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Abstract. The work reported herein summarizes the results of a series of nonlinear dynamic FE analyses devoted to assess the main criticalities in the seismic

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The construction sector is experiencing significant technological innovations with digitalisation tools and automated construction techniques, such as additive manufacturing. Additive manufacturing utilising cement-based materials can potentially remove the technological/economic barriers associated with innovative architectural/structural shapes which are not suitable for conventional formworks adopted for concrete material. However, in the “free-form” digital fabrication with concrete, the mechanical properties prediction of the material in the fresh state is essential for controlling both the element deformations and overall stability during printing. In this paper, the authors explore the critical aspects related to the determination of the early-age creep properties of a 3D printable cement-based material, particularly investigating such a behaviour at different resting times. The experimental results are used to calibrate the Burgers’ analytical model to consider both the elastic and the viscous response of the 3D printable mortar investigated in the fresh state. The visco-elastic model is validated by comparing the analytical total strain vs time curve with the corresponding experimental counterpart replicating the layer-by-layer stacking process in the 3D concrete printing process. It was found that the Burgers’ model represents a valuable numerical approach to evaluate the overall accumulation of layer deformation of a 3D printed element, since it is capable of taking into account the time dependency due to the time gap and the variable material stiffness over the process time.

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Abstract. The results derived from the investigation on the dynamic behavior of glazed curtain wall non-structural stick systems installed in modern high-rise mega-frame prototypes is herein summarized. The supporting steel structures, designed in accordance with European rules, consisted of planar frames extracted from reference three-dimensional steel Moment Resisting Frame (MRF), respectively having thirty-and sixty-storey height. To limit interstorey drift and second order effects, outriggers trusses were placed every fifteen stories, whilst a CBF system was chosen as internal core. The characterization of non-structural façade elements was performed through experimental full-scale crescendo-tests on aluminium/glass curtain wall units. Deriving experimental force-displacement curves, it was possible to calibrate threedimensional inelastic FE models, capable to simulate the interaction between glass panels and aluminium frame. Subsequently, equivalent nonlinear links were calibrated to reproduce the dynamic behaviour of tested glazed unit, and implemented in the thirty-and sixty-storey structural planar frames FE models. Nonlinear time history analyses (NLTHAs) were performed to quantify local and global performance, investigating the enhanced combination of stiffness and strength generated through the implementation of glazed curtain wall on the numerical FE models. Results will be shown in terms of inter-storey drift profiles and displacement peaks, axial force curves and percentage peak variation, showing the sensitivity to the structure height. Trends were discussed to show that, if accurately designed, omitting non-structural elements from the seismic assessment of high-rise prototypes conduct to a sensible underestimation of dynamic dissipation capacity of the building.