BID Document for Guest House with Boundary Wall.pdf - Integrated ...

the work is in progress, the Contractor shall provided and use warning and / or traffic signs / lights or lanterns,
barricades, fencing, watchman, etc.
2.1.5 Extra Depth and Clearance:
At points where the contour of the earth may require extra depth according to customary good pipeline
practice, or where a deep trench is required at the approaches to crossings of roadways, sewer line, Contractor
shall excavate such additional depth as may necessary after obtaining permission from the EIC.
Contractor shall excavate to additional depth as directed by the Engineer-In-Charge, where the pipeline
approaches and crosses other pipelines, sewers, drain pipes, telephone conduits and other underground
structures and specific low lying area so that the pipeline may be laid with at least 50 centimeters free
clearance from the obstacle or as specified in the drawings, or such greater minimum distances as may be
required. No pipeline shall be laid so as to be in contact with any electrical supply line, telegraph line, drain,
sewer or connection work.
Where the pipeline crosses areas, whose basement specifically require greater than normal depths of cover the
trench shall be excavated to extra depth in accordance with the Right of Way agreement or as required.
Contractor shall excavate all such additional depths to maintain the depth of earth cushion beyond 1.20 mtr as
may be necessary for satisfactory completion of the work.
Clearance on one side or the other of any interfering structures shall be determined on the field in accordance
with the circumstances of each case with the provision that the line shall be laid as directed by the Engineer-
In-Charge. Temporary under passing supports and other protective devices necessary to keep interfering
structures unaffected, shall be provided by the Contractor and shall be of such design so as to ensure against
their possible failure.
2.1.6 Finish of Trench:
The employer intends that there shall be a minimum of hand guarding of the trench bottom However, to
achieve this, Contractor shall have to dig as square a bottom of the trench as possible with the equipment. This
in part can be obtained by adjusting and adopting the crumbling shoe and digging teeth of the trenching
machines and by use of a drag behind the trenching machines. Contractor shall do hand work in the trench if
necessary to free the bottom of the trench from loose rock and hard soil and to trim protruding roots from the
bottom and side walls of the trench. However, the Contractor has the liberty to adopt any procedure according
to site condition with due approval of the Engineer-In-Charge. Trench compactor should be used to compact
the bed.
2.1.7 Padding:
In all cases where rock or gravel is encountered in the bottom of trench, trench padding shall be provided to
safeguard the pipe coating. The extent of trench padding (length) shall be decided by the Engineer-In-Charge.
The thickness of the compacted padding shall not be less than 150 mm. In those areas that are to be padded
the trench shall be at least 150 mm deeper than otherwise required, and evenly and sufficiently padded to keep
the pipe, when in place at least 150 mm above the bottom of excavated trench. Padding materials shall be sand
containing no gravel, rock, or lumps of hard soil.
2.1.8 Protection of Trench:
Contractor shall keep the trench in good conditions until the pipe is laid. All type of safety measures for
excavation work shall be taken and maintained as required. The Contractor shall provide, install and operate
all the necessary pumping machineries, piping appliances and equipments and supply fuel, etc. to keep trench
reasonably free from any water during excavation.
2.1.9 Protection Of Underground Utilities:
Contractor shall obtain plans and full details of all existing and planed underground services from the EIC and
shall follow plans & co-ordinates closely at all time during the performance of work. Contractor shall be
responsible for action and protection of all underground lines and structures. In special locations, the use of
trenching machine / backhoe may result in damage of property and subsurface structures likely to be
encountered during excavation. At such places, Contractor shall excavate the trench manually to same
specifications.
Where the pipeline crosses other underground utilities / structures, Contractor shall first manually excavate to
a depth the utilities / structures are located.
Temporary underpinning, or any other type of supports and other protective devices necessary to keep the
interfering structure intact shall be provided by Contractor to ensure against their possible failure.
In locations, where the pipeline has to be laid more or less parallel to an existing pipeline, cable and / or other
utilities in the right of way Contractor shall perform the work to the satisfaction of the Authority of the
existing pipeline / cable / utility. In such locations Contractor shall perform work in such way that even under
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