Over the last 15 years, new advances in trenchless technologies have emerged across Europe and are finding their way into the United States. One of the fastest growing methods involves pipe bursting of existing pipe and replacement with new larger diameter pipe. The existing pipe is shattered into small pieces and pushed into the surrounding soil. A new pipe of like or larger size is then towed into the borehole. Pipe bursting can be used for water transmission mains,
wastewater force mains, and gravity sewer lines with excellent results. However, there are some instances where conventional open cut and replacement of the existing pipe is necessary. Before any design is undergone using trenchless pipe bursting technology or conventional open cut replacement, an analysis should be performed which provides an investigation of the following areas:
- The design requirements for pit size, trench requirements, pipe depth, pipe materials, and disinfection for the different types of line replacement.
- The pros and cons associated with each method, including but not limited to handling and disposal of existing pipe, pipe material limitations for new pipe, system operational requirements, and excavation limits.
- Permitting requirements for the different methods.
- A cost comparison of the different methods.
Following a location specific engineering analysis of the different methods, a determination can be made as to what type of method should be employed for a specific system. This paper will discuss each of those four elements and provide results of an analysis performed in Kissimmee, Florida.