Pipe Bursting
Over the next 12 years, the City of Atlanta
will inspect, repair and where necessary, replace every foot of the
2,200 miles of sanitary sewers. This unprecedented $1.2 billion project
is an integral part of the City’s
comprehensive efforts to meet and surpass all federal
and state water quality standards.
The successful completion of the Clean Water Atlanta projects
will benefit Atlanta’s citizens and ratepayers, and our
neighbors downstream and throughout the region by providing the
infrastructure necessary to improve water quality and sustain
Atlanta’s economic vitality.
The SSES project is the first step in bringing Atlanta’s aging
sewer system up to world class/modern-day standards and protecting Atlanta
ratepayers’ quality of life by eliminating Sanitary Sewer Overflows
(SSOs). Through the efforts of the SSES, approximately 60,000 manholes
and 2,200 miles of sanitary sewers will be inspected for cracks, collapses,
and blockages. After extensive investigation and documentation of defects
is completed, a rehabilitation plan will be developed, identifying necessary
sewer repairs and replacement. In severe situations, immediate repair
may be required.
This document explains a method of sewer rehabilitation known as Pipe
Bursting that may be used during the SSES project. It also outlines
what you might expect during the project.
What is pipe bursting?
Pipe bursting is a method for inserting a new plastic pipe of equal
or larger diameter into an existing pipeline by bursting open the existing
pipe and pulling or pushing the new pipe into the old pipe and expanded
surrounding soil. The new pipe is simultaneously inserted into the enlarged
hole created by the burster (or expander). This concept was first developed
in Europe to replace cast-iron, gas-distribution pipes with minimum
impact to surface improvements. Pipe bursting has been used in the United
States since 1986 for rehabilitating up to one million linear feet of
pipe per year. The following figure provides a schematic view of the
process of pipe bursting.
What conditions allow for pipe bursting methods to be used?
Typical pipe diameters for this method range from 4 inches to 36 inches,
though pipes aslarge as 42-inches have been burst.
Pipe bursting is suitable for replacing pipes made of brittle material
such as vitrified clay, un-reinforced concrete, asbestos cement, some
polyvinyl chloride (PVC), and cast iron. It is less appropriate for
the replacement of steel, ductile iron, reinforced concrete pipes, polyethylene
(PE) pipes, or composite, though methods for pre-cracking/splitting
and then bursting these pipe materials are being developed. Bursting
progress of 2 to 10-feet per minute is possible.
What are the benefits of pipe bursting?
Pipe bursting has several advantages over open-cut trenching and other
trenchless rehabilitation methods:
- Pipe bursting allows for replacement of pipes
without disturbing surface structures.
- Potential problems with existing pipes are
minimized because pipe-bursting methods follow
the existing pipe path.
- For smaller sizes of pipe, pipe bursting is
the only trenchless technology that can be used
to upsize the existing pipe.
- Because it is trenchless, excavation is minimized,
which lessens effects on existing landscaping
and structures. The bursting heads on the piercing
tool can be removed at the end of the line so
that the tools may be removed through the new
line. This can eliminate the need for an exit
pit in some instances.
- Pipe bursting reduces the amount of site restoration
required.
Why does the City need access to my property for 180 days?
The actual process of pipe bursting will likely take less than one day to complete.
However, there are several activities that may require access to property
to ensure rehabilitation is successfully completed; these activities include
the following:
1. Planning and logistics for construction purposes.
2. Inventory of fences, trees, etc. that may impede free access for construction/maintenance
equipment.
3. Determine location of proposed cleanouts and existing private service
connections to main sewer.
4. Assess logistics to disconnect/reconnect service connections.
5. Conduct soil testing as needed.
6. Perform landscaping pre-construction survey and protection plan and post
pipe bursting restoration plan and work.
7. Pre- and post-pipe bursting building surveys (internal and external).
8. The management of flows from property – planning and actual maintenance
of flows.
9. Dye testing to confirm abandoned as opposed to active connections as well
as connectivity between buildings and sewers.
10. Meet with property owner to address questions and to obtain permission
to access sewer through property, where required.
For additional SSES Project information, please call
the CWA Hotline at 404.529.9211
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