Group 8 John Hancock TowerFacade Failure

Matthew MurphyAndrew Goulding

Jennifer YoungRosanna Kleemann

Background241m (60 storey) Skyscraper in BostonConstructed for John Hancock InsuranceTallest building in New EnglandDesigned by I.M Pei and Cobb Constructed 1968-1976 for $175MPlagued by Design and Engineering Flaws

DesignChanged Skyscraper Design

Concrete columns to concrete coresRectangular to parallelogram floor plan

Glass FacadeBlue tinted reflective glassBlends into Boston skyline

The Beginning of FailuresExcavation and foundation collapse

Swaying of the tower

Facade Failure – Falling glass

Facade FailureOne acre of glass panes failed

Falling to the streets below

Plywood panals used as temporary replacement“Plywood Palace”

Myths about FailureIncreased stesses due to swaying tower

“Hot Spots” due to rhombus shape

Increased Pressure due to Foundation Settlement

Actual Cause of FailureNew Window Design – insufficient testingBond between reflective coating and lead

spacer too strong!Bond too stiff to allow any movementIncrease stress on glass due to thermal

movement and wind vibrationsCracks formed and falling glass!

Consequences of FailureReplacement of 10,344 panes of glass by

tempered safety glass

Cost of over $8.5 Million

Delay in opening date by 4 years

ConclusionMajor Financial Implications

Delays in completion date

New Regulations on high rise building design

Improved wind tunnel testing

Thank you!