Pre- and Post-fracture Experimental Vibration Analysis for In-Field Damage and Vulnerability Measure in Existing Glass Slabs

The vibration performance of pedestrian structures attracts the attention of several studies, especially with respect to unfavorable operational conditions or possible damage scenarios. Specific vibration comfort levels must be satisfied in addition to basic safety requirements, depending on the class of use, the structural typology and the materials. Careful consideration could be then needed not only at the design stage, but also during the service life of a given glass walkway or pedestrian system. Moreover, accidental events may require rapid diagnostic analyses with minimized efforts. In this paper, the attention is focused on the vibration analysis of in-service laminated glass slabs that are part of an indoor, case-study walkway. The attention is focused on modular units with identical geometry and restraints, but intact (LGU) or partially fractured (LGF) glass layers (as it was in August 2021). The in-field rapid analysis of classical performance indicators is thus addressed. Among others, dynamic identification techniques are applied for the analysis of the pre- and post-fracture vibration performances in order to quantify the effect of damage in glass. Parametric experimental outcomes are thus discussed in the paper, as obtained from Operational Modal Analysis under emergency experimental setup