Page 300 - Trenchless Technology Piping Installation and Inspection

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FIGURE 6.20 Protecting the HDPE pipe from grooves using wheels on the bucket.
(Source: Handbook of Polyethylene Pipe, 2008.)

If the PE replacement pipe will be dragged for a long distance
over rough surface or pavement, the contractor can reduce the risk of
scratching the pipe by placing it on cut-outs of available (scrap) PE or
PVC pipe to keep the pipe off the rough surface. Sometimes it is nec-
essary for the contractor to push down on the replacement HDPE
pipe with the bucket of the excavator to ensure that the HDPE pipe is
properly aligned with the existing pipe at the entry point in the inser-
tion shaft (see Fig. 6.12), in the event the shaft is not of sufficient
length. Wheels similar to those shown in Fig. 6.20 reduce the risk of
grooves or scratches on the HDPE pipe. When the head of the pipe
reaches the pulling shaft, the pipe should be inspected for surface
damage. Surface scratches or defects in excess of 10 percent of
the wall thickness should be rejected.
6.9.13 As-Built Drawings
As-built drawings are usually required for any underground utility
construction including pipe-bursting projects. The bursting contrac-
tor should mark the new pipe, manholes, ancillary structure informa-
tion on a copy of the drawings marked and dedicated as the as-built.
The contractor should document on these drawings any changes to
the original layout of the underground utilities and structures that
occurred during the construction phase. For example, rerouting any
utility due to the excavation of the shafts, reconfiguration of other
utilities required for bypass pumping, and others, should be marked
on the as-built drawings. These changes shown on the as-built
drawings should be verified and used to update the corresponding,
certified-record electronic files (GIS) for the utility.

6.9.14 Contingency Plan
An important submittal in trenchless technology projects is the con-
tractor’s contingency plan. Most contractors have contingency plans