Effect of damping on response of pile group
Research Publishing Services
Faculty of Health, Engineering and Science
School of Engineering
In the present study, dynamic analysis of a pile group in 2 × 2 arrangement is carried out by considering the three dimensional nature of the soil-pile system. Piles and soil are modeled using three-dimensional finite element techniques treating them as linear elastic elements. Pile and pile cap are modelled using 20 node element considering the bending aspect whereas the surrounding soil is modelled with 8 node element. The interface of soil and pile has been accounted for by incorporating 16 node interface elements in the modelling. At the transition between 20 node and 8 node elements, appropriate 12 and 9 node elements are used which were derived using degradation technique from 20 node elements. The special type of transmitting boundary using the Kelvin element is used to transfer the propagating waves from near field to the far field. Individual piles in a group are assumed to be connected monolithic with the pile cap. Three types of damping are considered to examine their effect on the dynamic response as mass proportional, stiffness proportional and Rayleigh damping. Results are also compared with the case of zero damping. Results are presented in non-dimensional form in the form of maximum deflection frequency response curve. It is observed that the effect of damping is significant on the amplitudes of vibration whereas small shift in the fundamental frequency is noticed.