job site. The connection to city services can average between 10 feet and 20 feet depending on the
location in the city.
Storm drain and sewer pipe are "gravity" systems and not under pressure. Therefore the pipe must have
a continuous slope to the point of connection at the city services. Keeping this slope and avoiding
conflicts with each other and other utilities is a difficult task.
Branch lines of the mains serving the buildings can be as shallow as 2 feet to 10 feet depending on the
proximity of the branch to the building and / or main line. Tis is where many of the conflicts with other
utilities occur.
Keys to Watch for: Coordination with other utilities, installing the deepest first, bedding material type,
backfill material, compaction of backfill, removal of spoils, return to original grade, manhole types,
compaction at manholes, encroachment permits, connection fees, early material approval.
Safety Issues: Trench sloping or shoring, confined space requirements, spoils placement, location of
ladders, swing radius of excavator, safety belts for operator, back up bell for equipment
direction to the excavator. The type and size of excavator or backhoe will be determined by the depth and
size of pipe to be installed. The excavator will usually dig a distance ahead to allow a crew to lay pipe
continuously. Sand bedding material is placed prior to pipe installation
5,6,7) Pipe is laid along the trench to stage for installation. Pictures 5 and 6 show pipe layed out along
open field trenching areas. Picture 7 shows a later line to a building. The building connection is just
above the CMU wall at the bottom center o the picture
8,9,10) Sand is then backfilled to just above the pipe. Use of sand reduces the potential of damage to
the pipe by rocks in native material. Sand bedding and backfill is compacted by hand using a "whacker"
11,12) Pipes are stubbed to the manholes
13) The base of the manhole is poured. The holes for the pipe inlets can be seen in this picture. The
pipes have been covered by sand.
14,15,16) Steel forms are set for the installation of manholes in some cases and precast is used on
other cases.
17,18) Precast rings are shown prior to installation and then shown set in place
19,20) An excavator with a compaction wheel attachment backfills and compacts the trench in lifts
ranging from 1 to 2 feet until the soil has returned to the original grade. A large loader then regrades the
entire are to complete the final grade process
21,22) The final two pictures show the soil back to grade with pipe stubs where the building
underground plumbing will be connected.
Excavation per day -
L.F. of pipe per day -
L.F. of backfill per day -
Manholes per day -
6 to 10 Feet:
Excavation per day -
L.F. of pipe per day -
L.F. of backfill per day -
Manholes per day -
as legal advice and does not represent advice with regard to specific practices or undertakings and construction reference.com shall not be responsible
for any damages of any kind including direct, indirect, incidental, special or consequential damages that may arise out of or result from reliance on the
information provided on this web site.
