Historical Failures, Lessons Learned and Design Improvements

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Historical Failures, Lessons Learned and Design
Improvements

• H. N. Hashemi
• MIME Dept.

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Turbo-Generator Shafts Failure
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Shaft is subjected to transient Torques
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Mode of Failure
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Life Estimation
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Failure Modes
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ISUZU Failure of the Break
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Inspection of the System
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Mechanism of Failure
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Metallography Study
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Merrimack River Dam Failure

• Mechanism of Failure, Strain Hardening of Rods

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Hyatt Hotel Failure in Kansas City
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Design and Factual Information

• Hyatt Walkway Collapse
• Kansas City Hyatt Regency hotel opened in 1980
• 40-story tower
• Function block
• Connecting atrium with three elevated walkways
  117 ft (36 m) long

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Initial Design

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Designed was changed to this
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The Change in Design Doubled the stress in the
joint
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Since both the 4th and 2nd floor walkways fell,
which parts of the walkways could have failed?
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1940 suspension bridge in Washington state
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Third-longest in the world in 1940 (5000 ft
2800 ft center span) Quite narrow (39 feet two
lanes) Bridge deck supported by vertical cables
hung from two long cables strung from one shore,
over two towers, to other shore
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• To reduce costs, sides constructed of solid
  8-foot tall I-beams rather than typical open
  trusses

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November 7, 1940 (four months after opening)

• Midnight storm weakens bridge deck and cable
  stays
• Mid-morning wind reaches 40-45 mph
• Bridge closed at 10 am and bridge begins
  torsional wave motion

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Why did this bridge oscillate so much? Why did
this bridge fail when other, longer bridges
didnt? What design changes might have prevented
this failure?
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• Solid I-beam girders, unlike trusses, did not
  allow wind to flow through Flexible bridge
  oscillated vertically (transverse waves) due
  to vertical forces from vortex shedding as wind
  flowed around side girders

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Why did this bridge fail when other, longer
bridges didnt?

• More Vertical Deflection
• More Torsional Deflection

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Failure Due to Inspections

• Nondestructive Evaluation such as
• Ultrasonic
• Eddy Current
• Thermography
• Radiography
• Vibrations
• Etc.

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I 95 Bridge section failure due to missing a
large crack during inspections of the bridge
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Poor inspections, missing cracks, resulted in a
disaster
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• Thank you