Stability analysis of concrete gravity basestructures in rocking motion under wave effect

Given the worldwide industry progress in the construction of massive concrete structures, it would be a good idea to use concrete gravity base structures (GBS).In this regard, better understanding of thesestructuresregardingtheiradvantages and disadvantages in offshore areas seems necessary.The present study employed MacCammy-Fuchs method, which is based on the size of the structure to the wavelength and the range of Keulegan-Carpenter number; in this method, diffraction theory and Bessel functions are used to compute the velocity potential function and consequently compute the hydrodynamic pressure on the components of the structure.The results of this study with regard to the harmonic dynamic response of the rocking motion of the platform under wave loads revealed that (i) the computed torque value converges to a definite value by decreasing the size of elements,and (ii) Bessel functions can be represented by amplitude and phase functions which have identical performance.The time-history response of the gravitybase structure, and the amplitudechanges of rocking motion relative to frequency and the height of the waves are other results obtained in this study. Finally, the stability index of the GBS shows that the platform is within safe limits.