Development of kinematic equations for racking performance evaluation of four-sided structural sealant glazing curtain wall systems

Full-scale, unitized, four-sided structural sealant glazing (4SSG) curtain wall system mock-ups featuring a re-entrant corner were subjected to cyclic racking displacements in accordance with the American Architectural Manufacturers Association AAMA 501.6 protocol to determine serviceability and ultimate behavior responses. Sealant cohesive failure and glass cracking were identified as limit states and corresponding drift levels were determined. The geometry of the mock-up was used to develop equations that predicted the displacements of the glass, relative to the frame, based on the independent variable of inter-story drift. The displacements from those equations were then related to the effective shear strain of the structural silicone and the drift capacity of the system. This paper describes the concepts and results of the kinematic equations developed.