Study on Uplift Resistance of Screwed Steel Pile

A screwed steel pipe pile exerts a huge resistance at the lower end against an uplifting load owing to the anchoring effect of the spiral wing provided at the pile end. Uplift tests of reduced-scale screwed pipe piles using purpose-made model test equipment clarified the relationship between pile diameter, wing diameter, pile-end depth and the uplift resistance at the pile end. Visible tests and earth pressure measurement with reduced-scale piles carried out after the above disclosed the soil movement and earth pressure near the pile end at pile driving and uplifting. Based on these results, the shape of the shear fracture zone of soil that brought about the uplift resistance was estimated.