John Hancock
Building
Façade failures.
Group 8
Introduction
Boston
60 Storie steel frame structure
One of the World’s largest
buildings
Fully Glazed façade
What Happened?
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In 1972/73 a windstorm hit Boston
Cracking of exterior panes
Panes broke away from building
Broke other panes on its way down
“Gag order” imposed for 17 years
Why?
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Stress caused by settlement
No!
Sway of tower (0.9m sway)
Not exactly!
Why?
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Copper on glass with Lead spacer
Bond was too strong between panes
Outer pane could not flex with
structure
Bond ripped glass from broken
pane!
Managerial mistakes
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Not enough research on façade
No specification for sway
Lessons Learned
• Sparked research into structural behavior
• The problem with the glass was identified
• Facades are now better designed