PSI - Issue 84

Ana Avramova et al. / Procedia Structural Integrity 84 (2026) 560–568

564

(a)

(b)

Fig. 5 Time evolution of the identified natural frequencies of (a) VI03 and (b) VI04 viaducts (from 05/06/2024 to 01/10/2025). Table 1 VI03 viaduct: statistics of the identified modal parameters (from 05/06/2024 to 01/10/2025). Mode f avg (Hz)  f (Hz) f min (Hz) f max (Hz) f 2 −T MAC avg  MAC B 1 1.541 0.011 1.515 1.581 0.878 0.9996 0.0005 T 1 1.825 0.022 1.786 1.909 0.921 0.9907 0.0126 B 2 1.945 0.014 1.918 1.996 0.905 0.9991 0.0008 T 2 2.193 0.025 2.145 2.283 0.918 0.9944 0.0085 B 3 2.481 0.016 2.448 2.539 0.891 0.9993 0.0018 T 3 2.684 0.026 2.636 2.780 0.901 0.9913 0.0117 B 4 2.869 0.016 2.833 2.937 0.870 0.9984 0.0022 T 4 3.029 0.025 2.984 3.121 0.887 0.9896 0.0140 B 5 5.299 0.029 5.235 5.434 0.907 0.9980 0.0024 T 5 5.578 0.047 5.479 5.743 0.910 0.9727 0.0192 B 6 5.963 0.036 5.875 6.109 0.861 0.9943 0.0046 T 6 6.185 0.057 6.051 6.378 0.755 0.9618 0.0203

f max (Hz) f 2 −T MAC avg  MAC 1.451 0.663 0.9999 0.0002 0.9912 0.0123

Table 2 VI04 viaduct: statistics of the identified modal parameters (from 05/06/2024 to 01/10/2025). Mode f avg (Hz)  f (Hz) f min (Hz)

B 1 T 1 B 2 T 2 B 3 T 3 B 4 T 4 B 5 T 5 B 6 T 6 B 7 T 7

1.410 1.678 1.860 2.112 2.405 2.636 2.734 2.946 4.820 5.159 5.520 5.805 6.343 6.770

0.010 0.018 0.012 0.023 0.016 0.025 0.015 0.024 0.024 0.040 0.031 0.047 0.056 0.039

1.390 1.642 1.837 2.072 2.376 2.593 2.700 2.896 4.766 5.079 5.441 5.701 6.217 6.685

1.759 1.916 2.204 2.473 2.740 2.801 3.040 4.948 5.325 5.671 5.999 6.604 6.941

0.906 0.772 0.903 0.878 0.893 0.812 0.888 0.874 0.873 0.862 0.860 0.850 0.849

0.9996 0.0004 0.9937 0.0083 0.9996 0.0005 0.9823 0.0177 0.9979 0.0032 0.9955 0.0076 0.9992 0.0008 0.9828 0.0150 0.9961 0.0031 0.9760 0.0180 0.9929 0.0062 0.9549 0.0245

The inspection of Errore. L'autoriferimento non è valido per un segnalibro. (VI03 viaduct) and Table 2 (VI04 bridge) confirms that the natural frequencies exhibit relatively low variations, with standard deviations