Centrifuge modelling of tower structures on saturated sands subjected to earthquake perturbations

The dynamic behaviour of a tower structure founded on a saturated sand bed subjected to model earthquakes was investigated using the bumpy road-shaking system of the Cambridge centrifuge. Excess pore pressure was generated and effective stress reduced. When the initial natural frequency of the tower–soil system exceeded the driving frequency of the earthquake, the reduction in effective stress caused a degradation in the soil stiffness and a lowering of the natural frequency. The generation of excess pore pressure caused a jump in the natural frequency of the tower-soil system to a discrete frequency at which the energy of the earthquake was concentrated. When the initial natural frequency was either equal to or less than the driving frequency of the earthquake, the excess pore pressure did not cause any change in the natural frequency of the tower–soil system. Le comportement dynamique de la structure d'une tour fondee sur un lit de sable sature et soumise a des simulations seismiques a ete etudie a l'ai...