Mianus River Bridge Collapse.ppt
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Transcript Mianus River Bridge Collapse.ppt
Mianus river bridge collapse
Contents
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Introduction
Structural Design
How the bridge collapsed
Maintenance issues
The aftermath
Questions
Introduction
• Constructed in 1957
• Effectively two
bridges
• It carrys over one
hundred thousand
cars daily
• Multiple-span
structure
Structural Design Flaws
• Cantilevered bridge with two suspended spans
• Pin and hanger assembly used to hang
suspended spans
• This assembly was recognised as being unsafe
since 1968
How the bridge collapsed
• Pin and hanger
assembly failed
• No redundancy
• Weakened by rust
• Exposed to lateral
loads
Maintenance issues
• Bridge inspected (poorly) once every two
years
• Drains were paved over
• Corrosion accumulated
• Corrosion in vital areas went undetected
The aftermath
• Three people killed
• 10-year $5.5 billion
bridge maintenance and
inspection program
• Paved-over drains
reopened
• Bridge made more
“inspectable”
• Pin and hanger assembly
bridges designated for
more frequent inspection
Questions?
• Thank You