Effect of Adding Mooring Lines to the Truss Spar Platform

A contribution of adding one more set of mooring lines to an original truss spar was examined analytically. The equation of motion was solved in time domain by using Newmark Beta integration scheme. The wave forces were calculated using modified Morison equation. The mooring lines were modeled as nonlinear springs and their restoring forces were obtained by conducting quasi static analysis. A MATLAB program was used to conduct a dynamic analysis for two cases; first for the original structure with nine mooring lines and then for the same structure with additional six mooring lines. The numerical results showed that there was no significant changes in the dynamic responses of the spar. However, the additional mooring lines play a very important role when we consider the damages to the mooring lines.