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Existing Pipe Displaced

Pipe bursting and pipe splitting are trenchless methods used to replace existing pipelines in the same alignment without physically removing the existing pipeline. Bursting and splitting, by using the existing alignment to replace a pipe, avoids the need to secure additional right-of-way to install the replacement pipe. Bursting and splitting can be used to upsize the pipeline increasing its flow capacity. Pipe bursting was initially developed in the 1980s to replace small diameter cast iron gas distribution lines but has since grown in acceptance as an effective method for replacing pipelines diverse in size, material type, and function including water, sewer, or gas pipelines. Pipe bursting is used to replace brittle pipes such as clay, concrete and cast iron through the application of a static or pneumatic bursting head to fragment the existing pipe. Simultaneously, a new product pipe attached to the back of the bursting head is installed in the same alignment as the original pipe. The pipe bursting process consists of advancing a conical-shaped bursting head that has a diameter 50 to 100 mm larger than the new replacement pipe, through the existing pipe. The radial expansion caused by the geometry of the bursting head displaces the existing pipe fragments into the surrounding soil and the oversizing of the bursting head serves to reduce the drag on the replacement pipe as it is pulled through the displaced ground. Pipe splitting is used to replace ductile pipes which are not suitable for fragmentation using a bursting approach. In pipe splitting, a cutting blade is used to slice open the existing pipe and then a shaped expansion head opens out the split pipe to make room for the replacement pipe.

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