Ass. Lect. Mohamed Adel Ahmed Elkasabgy :: Publications:

This paper presents the comparison between the full-scale vertical vibration response of a 9.0 m large-capacity single-helix pile and a driven steel pile of similar length, in order to qualify and quantify the large-capacity helical piles and driven piles’ dynamic performance. The test piles were close-ended piles with shaft outer diameter of 324 mm and helix diameter of 610 mm. Quadratic type harmonic load tests were conducted using five force intensities applied within frequency range that covered the resonance frequencies of the tested pile-soil-cap systems. The acceleration at the level of the centre of gravity of the pile cap system was recorded. The dynamic and static properties of the site soils were determined using the conventional soil boring and testing methods and the seismic cone penetration tests. The current study compares the field observations against the theoretical predictions and provides an insight into the role of pile-soil interaction in theoretically matching the field observations. The effects of soil nonlinearity, soil separation, pile slippage, and the effect of the boundary zone concept were considered in the simulation process and the stiffness and damping parameters of the test piles were obtained. The findings from this project are considered to be useful in the design and analysis of piles under similar geometrical and material conditions as well as validating the adequacy of the existing theoretical formulations for analysing the dynamic response of helical piles