Dynamic Racking Crescendo Tests on Architectural Glass Fitted with Anchored Pet Film

Results are presented of a pilot study conducted recently at the Pennsylvania State University Building Envelope Research Laboratory (BERL) to investigate the response of curtain wall mock-ups glazed with 6 mm $(\frac{1}{4}$ in.) annealed monolithic architectural glass panels fitted with anchored applied film under simulated earthquake conditions. Three common film-to-frame anchoring methods were evaluated: (1) structural silicone adhesive [13 mm $(\frac{1}{2}$ in.) triangular cross section] application along the entire glass panel perimeter; (2) an aluminum bar extrusion to anchor the film to the frame horizontal along only the top of the glass panel; and (3) two aluminum bar extrusions to anchor the film to the frame verticals along the two vertical edges of the glass panel. Serviceability (glass cracking) and ultimate (glass fallout) limit-state data were collected during in-plane dynamic racking tests. Other performance characteristics, such as cohesive failure of the structural silicone adhesive, loss of film-to-glass adhesion, film tearing, damage to aluminum anchor bars, pullout of the filmed glass unit from the frame glazing pockets, and eventual entire unit fallout, were also recorded. These preliminary tests indicated that anchorage type can demonstrably influence both the serviceability (initial glass cracking) and ultimate (glass fragment fallout and entire unit fallout) limit states of “unweathered” filmed glass panels. In this study, the structural silicone anchor provided the best serviceability limit-state performance of the three anchor methods tested, and the top anchor provided the best entire-unit glass fallout resistance.