ASD/LRFD Manual - American Wood Council

34 M6: ROUND TIMBER POLES AND PILES
M6.1 General
Product Information
Timber poles are used extensively in post-frame construction
and are also used architecturally. This Chapter is
not for use with poles used in the support of utility lines.
Timber piles are generally used as part of foundation
systems.
Timber poles and piles offer many advantages relative
to competing materials. As with other wood products,
timber poles and piles offer the unique advantage of being
the only major construction material that is a renewable
resource.
Common Uses
Timber poles are used extensively in post-frame construction
and are also used architecturally. This Chapter
is not for use with poles used in the support of utility
lines. Timber piles are generally used as part of foundation
systems.
Timber poles and piles offer many advantages relative
to competing materials. As with other wood products,
timber poles and piles offer the unique advantage of being
the only major construction material that is a renewable
resource.
Availability
Timber piles are typically available in four species:
Pacific Coast Douglas-fir, southern pine, red oak, and red
pine. However, local pile suppliers should be contacted
because availability is dependent upon geographic location.
Timber poles are supplied to the utility industry in
a variety of grades and species. Because these poles are
graded according to ANSI 05.1, Specifications and Dimensions
for Wood Poles, they must be regraded according to
ASTM D3200 if they are to be used with the NDS.
M6.2 Reference Design Values
General
The tables in NDS Chapter 6 provide reference design
values for timber pole and pile members. These reference
design values are used when manual calculation of member
strength is required and shall be used in conjunction with
adjustment factors specified in NDS Chapter 6.
Pole Reference Design Values
Reference design values for poles are provided in
NDS Table 6B. These values, with the exception of F c ,
are applicable for all locations in the pole. The F c values
are for the tip of the pole and can be increased for Pacific
Coast Douglas-fir and southern pine poles in accordance
with NDS 6.3.9.
Reference design values are applicable for wet exposure
and for poles treated with a steam conditioning or
Boultonizing process. For poles that are not treated, or are
air-dried or kiln-dried prior to treating, the factors in NDS
6.3.5 shall be applied.
Pile Reference Design Values
Reference design values for piles are provided in
NDS Table 6A. These values, with the exception of F c ,
are applicable at any location along the length of the pile.
The tabulated F c values for Pacific Coast Douglas-fir and
southern pine may be increased for locations other than
the tip as provided by NDS 6.3.9.
Reference design values are applicable for wet exposures.
These tabulated values are given for air-dried piles
treated with a preservative using a steam conditioning or
Boultonizing process. For piles that are not treated, or are
air-dried or kiln-dried prior to treating, the factors in NDS
6.3.5 shall be applied.
American Wood Council