SAMPLE PURCHASER TECHNICAL SPECIFICATIONS FOR SPUN-CAST PRESTRESSED CONCRETE POLES FOR TRANSMISSION AND DISTRIBUTION STRUCTURES - Prestressed Concrete Transmission Pole Structures - page 126

6.2 Prestressing Steel Tendons

6.2.1 Specifi cations : The prestressing steel tendons shall be stress relieved
seven-wire strand conforming to the latest revision of ASTM A-416,
“Specifi cation for Uncoated Seven-Wire Stress-Relieved Strand for
Prestressed Concrete,” for both normal and low relaxation strand.
6.2.2 Welding : Welding of the prestressed steel is not allowed.

6.3 Inserts
All inserts shall be manufactured of a noncorrosive material.

6.4 Spiral Wire

All poles shall contain spiral steel reinforcement throughout the entire
pole length. The minimum diameter of the spiral wire shall be 3/16 in. and
conform to ASTM A-82. The spacing shall conform to the following:

6.4.1 Pitch spacing : For a distance of 3 ft from the tip and butt of the
pole, spirals shall be spaced a maximum of 1-3/4 in. on center but
no less than 1-1/4 in.
6.4.2 Torsional loads : If torsional loads are encountered, the spiral
spacing shall be adjusted, if necessary, to provide suffi cient rein-
forcement in accordance with the latest version of ACI 318.
6.4.3 Groundline and embedded portion of the pole : Closer spiral spacing
may be required in the region between 3 ft above groundline to the
pole butt to adequately resist the increased shear encountered in
developing the resisting soil pressure and near guy wire or dead-end
attachments where high shear concentration occurs.
6.4.4 Maximum spacing : The maximum center to center spacing (pitch)
throughout the remainder of the pole shall be such that the following
condition is satisfi ed:

A v (F v / s ) ≥ 0.48

where A v is the area of one spiral leg in square inches, F v is the design
yield stress of the grade of steel used in ksi ( ≤ 60 ksi), and s is the

center to center spacing of the spirals in inches.
In no case shall the spacing s exceed 4 in.

7. TESTING FOR CONCRETE STRENGTH

The Manufacturer shall, at company expense, take at least eight repre-
sentative cylinders of each day's pour and test as follows: one at release,
two at seven days, two at 14 days, and three at 28 days. A copy of the test
reports shall be furnished to the Purchaser upon request.