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Transcript of Failure By Design Inquiry Physics .
Failure By Design
www.failurebydesign.infoInquiry Physics
www.inquiryphysics.org
Purpose
Tacoma Narrows Bridge CollapseExamine different types of wave
motion and how aerodynamic effects destroyed a structure
Hyatt Hotel Walkway CollapseUse your analytical and deductive
skills to speculate about what caused a structural disaster
Hyatt Walkway CollapseKansas City
Hyatt Regency hotel opened in 198040-story towerFunction blockConnecting atrium with three elevated walkways 117 ft (36 m) long
The Disaster
Atrium crowded with 1500-2000 people for a dance competitionSecond and fourth-floor walkways collapsed114 people killed, over 200 injured
July 17, 1981(one year after opening)
Hyatt Walkway CollapseThe Disaster
The Disaster
2nd-floor walkway designed to hang from 4th-floor walkway, which was hung from roof by three rods along each side of its 117 ft (36 m) length
3rd floor walkway was separate and survived
Hyatt Walkway CollapseThe Disaster
The Puzzle
Since both the 4th and 2nd floor walkways fell, which parts of the walkways could have failed?
Hyatt Walkway CollapseThe Puzzle
The Puzzle
What evidence would you look for to decide which part did fail?
Hyatt Walkway CollapseThe Puzzle
Hyatt Walkway Collapse – The Puzzle
Hyatt Design Animation
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file takes awhile
to load…
The Puzzle
Have you decided which part most likely failed?
Next is an important clue.
Hyatt Walkway CollapseThe Puzzle
The Puzzle: A Clue
Design ChangeOriginal design used single rods to support both walkways, but they would have been awkward to install and thread.
Each rod would have connected to 4th-floor walkway as shown.
Hyatt Walkway CollapseThe Puzzle: A Clue
The Puzzle: A Clue
Design ChangeAs-built, the single long rods were replaced by a pair of shorter rods connecting to the 4th-floor walkway as shown.
Hyatt Walkway CollapseThe Puzzle: A Clue
Hyatt Walkway Collapse – The Puzzle: A Clue
Hyatt Design Change
The Puzzle: A Clue
How did the design change affect the physics of the walkway connection?
Now which part do you think failed?
It is time to view the evidence…
Hyatt Walkway CollapseThe Puzzle: A Clue
The Puzzle: Solution
The 4th-floor hanger rods were found intact, with nuts and washers in place.
Hyatt Walkway CollapseThe Puzzle: Solution
The Puzzle: Solution
The 4th-floor box beams were separated at the ends, with the 2nd-floor hangers still in place.
Hyatt Walkway CollapseThe Puzzle: Solution
Hyatt Walkway Collapse – The Puzzle: Solution
Hyatt Failure Animation
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large animated
GIF file takes awhile
to load…
The Puzzle: Solution
The design change doubled the load on the 4th-floor box beams.
Original Design As-Built
Hyatt Walkway CollapseThe Puzzle: Solution
The Consequences
Engineer of record and project engineer had their Missouri professional engineering licenses revokedEngineering company lost its certificate of authority as an engineering firmMillions of dollars in damages awarded in civil cases brought by victims and their families
Hyatt Walkway CollapseThe Consequences
Design Improvements
Add more hanger rods and box beamsUse larger washersInstall bearing plates to move load to sides of box beams
Flip box beams back-to-back and use web stiffenersHyatt atrium now has one walkway supported by floor columns
Hyatt Walkway CollapseDesign Improvements
Tacoma Narrows Bridge Collapse1940 suspension bridge in Washington state
Location
Tacoma Bridge CollapseLocation
Location
Link between Olympic Peninsula and mainland
Tacoma Bridge CollapseLocation
Design
2800 ft center span
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
Tacoma Bridge CollapseDesign
Design
To reduce costs, sides constructed of solid 8-foot tall I-beams rather than typical open trusses
Tacoma Bridge CollapseDesign
Design
concrete sidewalk
two-lane concrete roadway
curb
I-beams
8 ft
39 ft
Tacoma Bridge CollapseDesign
Early Symptoms
Bridge nicknamed “Galloping Gertie” by drivers who would be startled as cars in front of them would bounce in and out of view.Engineers spent four months trying to reduce the vibrations.
Tacoma Bridge CollapseEarly Symptoms
Early Symptoms
Over several months, additions weremade to reduce deck bounce
Added stiffening cables
Added cable stays on sides, connecting main cable to deck
Added hydraulic dampers
Each would fail, one catastrophically
(snapped)
(seals ruined when bridgesandblasted for painting)
(one side slipped on day of collapse)
Tacoma Bridge CollapseEarly Symptoms
Wave medium moves perpendicular to direction of wave travel
Transverse Waves
Transverse waves
Nodes are where medium does not move
Antinodes are where the medium moves most
Tacoma Bridge CollapseEarly Symptoms
Transverse Waves
Gertie’s Transverse Wave Types
Towers were nodesVarious types: 0 to 8 nodes between towers
Most common type 0 nodes between
towers Double amplitude 2
feet Frequency 8
vibrations/min
Highest amplitude type 2 nodes between
towers Double amplitude 5
feet Frequency 12 vib/min
Tacoma Bridge CollapseEarly Symptoms
The Disaster
Midnight storm weakens bridge deck and cable stays
November 7, 1940(four months after opening)
Three people in two cars trapped on bridge as torsion began; they left cars and crawled to safety; one scared dog had to be left behind and later died when bridge fell.
