Guidelines For Pipe Bursting Technology

By Matt Timberlake, President, Ted Berry Trenchless Technologies Team LLC | October 2012, Vol. 67 No. 10
Pneumatic pipe bursting.

Pipe bursting is a widely used and proven method for replacing underground utility lines that convey critical materials like water, sewer, gas, and others. Pipe bursting is a trenchless replacement method in which an existing pipe is broken either by brittle fracture or by splitting, using an internal, mechanically applied force by a bursting tool.

At the same time, a new pipe of the same or larger diameter is pulled in, replacing the existing pipe. The back end of the bursting head is connected to the new pipe and the front end is connected to a cable or pulling rod. The new pipe and bursting head are launched from the insertion pit, and the cable or pulling rod is pulled from the receiving pit. The energy (or power source) which moves the bursting tool forward to break the existing pipe comes from pulling cable or rods, hydraulic power to the head, or pneumatic power to the head, depending on the bursting system design.

This energy (or power) is converted to a fracturing force on the existing pipe breaking it and temporarily expanding the diameter of the cavity. The bursting head is pulled through the pipe creating a temporary cavity and pulling behind it the new pipe from the insertion pit.

Static pipe bursting.

Classifications
Pipe bursting systems are primarily classified as: (1) pneumatic pipe bursting and (2) static pipe bursting. The differences among these are in the source of energy and the method of breaking the old pipe, and some consequent differences in operation.

The selection of a specific replacement method depends on geotechnical conditions, degree of upsizing required, type of new pipe, construction of the existing pipeline, depth and profile of the existing pipeline, availability of experienced contractors and equipment, risk assessment, and other site-specific issues. Existing pipe types are classified as either “fracturable” or “non-fracturable” which characterizes the way they are “burst” or “split.” Most pipe materials common to water, sewer, and gas construction since the late 1800s are candidates for bursting; however each type will have special considerations regarding the method and specific tooling required to properly break and expand the fractured pipe.

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