STRUCTURAL CONFIGURATIONS AND POLE APPLICATIONS - Prestressed Concrete Transmission Pole Structures - page 8

Fig. 1-7. Two-pole braced guyed dead-end structure
Source: Photograph courtesy of Valmont Newmark. Reproduced with
permission.
loading from long span, large line angle, or dead-end applications exceeds
the cantilever capacity of concrete poles. The structures are guyed at some
or all of the conductor positions depending on the loading. This approach,
however, is becoming more diffi cult to use in urban and suburban areas
because of the cost and diffi culty of obtaining guy easements.
The braced H-frame is a common structure. The H-frame is often used
for long, cross-country transmission lines. Frame action enables this struc-
ture to support large horizontal and vertical loads, resulting in longer
span lengths and larger wire size than single-pole, cantilever structures.
These structures can also be designed to carry signifi cant longitudinal
loading by cantilever or guying. H-frame structures are not typically used
in urban and suburban areas, because they require a wide right-of-way
corridor and create a large footprint.
Combinations of cantilevered, guyed, and framed structures can be
used to optimize the benefi ts of each type. Two examples of combined
structures are guyed H-frame structures and dead-end structures that are
guyed in one direction and self-supporting in the other direction. Guyed
H-frames can be used to provide increased longitudinal capacity as an