How to backfill the excavation

Placement of backfill is as defined and designated in this section.

The contractor must excavate, supply materials and construct all manholes in accordance with the Drawings, subject to the tolerances specified in Tolerances. N25 Grade concrete must be used, unless otherwise shown on the drawings.

The contractor must carry out an internal visual inspection of pipelines larger than DN 600 nominal size after compaction of the backfill. All defects in jointing and obvious points of infiltration must be noted and repaired to the satisfaction of the Superintendent

Auditing is a process which can be used to verify the output of a supplier's activity or process conforms to the requirements of the customer.

We require Survey Control (Registered PSM) information for the purpose of audits, during or following completion of the Works and CAD files.

To enable us to undertake field audits during or after the construction period and to verify submitted information, survey information must be supplied on request.

Find out our requirements for updating design plans with ‘as constructed’ information, including annotations, or view an example.

'As constructed' information for open channels is relatively easy to obtain due to the accessibility, but can be dangerous due to slope and smoothness of surfaces, especially if the area is wet.