A NEW APPROACH FOR THE CALCULATION OF HYDRODYNAMIC FORCES ACTING ON LATTICE STEEL STRUCTURES.

Thewindforcesactingonthespacelatticestructures are determinedbyconsideringthesolidity ratio dictatedby ANSI/TIA-222-G (Steel AntennaTowers and AntennaSupportingStructures) technicalspecification. This governing methodology for the steady flow conditions was investigated for its applicability for unsteady flow conditions at marine environment. The relation between the solidity ratio and hydrodynamic forces was investigated by utilizing 5 models. The solidity ratio was identified as the ratio of the surface areas of wave ward structural members to the total surface area. ANSYS-Fluent software was used for evaluating the performances of models.Hydrodynamic wave forcesrepresentedbytheStoke?sSecondOrder wave theory. Morisonequationwasemployedtoobtain lateral wave forces. Artificial Neural Network (ANN) with the Levenberg-Marquardt optimization algorithm was used to determine the relation between hydrodynamic forces and various dimensionless parameters: solidity ratio (e),H/(gT2), d/(gT2), (zs/d), (t/T) and project area of sector (A). The performance of the evaluated ANN model indicated that, hydrodynamic forces can be obtained successfully by implementing the solidity ratio.