Lateral Capacity of Helical Piles in Clays

Abstract

In this paper, the behavior of helical piles under lateral loads in clayey soils is examined through an experimental investigation on model piles. Tests were conducted on rigid helical piles with different numbers of plates. Model anchors were made of 13.8 mm diameter mild steel shafts to which mild steel plates of 33 mm diameter were welded. For comparison, a single straight shaft with a diameter of 13.8 mm was also tested. Test results revealed that the lateral capacity of helical piles is greater than that of straight shaft piles. A simple theoretical model is suggested to estimate the lateral capacity of rigid helical piles. The theoretical model suggested incorporates lateral resistance of the soil on the shaft, bearing resistance on the bottom of the helical plate, uplift resistance on the top of the helical plate, and frictional resistance on the surface of the helical plate. The validity of this model is examined.