Numerical assessment of vibration control systems for multi-hazard design and mitigation of glass curtain walls

Glass systems and facades are widely used in building structures, due to a multitude of aspects. Beside these motivations, from a pure structural point of view, glazing envelopes represent one of the most critical components for multi-storey buildings under the action of exceptional loads as impacts, explosions, seismic events or hazards in general. Such systems represent in fact the first line of defense from outside. Given the current lack of specific design regulations for the mitigation and enhancement of glass curtains under extreme loads, as well as the typically brittle behaviour and limited tensile resistance of glass as material for constructions, the same facades require specific, fail-safe design concepts. In this paper, the feasibility and potential of special mechanical connectors interposed at the interface between a multi-storey primary building structure and the enclosing glazing facade are investigated via accurate Finite-Element (FE) numerical models, under various impact scenarios. At the current stage of research, careful consideration is given both to the observed global performances as well as to local mechanisms, based on computationally efficient FE models inclusive of damage models to account for failure mechanisms in each system component. Compared to earlier research efforts, the attention is focused on the multi-hazard performance of a given case study building, subjected to extreme loadings such as seismic loads or blast events. As shown, even the typically different features of the examined loading conditions, when the proposed vibration control devices are properly designed and the curtain wall is considered as part of a full 3D building, the final result is an overall assembled structural system in which the glazing facade can work as a passive control system for the building system, in the form of a distributed Tuned-Mass Damper (TMD), with marked benefits in terms of protection level as well as design optimization.