Effect of soil-pile cap interaction on the dynamic response of rotary-machine foundations

Muthanna Journal of Engineering and Technology

Volume (3), Issue (2), Year (30 December 2015), Pages (42-49)


Research Article By:

Raid R. Al-Omari, Hussein Mandeel Ashour and Basim Jabbar Abbas

Corresponding author E-mail: tosharaid@yahoo.com


This paper investigates the effect of soil-pile cap interaction on the dynamic behavior of the soil-pile system under vibrations. Vertical vibration tests were conducted using experimental models of pile footings embedded in a finite dry sand layer. The pile footings consist of two groups of circular piles with spacing/diameter (S/d) ratio equals to 5; the length/diameter (L/d) ratio for first group was 13.3 and for the second was 20. Each group includes models with different number of piles. A physical model made of steel box of dimensions of 700 × 700 mm and 800 mm in height was used for accommodation the test model. In order to study the effect of cap interaction, the first tests were conducted where a gap was left between the caps and sand surface as reference, and the second tests all caps in contact with sand surface. The maximum displacement amplitudes and the corresponding resonant frequencies of the experimental system were measured using vibration meter and accelometer fixed on the top of the pile cap. The results of both groups indicated that the pile cap interaction significantly increases the vertical amplitudes and increases slightly the resonant frequencies in different proportions.

Keywords: Vertical displacement amplitude, resonant frequency, length of pile/diameter ratio (L/d), spacing of piles/diameter ratio (S/d), pile groups.

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