Procedure For Pole Manufacturing
All reinforcement and duct shall be accurately placed and maintained in position during manufacturing. Grouping of high tensile wires may be permitted as long as the diameter of the wire is between 3mm and 5mm.
For post tensioned poles, the relative position of wires in a cables , whether curved or straight shall be accurately maintained by suitable means to ensure the free flow of gout.
For prestressed pretension system, all wire shall be accurately stretched with uniform prestress in each wire. Each wire or group of wire shall be anchored positively during casting. Care shall be taken to see that the anchorages do not yield before the concrete attains the necessarily strengths.
All post tensioned work duct shall be grouted using any suitable grouting techniques.
In pre-tensioned work, the cover of concrete measure from the outside of the presetressing tendon shall be atleast 30mm or the size of the cable or bar whichever is bigger.
In the case of single wire used in pretensioned system , the minimum clear spacing shall be less than greater of the following.
Three times of diameter of the wire
One and one-third 11/3 times the maximum size of aggregate used.
In the case of cables or larges bars, the minimum clear spacing (measured between sheath/ducts , wherever used) shall not be less than greater of the following
The high tensile steel wire or bar shall be continuous over the entire length of the tendon. Welding shall not be allowed in any case.
5mm plus maximum size of aggregate.
Maximum size of cables or bars
Welding and lapping of reinforcement
Earthing shall be provided by one of the following means
By having a length of 25×3 mm copper strip or equivalent bare copper cable
The concrete shall be covered with a layer of shaking and canvas hessian or similar absorbent material and kept constantly wet up the time when the strength of concrete is at lest equal to the minimum strength of at transfer of prestress.
During manufacturing, daily test on concrete cubes shall be carried out till the concrete achieves the required strength at transfer. Thereafter the test on concrete shall be carried out as detailed in IS 1343. The manufacturer shall supply when required by the purchaser or his representative.If the purchaser so desires, the manufacturer supplied cubes shall be tested in accordance with IS 456.
By providing two holes of suitable dimensions 215mm from top and 150mm below ground level to enable 25mmx3mm copper strip or equivalent bare copper cable to be taken from top hole to the bottom through the center hole. During manufacturing, sufficient number of holes shall be provided in the poles for the attachment of cross arms and other equipment.
4 mm dia galvanized iron wire embedded in concrete during manufacture and the ends of the strip or cable left projecting from the pole to a length of 50mm at 215 mm from top and 150 mm below ground level.
If desired by the purchaser, to facilitate handling of poles during transport and erection, an eyehook may be provided in every pole at 100mm below ground level on the face of the pole so as to utilize the maximum flexural strength of the section during handling.