The shear strength of beam-column members is becoming able to be estimated accurately by theoretical methods through many previous studies. For concrete piles however, no satisfactory method to predict the shear strength of the piles has been established. In this paper, the failure mechanism of the PHC piles with large diameter is considered firstly by means of the finite element analysis. Secondary, the estimation formula for predicting the ultimate strength of the piles is proposed based on the upper bound theorem of the limit analysis from the previous consideration.
