Volume 1, Issue 1
Seismic Performance of Stick-Built Four-Side Structural Sealant Glazing Systems and Comparison With Two-Side Structural Sealant Glazing and Dry-Glazed Systems
A research project was undertaken to study the simulated seismic performance of mock-ups of a full-scale, four-side structural sealant glazing (SSG) system. “Stick-built” mock-ups were subjected to cyclic racking displacements in accordance with the American Architectural Manufacturers Association (AAMA) 501.6 test method. Although the test method focuses on glass fallout, drifts associated with serviceability damage states, such as sealant adhesive or cohesive failure, and glass cracking were also identified during the conduct of the tests. Damage to sealant joints was tracked as a function of drift level using visual and video inspections of weather-seals and structural-seals and air-leakage tests. Data from this study are compared with data collected from similar studies on comparable two-side SSG and dry-glazed mock-ups. Contact with panels diagonally above and below a given glass panel at panel corners was found to be the likely cause of initial sealant damage, glass cracking, and glass fallout as opposed to glass-to-frame interactions for two-side SSG and dry-glazed curtain-wall constructions. Thus, modified corner geometries and/or joint dimensions can be used to delay (i.e., shift limit states to higher drift levels) or avoid these damaging panel interactions. Mock-up specimens were also instrumented extensively so that real-time glass-panel translation and rotation, and weather-seal deformation measurements could be recorded. A summary of these measurements is presented and discussed in the context of their follow-up use for informing the development of damage prediction models for SSG curtain walls during seismic loadings. The study shows that stick-built curtain walls with four-side SSG configuration are expected to have higher drift capacity compared to two-side SSG and both are expected to have higher drift capacity compared to dry-glazed configurations.