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

1303

4

140

4

1987, Whittier Narrows - Mt Wilson CIT Seis Sta 1992, Big Bear - Civic Center Grounds 1988, Spitak - Gukasyan 1989, Loma Prieta - Corralitos 1994, Northridge - LA Century City 1979, Imperial Valley - Array 7 Envelope

1987, Whittier Narrows - Mt Wilson CIT Seis Sta 1992, Big Bear - Civic Center Grounds 1988, Spitak - Gukasyan 1989, Loma Prieta - Corralitos 1994, Northridge - LA Century City 1979, Imperial Valley - Array 7 Envelope

3.5

120

3

100

2.5

80

2

60

1.5

acceleration (g)

40

1

displacement (cm)

20

0.5

0

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)

(b)

(a)

Figure 3. FEMA307 (1999) spectra: short duration. Spectral accelerations (a); Spectral displacements (b). The second category, the long duration motions, consists of records from 1940 El Centro, 1978 Tabas, 1985 Chile and 1992 Landers earthquakes. The envelopes of the acceleration and displacement response spectra corresponds to the Tabas spectra, with a maximum spectral acceleration equal to 3.7g at 0.2s, an amplification range until the period of 0.9s and values of 0.5g at longer periods (Figure 4a) and a maximum spectral displacement of 64.30cm at 3s (Figure 4b).

4

140

1985, Central Chile - Lllolleo 1985, Central Chile - Valparaiso 1940, Imperial Valley - El Centro 1978, Tabas - Tabas 1992, Landers - Joshua Tree Envelope

1985, Central Chile - Lllolleo 1985, Central Chile - Valparaiso 1940, Imperial Valley - El Centro 1978, Tabas - Tabas 1992, Landers - Joshua Tree Envelope

3.5

120

3

100

2.5

80

2

60

1.5

acceleration (g)

40

1

displacement (cm)

20

0.5

0

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)

(b)

(a)

Figure 4. FEMA307 (1999) spectra: long duration. Spectral accelerations (a); Spectral displacements (b). The forward directivity category consists of motions from 1979 Imperial Valley, 1989 Loma Prieta, 1992 Landers, 1994 Northridge and 1995 Kobe events. The acceleration response spectra in Figure 5a are characterized by larger amplification zones, up to 1.8s with a maximum value of 2.15g at 0.65s (1994 Northridge Earthquake, Newhall LA County Fire Station) and up to 2.4s with a maximum value of 2.09g at 1.2s (1995 Kobe Earthquake, Takatori Station). The envelope of the displacement response spectra in Figure 5b corresponds to the Takatori spectrum, with a maximum spectral value equal to 115.07cm at 2.0s. The form of this displacement spectrum is different from the others because of its decreasing trend for periods longer than 2s.

1992, Landers - Lucerne 1979, Imperial Valley - Brawley Airport 1989, Loma Prieta - Saratoga Aloha Avenue 1994, Northridge - Newhall LA County Fire 1994, Northridge - Sylmar County Hospital 1995, Kobe - Takatori Envelope

4

140

1992, Landers - Lucerne 1979, Imperial Valley - Brawley Airport 1989, Loma Prieta - Saratoga Aloha Avenue 1994, Northridge - Newhall LA County Fire 1994, Northridge - Sylmar County Hospital 1995, Kobe - Takatori Envelope

3.5

120

3

100

2.5

80

2

60

1.5

acceleration (g)

40

1

displacement (cm)

20

0.5

0

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)

(b)

(a)

Figure 5. FEMA307 (1999) spectra: forward directivity. Spectral accelerations (a); Spectral displacements (b).