ASSEMBLY AND ERECTION - Prestressed Concrete Transmission Pole Structures - page 88

HANDLING
General
Handling a concrete pole at the structure site is one of the most critical
phases in the life of the structure. When lifting a pole clear of all supports,
attention must be paid to the manner in which it is lifted, because
the stress generated by a pole's own weight may be signifi cant. Poles
should be hauled, handled, and erected without incurring fl exural
cracks.
Pickup or Lifting Concrete Poles
Concrete poles can be designed to be lifted or erected with a one-point
pickup at the center of gravity or may require multiple-point pickups.
Designing for a one-point pickup without cracking may not be economi-
cal. The Manufacturer should mark the center of gravity and locations for
multipoint pickup.
A pickup is defi ned as lifting the pole from a horizontal position at rest
with a sling per the Manufacturer's instructions. The pickup may be a
total lift of the pole or may be a lift with the butt of the pole still resting
on the ground. The Manufacturer should provide the Purchaser with
lifting instructions for particular poles, and the Purchaser should transmit
these instructions to the construction personnel. The proper placement of
slings will allow either two-point handling or single-point erection
without any cracking.
The construction crew is responsible for the proper handling of poles
per the Manufacturer's instructions. Effi cient handling of the poles will
include unloading the pole (usually with a two-point pickup) at the struc-
ture site. The structure will be framed, and then using a one-point pickup
with the butt on the ground, the pole will be lifted to a vertical position
for placement over the hole for setting purposes (see Fig. 8-4).
FRAMING
General
Concrete poles generally are framed using through bolts (see Fig. 8-5).
Bolt lengths should be selected such that no less than 1/4 in. extends
beyond the nut or locknut. Bolts should be tightened in accordance with
the assembly drawings and Purchaser specifi cations. Care should be taken
to avoid over-tightening the bolts as this can cause longitudinal cracks in
a hollow concrete pole. The strength of the pole is suffi cient to withstand
a reasonable degree of bolt tightness, except near the ends of a hollow