2012 ASD/LRFD Manual for Engineered Wood Construction

24 M6: ROUND TIMBER POLES AND PILESM6.1 GeneralProduct InformationTimber poles and piles offer many advantages relativeto competing materials. As with other wood products,timber poles and piles offer the unique advantage of beingthe only major construction material that is a renewableresource.Common UsesTimber poles are used extensively in post-frame constructionand are also used architecturally. This Chapteris not for use with poles used in the support of utilitylines. Timber piles are generally used as part of foundationsystems.AvailabilityTimber poles are supplied to the utility industry ina variety of grades and species. Because these poles aregraded according to ANSI 05.1, Specifications and Dimensionsfor Wood Poles, they must be regraded according toASTM D3200 if they are to be used with the NDS.Timber piles are typically available in three species:Pacific Coast Douglas-fir, southern pine, and red pine.However, local pile suppliers should be contacted becauseavailability is dependent upon geographic location.M6.2 Reference Design ValuesGeneralThe tables in the NDS Supplement provide referencedesign values for timber pole and pile members. These referencedesign values are used when manual calculation ofmember strength is required and shall be used in conjunctionwith adjustment factors specified in NDS Chapter 6.These values, with the exception of F c , are applicable forall locations in the pole or pile. The F c values can be increasedat other locations in accordance with NDS 6.3.9.Reference design values for poles and piles are basedon air dried conditioning. Kiln-drying, steam conditioning,or boultonizing prior to treatment will have the effect ofreducing the reference design value per NDS 6.3.5.Pole and Pile Reference DesignValuesReference design values for piles and poles are providedin NDS Supplement Tables 6A and 6B, respectively.AMERICAN WOOD COUNCIL