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Pr oject Considerations for Pipe Replacement Methods 275

It is noted that the above guidelines do not apply to applications
with significant surface loads, such as vehicular traffic. For such
cases, minimal depth requirements would also apply to avoid the
effect of large surface loads. In addition, the ability of the pipe to suc-
cessfully perform its long term function, including the ability to with-
stand external soil loads as well as internal operating pressure, should
be confirmed, using conventional design procedures (PPI, 2008).

6.11 Summary
This chapter presented pipe replacement methods, primarily based
on the use of HDPE pipe. Although other pipe materials may be used
for pipe bursting, many references are made to HDPE since HDPE is
most commonly used material for this application. In comparison to
other renewal methods, including conventional open-cut construc-
tion, pipe bursting is often the method of choice when the existing
pipe has few service lateral connections, is significantly deteriorated
and, most importantly, requires additional capacity. This chapter dis-
cussed the predesign, design, and construction phases of pipe burst-
ing. In addition, a relatively simple concept for estimating the pulling
loads applied to the new pipe is provided to help determine the gen-
eral feasibility of the HDPE pipe to withstand these forces. While PE
pipe was used for pipe loading calculations, similar concept can be
used for calculating loads on other types of pipe materials. The cor-
responding estimates allow the selection of an appropriate pipe wall
thickness (DR value).
Polyethylene pipe has been most commonly used as a new
replacement pipe, but other materials have also been successfully
used; see Sec. 6.5. The reference to HDPE in this chapter by no means
implies that this book endorses or recommends use of HDPE pipe
over other types of pipe materials, a decision that needs to be made
by the project owner and design engineer, considering specific project
and site conditions. Chapter 4 presents a full discussion of different
pipe materials and advantages and limitations of each.