Dynamic Identification Techniques for the Vulnerability Analysis of Glass Soft Targets: On-site Vibration Experiments and Numerical Simulations on a Glazed Footbridge

The use of glass in buildings as load-bearing material showed an exponential increase. Although it represents a relatively new solution for constructions, requiring appropriate design knowledge, glass is frequently used for facades, roofs, footbridges, etc. Deep care should be certainly spent at the design stage – to ensure reliable fail-safe requirements – but also during the life-time of glass structures. The brittle behaviour and limited tensile resistance of material, in addition to the high flexibility of glass assemblies, are responsible of major issues for structural engineers. Further criticalities are represented by time and ambient effects, or extreme loads. The vulnerability assessment of glass structures is hence an open topic, still requiring huge efforts. A combination of multiple aspects should be properly assessed to ensure appropriate protection and mitigation, especially for glazed soft targets. In this paper, dynamic identification methods are used for an in-service glass footbridge. On-site vibration experiments are discussed, including Finite Element numerical analyses, so as to explore the footbridge dynamic performance and assess its vulnerability.