PSI - Issue 44

Paola Sorrentino et al. / Procedia Structural Integrity 44 (2023) 1300–1307 Paola Sorrentino et al. / Structural Integrity Procedia 00 (2022) 000–000

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acceleration values, also exceeding 1g. This is strictly connected to the increasing in the number of seismic arrays for recording ground motions and the consequent availability of the number of strong motion data. The maximum acceleration value is 2.84g at 0.3s. The amplification zone extends up to the period of 1.10s. • The envelope of spectra by FEMA307, 1999 is comparable to Miyazaki’s envelope for periods between 1.2s and 2.2s. The maximum acceleration value is 3.70g at 0.2s. The amplification zone extends up to the period of 2.2s; in the de-amplification zone the envelope has high acceleration values, i.e. 0.5g at 2.4s. • The envelope of the spectra chosen by Miyazaki has a wider amplification zone if compared to the other sets, extending it to the period of 1.4s. For T > 2s, the acceleration values are high enough, still equal to 0.5g. The maximum acceleration value is 4.96g at 0.325s. For periods greater than 0.4s, this envelope shows the highest values, in comparison to the other sets. • The envelope of the spectra, based in the signal analyzed by Suzuki and Iervolino has higher values in the area of lower periods, with a maximum of 12.53g at 0.225s. On the contrary, for periods greater than 1.6s, it exhibits the lowest values, approximately equal to 0.20g. Furthermore, the amplification zone is not particularly wide, extending to period of 0.5s. • The envelope of spectra by De Luca and Guidi (2019) shows results comparable to the signal analyzed by Suzuki and Iervolino, with a maximum of 12.53g at 0.225s. The envelopes of the response displacement spectra (Figure 9b) increase with increasing period, with the exception of the envelope of the spectra in FEMA307, which decreases for periods between 2s and 2.8s. The maximum values range from 31.53cm to 180cm. In particular: • The envelope of pre 1971 spectra in Kelly (2001) has a maximum value of 31.53cm at the period of 3.0s, showing the lowest spectral displacements in comparison to the other sets. • The envelope of post 1971 spectra in Kelly (2001) exhibits a maximum value of 120cm at T= 3.0s; • The envelope of the spectra in FEMA307, 1999 has a maximum value of 115.07cm at the period of 2s. • The envelope of Miyazaki spectra shows values higher than the others, reaching its maximum of 180cm at the period of 2.6s. • The envelope of the spectra of the motions analyzed in Suzuki and Iervolino, 2017 exhibits lower values than the envelopes of FEMA307 and Miyazaki, although the high values in terms of acceleration. The maximum value is equal to 48.31 cm at the period of 1.9s. • The envelope of De Luca and Guidi (2019) spectra the highest value comparable to the one estimated by FEMA307 (1999), with a maximum of 72.42 cm at the period of 3.0 s.

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100 120 140 160 180 200

Trevor Kelly, 2001 - Pre 1971 Trevor Kelly, 2001 - Post 1971

Trevor Kelly, 2001 - Pre 1971 Trevor Kelly, 2001 - Post 1971

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FEMA307, 1999 Miyazaki, 2008

FEMA307, 1999 Miyazaki, 2008

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Suzuki and Iervolino, 2017 De Luca and Guidi, 2019

Suzuki and Iervolino, 2017 De Luca and Guidi, 2019

8

6

0 20 40 60 80

4 acceleration (g)

displacement (cm)

2

0

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

T (s)

T (s)

(a)

(b)

Figure 9. Envelope of spectral accelerations (a) and spectral displacements (b).

4. Conclusion

As result of the comparison among different sets of displacement and acceleration spectra, this paper shows the evolution of seismic demand in the last decades. The high values derived from the abovementioned envelops are