Matthew Murphy
Andrew Goulding
Jennifer Young
Rosanna Kleemann
Background
 241m (60 storey) Skyscraper in Boston
 Constructed for John Hancock Insurance
 Tallest building in New England
 Designed by I.M Pei and Cobb
 Constructed 1968-1976 for $175M
 Plagued by Design and Engineering Flaws
Design
 Changed Skyscraper Design
 Concrete columns to concrete cores
 Rectangular to parallelogram floor plan
 Glass Facade
 Blue tinted reflective glass
 Blends into Boston skyline
The Beginning of Failures
 Excavation and foundation collapse
 Swaying of the tower
 Facade Failure – Falling glass
Facade Failure
 One acre of glass panes failed
 Falling to the streets below
 Plywood panals used as temporary replacement
 “Plywood Palace”
Myths about Failure
 Increased stesses due to swaying tower
 “Hot Spots” due to rhombus shape
 Increased Pressure due to Foundation Settlement
Actual Cause of Failure
 New Window Design – insufficient testing
 Bond between reflective coating and lead spacer too
strong!
 Bond too stiff to allow any movement
 Increase stress on glass due to thermal movement and
wind vibrations
 Cracks formed and falling glass!
Consequences of Failure
 Replacement of 10,344 panes of glass by tempered
safety glass
 Cost of over $8.5 Million
 Delay in opening date by 4 years
Conclusion
 Major Financial Implications
 Delays in completion date
 New Regulations on high rise building design
 Improved wind tunnel testing