Issue 51

D. Vasconcelos et alii, Frattura ed Integrità Strutturale, 51 (2020) 24-44; DOI: 10.3221/IGF-ESIS.51.03 42 Original Foundation Reinforced Foundation Point Stress Value Point Stress Value V1 376.87 MPa A2 21 MPa L1 294 MPa B2 29 MPa N1 336.7 MPa C2 32 MPa Transient analysis at wind speeds of 24 m s -1 Fig. 27 shows the global model analysis at wind speeds of 24 m s -1 and Fig. 28 shows the results of the BC analysis at the same speed. The highest stress for the springs formulation is 113 MPa, yielding a safety coefficient of 3.11. For the displacements formulation, the highest stress verified is 210 MPa, achieving a safety coefficient of 1.668. Once again, the influence of singularities should be carefully analysed in future works. Table 8: Mode description and respective frequency. Properties Original Structure Final Structure Steel Mass [Tonnes] 3 852 9 543 Overall Ballast’s Water Mass [Tonnes] 9 621 3 930 Fundamental Frequency [Hz] 0.278 0.6896 Lower Safety Coefficient at 11.4 m s -1 0.032 1.67 Lower Safety Coefficient at 24 m s -1 Analysis not performed 1.668 Figure 27 : Global model analysis with springs formulation. Units in Pascal. Figure 28 : BC analysis with the displacements formulation. Units in Pascal. Table 7 : Comparison of results between points of interest of the original foundation analysis and the reinforced foundation analysis, both using the springs formulation at 11.4 m s -1 .