UPLIFT CAPACITY ANALYSIS OF ANCHOR FOUNDATION FOR TRANSMISSION TOWER ON SLOPE CREST

The conventional formula, the so-called logarithmic spiral equation, for uplift capacity of enlarged base anchor foundation for transmission towers is capable of evaluating accurately the uplift capacity in horizontal grounds, and thus is widely used in engineering practice. However, in the evaluation of the uplift capacity in inclined grounds or other complex embedment conditions, control of minimum embedment depth or conical soil volume to insure a sufficient overburden weight, or some empirical approach, is employed. This paper examines the uplift capacity of anchor foundation embedded in a slope crest. For this purpose, the three-dimensional elastoplastic finite element analysis is utilized. The effect of the distance from the edge of slope crest on the uplift capacity is investigated for different slope angles. The analysis result shows that, if the edge distance is less than a certain value, the uplift capacity decreases significantly with a decrease in the edge distance. It is also found that the uplift capacity decreases nonlinearly with an increase in the slope angles, and it shows a larger decrease as the edge distance is smaller.