PSI - Issue 62

Andrea Meoni et al. / Procedia Structural Integrity 62 (2024) 73–80 Meoni et al/ Structural Integrity Procedia 00 (2019) 000 – 000

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4.2. Module for structural performance evaluation Visual inspections of the case study bridge pointed out marked downward deflection of the box girder at the vertically prestressed structural joints, while the remaining spans were found to be deflected upward, with the maximum deflection detected at the middle section of every span. Detachments between the upper and lower sliders of the sliding supports positioned at the structural joints were also noted. Some of the bearing supports of the structural joints were characterized by longitudinal sliding exceeding the maximum admissible displacement. The latter defect also affects the sliding supports positioned at the top of the piers. Diagonal cracks of small opening were detected on the concrete box girder near the structural joints and piers. The extent of the detected structural defects was evaluated by considering the five defect levels defined by the Italian Guidelines (high, medium-high, medium, medium-low, and low defect level) via the Structural Defect Monitoring module. Figure 6 shows the defect level determined for each superstructure/substructure composing the case study bridge. In particular, the high defect level was attributed due to detachments and excessive longitudinal sliding at the sliding supports of the bridge, as well as in the presence of diagonal cracks. Figure 7 points out the results of the superimposition of the point cloud on the 3D digital model of the bridge; an enlarged view showing the excessive longitudinal sliding detected on a sliding support of the structural joint of span no. 7 is also reported. Acceleration signals acquired by performing AVTs on the case study bridge were processed through the Acceleration Processing and Operational Modal Analysis modules. Figure 8 shows the main panel of the Acceleration Processing module, where the pre-processing operations can be set, hence the plot of the acceleration signals after pre-processing. Figure 9 illustrates the results obtained from the Operational Modal Analysis module. Specifically, Fig. 9(a) shows the plot of the singular values of the spectral matrix of recorded accelerations with the first three resonant peaks selected, while Fig. 9(b) represents the modal features of every identified mode of vibration, i.e., its natural frequency (mode no. 1 at 1.19 Hz, mode no. 2 at 1.36 Hz, and mode no. 3 at 1.51 Hz) and mode shape (the latter through its animation).

Fig. 6. Module for structural performance evaluation: (a) defect level estimated for the Structural-Foundational Class of Attention; (b) defect level estimated for the Seismic Class of Attention. 5. Conclusion The paper has proposed a new framework for informed management of bridges in BIM environments, based on their risk conditions and structural performance assessment. A new Revit add-in was also introduced to exemplify