PSI- Issue 9

Riccardo Fincato et al. / Procedia Structural Integrity 9 (2018) 136–150 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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coupling of the elastoplastic and ductile damage internal variables offers a better agreement with the experimental data, especially if the tangential inelastic stretch contribution is considered. However, the graph in Figure 5b can give just a qualitative indication on the structural response since the area of the hysteresis loops is subjected to some imprecisions such as the impossibility to control experimentally the exact maximum (positive or negative) prescribed displacements. As a general tendency, the blue solid line can catch quite realistically the absorbed peak and the post peak behavior of the pier.

a)

b)

c)

d)

Figure 5 a) Envelope of the positive side, b) energy absorption per cycle for the loading sequence of Figure 2b, c9 radial displacement around the base of the pier column, d) damage evolution (centroid) for three points at the base of the steel pier.

As an additional check, Figure 5c compares the numerical and experimental lateral displacement at the unloading point near the maximum loading per loop (i.e. , 2 , , 9 y y y         ). The numerical results are in good agreement with the real radial displacements reported with red marks for the 3 y   and 6 y   loops reported in Van Do et al. (2014) and Gao et al. (1998). The maximum radial displacements take place at around 120 mm from the base of the pier, which seems to be slightly lower than the experimental evidence. However, similar numerical results were obtained by Van Do et al. (2014) and Gao et al. (1998) who investigated the same study case. One of the reasons for the discrepancy between the experimental and FE results might be due to the influence of the welded area at the base of the column, which was simulated as a pure ‘encastre’ in the numerical modeling.