of the network
 Contractor spends time & effort to do WLD but he could not be paid if the
network shows no leak.
 Public Authority has to coordinate & cooperate with many contractors at
the same time for same project.

65. New WLD Projects Scope Cover
The Followings:
 Updating as-built drawings.
 Evaluating all Network components (valves, water meters, etc.)
including the use of ultra-sonic ground water wave data
 Measuring the Network pressure to determine best time to do WLD.
 Establishing working zones controlled by boundary valves to
measure flow on the feeding line to each zone.
 Calculating unaccounted for water (UFW) by analyzing the water
flow into zones in comparison to the water consumption from
domestic water meters.
Usually If the water loss in the Network is > (10%), then WLD is done
to find & repair leaks. In this case Contractor payment is scaled with
water loss improvement percentage. For example Contractor is paid;
 (100%) of BOQ if he minimizes water loss to < (10%).
 (75%) of BOQ if he minimizes water loss to < (15%).
 (50%) of BOQ if he minimizes water loss to < (20%).
 (25%) of BOQ if he minimizes water loss to < (25%).

66. Takeaways
There are now many extremely competent trenchless forms of
pipeline rehabilitation methods available that are designed to
prevent or cure leaking water pipelines and sewer infiltration.
The correct specification and application of these methods will
result in a dramatic reduction in water loss much less infiltration to
sewer systems.

67. loayg@works.gov.bh; loay.ghz@gmail.com
00973-36711547
http://bh.linkedin.com/in/loayghazaleh