Seismic behavior of a fully tempered insulating glass curtain wall system under various loading protocols

This paper investigates the seismic behavior of a glass curtain wall system under various loading scenarios. Experimental set-ups and approaches were developed to test full-scale fully tempered (FT) insulating glass curtain wall systems subjected to three loading protocols: quasi-static in-plane loading, dynamic in-plane loading, and dynamic coupled in-plane and out-of-plane loading. A refined finite element (FE) model was developed to understand the behavior of the system. The average drift associated with glass cracking and fallout was found to be nearly identical for quasi-static and dynamic in-plane loading, indicating that in-plane floor accelerations exerted marginal influence on the failure of the glass curtain walls. Bi-directional loading led to an approximately 30% decrease in the glass fallout drift compared with in-plane loading. This is because the out-of-plane drift placed an increased stress demand on the glass panel, as indicated by the FE analysis. Both the experimental tests and FE analysis revealed that the ASCE 7-16 formula, which is used to calculate the drift of contact between the glass and frame, is nonconservative as it does not consider the deformation of the surrounding frame and the friction between the gasket and the glass. The failure mechanism of the glass panel was caused by the stress concentrations at the diagonal corners due to glass-to-frame contact. The FE analysis indicated that the interactional effect among different glass units was negligible, and the glass panels exhibited a similar stress state regardless of their positions.