Abstract
This paper provides general theory of nondeterministic analysis of offshore structures subjected to the wave and the current simultaneously. The equations of motion are derived and nonlinear drag force in hydrodynamic force is presented The dynamic wave forces and the structural response to them are assumed to have zero-mean, Gaussian characteristics when suitably linearized. The linearization an the drag force with current velocity is carried out using the least square method The damping on the generalized coordinate is diagonalized and the structural responses are calculated by the random vibration approach. It is suggested that the current velocity has significant contributions on the wave force evaluation and the dynamic response of the offshore structures.
