PSI - Issue 78

Elisa Tomassini et al. / Procedia Structural Integrity 78 (2026) 1831–1838

1834

4

Author name / Structural Integrity Procedia 00 (2025) 000–000

+4.41

0.00

-32.2

47.77

y

x

z

Temperature sensor

SHM triaxial accelerometer

SHM uniaxial accelerometer

Seismic triaxial accelerometer

(a)

(b)

Fig. 1: (a) Permanent SHM sensor network layout installed in the Marmore Bridge and (b) picture of the Marmore bridge.

AutoMAC matrix

Mode

Mode

Mode 1 Mode 9 Mode 17

Mode 2 Mode 10 Mode 18

Mode 3 Mode 11 Mode 19

Mode 4 Mode 12 Mode 20

Mode 5 Mode 13 Mode 21

Mode 6 Mode 14 Mode 22

Mode 7 Mode 15 Mode 23

Mode 8 Mode 16

(a)

Mode 7

Mode 1

Mode 2

Mode 3

Mode 4

Mode 5

Mode 17

Mode 8

Mode 13

Mode 18

Mode 22

Mode 12

(b)

Fig. 2: (a) Stabilization diagram (December 12, 2024, 3:00 a.m) and MAC matrix of the identified modes of the Marmore bridge. (b) Some of identified mode shapes.

The reference dynamic properties of the Marmore Bridge were established using the Cov-SSI method, as imple mented in the P3P platform (see Garc´ıa-Mac´ıas et al. [2022]). The analysis was performed on the set of ambient vibration time histories acquired on December 12 th , 2024, at 3:00 a.m. A stabilization diagram was constructed by evaluating system model orders ranging from 100 to 200, with an increment of 2. The Toeplitz covariance matrices were computed using a time lag τ of 2.2 s. Stable pole selection was conducted in accordance with the automated methodology proposed by Reynders et al. [2011], applying both modal stability and quality criteria. Specifically, poles associated with damping ratios greater than 10% or MPC values below 60% were excluded. To assess the