Transmission Pole Foundations: Alternate Design Methods for Direct-Embedded Round, Wood Transmission Poles

Although close attention is paid to the design of transmission poles, many times the design of the foundation is left up to a "rule of thumb" method. Reliable and established methods for analyzing laterally loaded piles have been incorporated into the current study to calculate the required depth of embedment for transmission poles, and the results are compared to the current methods. The results show that the current methods for determining embedment depths for direct-embedded transmission poles significantly underestimate or overestimate the required embedment depth depending on the soil conditions. Recommendations are made for alternate design methods for transmission pole foundations. A case study is presented where direct-embedded wood transmission poles fell over due to inadequate foundation design. The results of the case study are compared to the methods presented in this paper. It is concluded that the alternate design methods will generate more accurate results than the current methods.