Nonlinear Seismic Response of Articulated Offshore Tower

Abstract

The seismic response of articulated offshore tower has been investigated by the spectral analysis
method which is based on the principle of random vibration, where seismic excitation is assumed to
be a broadband stationary process. The nonlinear dynamic eqliation of motion is derived using
Lagrangian approgch and the solution is obtained by Newmark's P integration scheme. The present
study includes nonlinearities associated due to variable submergence, drag force, Coulomb damping,
variable buoyancy, and added m sal ong with the geonmrical nonlinearities of the system. The study
includes the joint occurrence of waves and seismic fofces together with the current under random sea
state. A parametric study has been conducted to investigate the relative importance of the seismic
response in comparison to the response due to wave forces.