PSI - Issue 78

Abed Soleymani et al. / Procedia Structural Integrity 78 (2026) 815–822

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software allows the user to select sets of accelerograms that are compatible with 5%-damped elastic design spectrum of technical codes, such as the Italian technical code (herein abbreviated as NTC 2018) and Eurocode 8 – Part 1 (herein abbreviated as EC8-1; see EN1998-1, 2004). Firstly, it is necessary to define key parameters, including design earthquake (source) parameters, spectrum matching parameters, and analysis options. In this study, according to EC8 – 1 (EN1998-1, 2004), a higher level of seismic action was considered for the spectrum type corresponding to surface-wave magnitude greater than 5.5. The interval of the moment magnitude ( ) and epicentral distance ( ) was respectively equal to [5.5, 8] and [0 km, 30 km] to properly reflect the characteristics of seismic sources, considering the effects of near-field strong motion records (Smerzini et al., 2012). Then, the design ground acceleration parameter ( ) on soil class of type A was considered based on the geographical coordinates of the structure (latitude and longitude parameters). To select spectrum-compatible records, a nominal lifetime equal to 50 years was considered for life safety limit state. In spectrum matching criteria, the range of period between 1 =0.2 2 and 2 =2 1 , where 1 is the fundamental period of the structure in the X-direction and 2 is the fundamental period of the structure in the Y-direction, was applied to match accelerograms with the target (design) spectrum. Moreover, parameters of tolerance below average and tolerance above average were respectively assumed to be 10% and 30% in order to define the compatibility tolerance with respect to the average spectrum. Finally, a set of seven groups of accelerograms (A1, A2, A3, A4, A5, A6, and A7), each consisting of two horizontal orthogonal components of the record, was specified in the software. Spectra including design target spectrum, lower and upper tolerance of target spectrum, spectra related to seven two-component natural accelerograms found for the assigned location coordinates through REXELweb and the corresponding average spectrum are shown in Fig. 3, where vertical and horizontal axis represent Peak Spectral Acceleration (PSA) and vibration period, respectively. Besides, essential record data and some key ground motion parameters are presented in Table 2.

Fig. 3. Target spectrum and spectra related to the seven two-component natural accelerograms selected at the site through REXELweb.

Table 2. Essential record data proposed by REXELweb for the set of combination records Accelerogram ID A1 A2 A3 A4 A5 A6

A7

EMSC 20161026_00 00095

EMSC 20160824_ 0000006

EMSC 20161026_0 000095

EMSC 20161026_0 000095

EMSC 20161030_ 0000029

EMSC 20161030 _0000029

IT-1978 0004

Event ID 1

Station code

MZ04

CSC

T1244 Normal

PTT1

T1201 Normal

T1241 Normal

T1256 Normal

Fault mechanism Normal

Normal

Strike-slip

M

5.9

6.0

5.9

6.0

5.9

6.6

6.6

R [km]

29.1

18.3

21.3

18.3

29.5

25.3

20.5

E: 1.000 N: 1.000

E: 1.000 N: 1.000

E: 1.000 N: 1.000

E: 1.000 N: 1.000

E: 1.000 N: 1.000

E: 1.000

E: 1.000

Scale factor

N: 1.000 N: 1.000

1 Event ID in the Engineering Strong Motion (ESM) database according to REXELweb According to seismic analysis results, failure mechanisms of structural elements were restricted to shear failure of deck beams and arch elements for the examined bridge. In all cases, shear failures mostly occurred at the ends of the