## 5 Test Results and Interpretation
### Horizontal Displacements of Supports  
The horizontal transverse (X) and longitudinal (Y) displacements of the north abutment bearings (Au and Ad) and of the isolator (I) that was placed in correspondence of the north pylons are measured during the whole phases of the proof load test. The recorded displacements of each transducer (positioned as reported in Figure 4) are plotted in Figure 13, obtaining displacement profiles that describe the evolution of the support movements (and hence of the bridge deck) during tests.  
The values of the longitudinal displacements (Au-Y, Ad-Y, and I-Y) are fully consistent with the expected rotations in the measured cross-sections of the deck because of the applied loads. Actually, in phase L5 the applied loads determine the downward deflection of the loaded central span and the uplift of the lateral spans with consistent rotations of the deck cross-sections at the supports, which are opposite in sign for the north pylon and the north abutment. Rotations of the cross-sections at the supports determine displacements at transducers that are directed towards the center of the lateral span (positive displacements). On the other hand, in phase L10 the applied load causes the downward deflection of the lateral span with consequent rotations of the deck cross-sections at the north abutment and north pylons, which determine displacements that are directed in the opposite direction with respect to the previous one (negative displacements).  
The values of the transverse displacements (Au-X, Ad-X, and I-X) are almost zero for C1, while they have positive values for the load in the lateral span (C2), due to the tendency of the deck to translate downstream for the applied loads.  
Figure 13: Horizontal longitudinal and transverse displacements of monitored supports.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Point**} & \multicolumn{2}{c}{**Longitudinal Displ. (Y) [mm]**} & \multicolumn{2}{c}{**Transverse Displ. (O) [mm]**} \\ \cline{2-5}  & **EXP** & **NUM** & **EXP** & **NUM** \\ \hline NP1 & 63.5 & 106.5 & \(-31.5\) & \(-26.4\) \\ NP2 & 48.3 & 77.3 & 23.9 & 19.8 \\ SP1 & \(-67.4\) & \(-107.3\) & \(-30.4\) & \(-26.3\) \\ SP2 & \(-46.3\) & \(-76.0\) & 27.2 & 22.0 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison between the experimental and numerical displacements of the investigated pylon points in C1 load configuration.  
The higher displacements that were experienced during C2 (especially the transverse ones) are due to the position of trucks in the same lateral span where the displacements are measured. The residual displacements are almost negligible after the C1 load configuration (phase L6, with a maximum residual value around 2.5 mm) and very small after C2 (phase L11, with a maximum residual value around 5 mm). It is worth remarking that small residual displacements are physiological during tests and can be also attributable to thermal effects, which are not numerically investigated in view of the uncertainties relevant to the temperature gradient within the deck cross-section and the thermal effects on stays. Indeed, as shown in the sequel, the temperature significantly increased during the period in which the load tests were executed; consequently, a possible contribution of the thermal effects on the measured displacements, producing a deck elongation, cannot be excluded.  
The developed numerical model was used to interpret the data of transducers at the supports. As an example, Table 4 compares the measured displacements at the isolators with the corresponding numerical values; the experimental data are reproduced quite closely by the numerical model.