PSI - Issue 84

Diego Esposito et al. / Procedia Structural Integrity 84 (2026) 1198–1205

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Figure 6. Comparative analysis of theoretical deflections versus measured values obtained from the three load tests on the various tested spans.

Analysis of the time history from the crack monitoring system, installed during the load test on selected cracks in the deck girders, indicates that the greatest increase in recorded displacement (opening of the displacement transducer) coincides with the entry of the second row of trucks (from 2B to 3A) (Figure 7). This evidence confirms that this step load represents the most influential contribution to the variation in structural stiffness.

-0.25 -0.20 -0.15 -0.10 -0.05 0.00 0.05

0

0

1A 1B

2A

2B

3A

3B

Δ (mm)

4A

4A

4B

0

2000

4000

6000

8000

10000

Tempo (sec)

12000

Figure 7. Monitoring of the crack in span C1 during the load test.

Finally, Figure 8 shows the evolution of the rotation angle of the midspan section of the deck (torsion), calculated from the deflections at the two outermost points (M1 and M3) as the load configurations vary, along with a comparison to experimental values.

Figure 8. Comparison of the Rotation of the Midspan Section of the Deck.

Comparison of experimental and theoretical results highlights that the calculation model based on the full stiffness of the structure never accurately represents the real behavior, especially under higher load conditions where significantly greater deflections were recorded. In the initial loading phases, however, a numerical simulation with stiffness equal to 70% of the original (E70%) appears more consistent with experimental data. From load configuration 3A onward, a clear change in stiffness is observed in the load–deflection response. Nevertheless, further reduction of