Specification Part 3 - Road & Bridge Works - Urban Administration ...

11. Excavation in marshes shall begin at one end and proceed in one direction across the entire
marsh immediately ahead of backfilling to ensure complete removal or displacement of muck.
12. For widening of existing pavement, the existing shoulders shall be removed to their full width
and upto sub-grade level to enable proper compaction in the widened portions.
13. Excavation of structure & Preparation of foundation shall be done Clause 304.
14. The horizontal alignment should be reckoned with respect to the centre line of the carriageway
as shown on the drawings. The edges of the roadway as constructed should be correct within a
tolerance limit of (±) 30 mm in plain and rolling terrain and (±) 50 mm in hilly terrain.
15. No point on the slopes shall vary from the designated slopes by more than 150 mm measured
at right angles to the slope (300 mm in case of rock excavation).
16. Do not remove the bench marks, reference lines, stakes etc. used for setting out of works
without informing the Engineer.
17. Do not let the loose material/debris remain on the slopes of cutting/ along the road.
18. Do not allow the rock to protrude above the formation level at any point.
19. Do not stack stone boulders on embankment to ensure free flow of traffic especially on hill
roads.
20. Do not throw the debris on the valley side to avoid damage to property/ environment.
21. Take precautions against soil erosion, water pollution, etc. and for preservation of existing trees,
drains, sewers, pipes, conduits, poles or any other structures.
22. Remove water, if met during excavation, from springs, seepage or other causes, by suitable
diversions, pumping, or bailing out to keep the excavation dry.
23. Rocks and boulders, which are likely to cause differential settlement should be removed to the
extent of 500 mm below the formation level.
24. Take precautions during construction to ensure stability and safety of slopes.
25. Near Town trenches and foundation pits should be securely fenced and provided with caution
signs in the interest of public safety.
26. Ensure that unsuitable and surplus material from cuttings is disposed of as directed by the
Engineer.
27. Ensure that proper longitudinal gradients as per drawings have been achieved.
28. Do not remove the bench marks, reference lines, stakes etc. used for setting out of works
without informing the Engineer.
29. Do not let the loose material/ debris remain on the slopes of cutting/ along the road.
30. Do not allow the rock to protrude above the formation level at any point.
31. Do not stack stone boulders on embankment to ensure free flow of traffic especially on hill
roads.
32. Do not throw the debris on the valley side to avoid damage to property/ environment.
305 EMABANKMENT CONSTRUCTION
305.1 General
305.1.1 All embankments sub-grades, earthen shoulders and miscellaneous backfills shall be
constructed with approved material obtained from approved source, including material from roadway
and drain excavation, borrow pits or other sources in accordance with the requirements of these
specifications and in conformity with the lines, grades, and cross- sections shown on the approved
drawings or as directed by the Engineer-in-charge.
305.2 Materials and General Requirements
305.2.1 Physical requirements
305.2.1.1 The materials used in embankments, subgrades, earthen shoulders and miscellaneous
backfills shall be free of logs, stumps, roots, rubbish or any other ingredient likely to deteriorate or affect
the stability of the embankment/sub-grade. The material used in embankments, subgrades, earthen
shoulders and miscellaneous backfills shall be soil, moorum, gravel, pond ash, a mixture of these or any
other material approved by the Engineer-in-charge. The use of pond ash as fill material shall be
mandatory in road/ flyover embankment construction in the areas where pond ash is available in
adequate quantities within economical viable lead in accordance with the guidelines of IRC: SP: 58-
2001 unless it is not considered viable by the Chief Engineer.
305.2.1.2 Expansive clay exhibiting marked swell and shrinkage properties (“free swelling index”
exceeding 50 percent when tested as per IS: 2720 – Part 40) shall not be used as a fill material. Where
an expansive clay having “free swelling index” value less than 50 percent is used as a fill material,
subgrade and top 500 mm portion of the embankment just below sub-grade shall be non-expansive in