The pre stressing steel wire including those used as intentioned wire shall confirm to IS: 1785(part-1)/1966, ISS: 1785(part 2)1967 or 6003/1970 in case of indented wire. The wire shall be of 4 mm dia with a guarantee ultimate’s strength of 175kg/mm square.The concretes mixture shall be designed to the requirement laid down to controlled concrete in ISS: 1343/1980 and ISS: 456/1973. Cubes strengths at 20 days shall not be less than 420 kg/mm2. The maximum compressive stress in concrete at the time of transfer of pre stressed shall not exceed 0.8 times. The cube strength and concrete strength at transfer shall not be less than half the 28 days strength i.e. 420 X 0.5 = 210 kgs/mm2. The concrete shall be mechanically compacted by shuttering vibrators.Poles shall have the factor of safety 1.0 against first crack load and not less than 2.3 against failure for loads applied at .06 meter from top with 1.6 meter of pole inside the ground. The guaranteed minimum ultimate transverse load shall not be less than 500 kgs.The ultimate moment capacity in the longitudinal direction should be at least one fourth of that in the transverse direction.
Pole shall be rectangular in cross section. The top section shall be 145 MM X 90MM and bottom section 290 mm X 90 mm total length of 8 meters, over all weight of 360 kgs. Each pole shall be provided with 18 mm dia through holes suitable for 16 mm disc bolt at the following distance from the top along the minor axis in case of poles shall be used on L.T lines.Each pole shall be provided with pre stressing steel wire of 4MM diameter with guaranteed ultimate strength of 175 kgs/mm2, nos. as tensioned wire and 2 numbers with pre stressed wires.
Along the minor of 8 meter 200 kg work load from top and 2nd hole at 200MM from top.
Along the minor axis 5 holes. 1st hole at 75 MM from top. 2nd hole at 375 MM from top. 3nd hole at 675 MM from top. 4th hole at 975 MM from top. 5th hole at 1275 MM from top. Both sides of the holes as indicated above shall be provided in each pole.
PSC poles shall comply with the recommendation of REC as per the specification 15/1979 (with latest amendment) excepts where the conflicts specific requirement, with the above REC specification, the pole shall comply with the relevant provisions made in the following ISS specification.
Each Pole Shall Be Embossed Or Engraved With
Each pole should be provided for earthing 8 SWG wire embedded in concrete during manufacturing in such a way that the end of the wire are left projecting from the pole to a length of 50 mm at 250 mm from top and 150 mm below ground level. i.e. 1350 mm from bottom end. The earthing wire so provided shall not be allowed to come in contact with pre stressing wires. The above provision shall be made as per the drawing. Further each pole shall be provided with M.S stirrups as per ISS 432/1966 with anneals wire of ultimate strength of 32 kg/mm square and 4 mm M.S wire ten in numbers spread throughout the length at suitable spacing. Permissible tolerance in plighting shall fully confirm to relevant provision of ISS: 1342/1980 and ISS: 1678/1978 and the latest publications.