Desarrollo de una metodología para el diseño de estado último de estructuras offshore fijas.

Abstract

This work deals with the development of a methodology for ultimate limit state (ULS) design of fixed offshore structures under extreme environmental conditions. For this, design codes, scientific papers, and state-of-the-art computer codes were used. A hydrodynamic numerical model was created in Ansys AQWA. This model allows for computation of hydrodynamic loading on an offshore tower. These loads are transferred to the finite element code Ansys Mechanical APDL. Based on the nominal stresses on the structural members, critical joints of the tower are identified. Thus, stresses in these joints can be corrected and analyzed. The methodology is applied to assess critical joints in the tower by considering the design significant wave height (Hs) obtained from a covariate (including directional effects) and non-covariate (using combined wave spectra) extreme value analysis (EVA). This is done for two offshore locations, one in the North Atlantic Ocean and another in the Arabian Sea. For the North Atlantic Ocean, the stresses in critical joints of the tower can be about 20% larger than those obtained from non-covariate EVA. These findings are important for future calibration of load factors of offshore standards to allow more robust and reliable designs of fixed offshore structures