Employing glass panels with rounded corners to mitigate seismic damage in architectural glass wall systems

Racking motions during an earthquake can lead to serviceability failure (e.g., glazing gasket pullout, sealant damage, glass edge damage and glass cracking) or even ultimate failure (in the form of glass fallout that presents a threat to life safety) in conventionally glazed wall systems - even those that meet current building code provisions for nonstructural elements. A new approach to mitigation of seismic risk in conventionally glazed wall systems with architectural glass panels has been developed at the Building Envelope Research Laboratory (BERL) at The Pennsylvania State University. The essence of the approach is to modify the rectangular geometry of architectural glass panels at the corners through rounding. A pilot study at BERL has shown that rounding the corners of architectural glass panels can increase the drift capacity of the panels significantly and that maximum effectiveness is achieved by employing rounded corners with a 1 in. radius of curvature along with beveled and polished glass edges. Results of these in-plane dynamic racking tests performed on full-scale mock-ups of curtain wall sections glazed with architectural glass panels of different glass types, employing various radii of curvature at the corners, various glass edge conditions, and varying glass-to-frame clearances are presented.