Mid-morning wind reaches 40-45 mphBridge closed at 10 am and bridge begins torsional wave motion
Tacoma Bridge CollapseThe Disaster
Torsional Waves
Torsional (twisting) waves
Tacoma Bridge CollapseThe Disaster
Tacoma Bridge Collapse – The Disaster
Collapse Movie
Collapse Movie
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to load…
Tacoma Bridge CollapseThe Disaster
Center Span Breaks
11 am: Center span finally breaks apart
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file takes awhile
to load…
Tacoma Bridge CollapseThe Disaster
The Puzzle
Why did this bridge oscillate so much?
Why did this bridge fail when other, longer bridges didn’t?
What design changes might have prevented this failure?
Tacoma Bridge CollapseThe Puzzle
Oscillation
Solid I-beam girders, unlike trusses, did not allow wind to flow throughFlexible bridge oscillated vertically (transverse waves) due to vertical forces from “vortex shedding” as wind flowed around side girders
Why did this bridge oscillate so much?
Tacoma Bridge CollapseThe Puzzle
Oscillation
Torsional waves began when center cable stays on one side failed, allowing cable to slip back and forth
As bridge deck tilted, its angle into the wind changed and created new vortices that steadily increased its twisting until failure
Why did this bridge oscillate so much?
Tacoma Bridge CollapseThe Puzzle
Depth Ratios
This shallow bridge was more flexible than other suspension bridges of the time
Why did this bridge fail when other, longer bridges didn’t?
Bridge Depth/Span RatioTacoma Narrows 8 ft / 2800 ft 1 : 350
Bronx-Whitestone
11 ft / 2300 ft 1 : 209
Golden Gate 25 ft / 4200 ft 1 : 168
George Washington
36 ft / 3500 ft 1 : 97
Tacoma Bridge CollapseThe Puzzle
Width Ratios
This bridge was also narrow, again making it more flexible than
others
Why did this bridge fail when other, longer bridges didn’t?
Bridge Width/Span RatioTacoma Narrows 39 ft / 2800 ft 1 : 72
Bronx-Whitestone
74 ft / 2300 ft 1 : 31
Golden Gate 89 ft / 4200 ft 1 : 47
George Washington
106 ft / 3500 ft
1 : 33
Tacoma Bridge CollapseThe Puzzle
Deflection Comparisons
More Vertical Deflection
Why did this bridge fail when other, longer bridges didn’t?
More Torsional Deflection
Tacoma Bridge CollapseThe Puzzle
Design Changes
What design changes might have prevented this failure?
Use open trusses instead of I-beamsIncrease depth/span & width/span ratiosIncrease bridge weightInstall better dampeners
Bridge rebuilt in 1950 with these changes; new bridge has lasted >50 years
Tacoma Bridge CollapseThe Puzzle
New Bridge Comparison
What design changes might have prevented this failure?
Old bridge New bridgeDeck design Solid I-beams Open trusses
Depth/span ratio
1 : 350 1 : 112
Width/span ratio
1 : 72 1 : 47
Bridge weight on cables
11,250 tons(1.0 x 108 N)
18,160 tons(1.6 x 108 N)
Hydraulic Dampers
At towers (broken)
At towers & midspan
Tacoma Bridge CollapseThe Puzzle
New Bridge Comparison
What design changes might have prevented this failure?
1940 Bridge 1950 Bridge
Tacoma Bridge CollapseThe Puzzle
Comparison Photos
Old vs. New
Tacoma Bridge CollapseThe Puzzle
Comparison Photos
Old vs. New
Tacoma Bridge CollapseThe Puzzle
2007 BridgeTacoma Bridge CollapseIn 2007 a new bridge opened adjacent to the 1950 bridgeto alleviate traffic congestion.
References 1
References (1 of 6 pages) USED IN ACCORDANCE WITH “FAIR USE”
PROVISIONS OF COPYRIGHT LAW FORNON-PROFIT EDUCATIONAL PURPOSES
Andradne, R. (2000). Gertie’s last gallop [Online]. Available: http://www.gateline.com/gertie/index.htm or http://www.gateline.com/gertie/Galloping%20Gertie.zip [2001, January 27].
Billah, K.Y., & Scanlan, R.H. (1991, February). Resonance, Tacoma Narrows bridge failure, and undergraduate physics textbooks. American Journal of Physics, 59(2), 118-124. Available: http://www.ketchum.org/billah/Billah-Scanlan.pdf [2001, January 27].
Edge, R. (1998). String and sticky tape - and other fun experiments [Online]. Proceedings of the Hands on - Experiments in Physics Education International Conference. Duisburg, Germany. Available: http://ubntint.uni-duisburg.de/hands-on/files/autoren/edge/edge.htm [February 8, 2001].
Elliot, E. (undated). Tacoma Narrows bridge video [Online]. Available: http://www.camerashoptacoma.com/narrows.asp [2001, February 4].
Expedia, Inc. (2000). Tacoma, Washington [Online map]. Available: http://maps.expedia.com/pub/agent.dll [2001, February 10].
Exponent, Inc. (undated). Hyatt walkway collapse [QuickTime Video; Online]. Available: http://www.exponent.com/multimedia/cases/hyatt.html [2001, January 27].
Failure By Design
References 2
References (2 of 6 pages)
Fuller, R.G., Lang, C.R., & Lang, R.H. (2000). Twin views of the Tacoma Narrows bridge collapse. College Park, MD: American Association of Physics Teachers [http://www.aapt.org].
Gies, J. (1963). Bridges and men. Garden City, NY: Doubleday.
Groutt, P. (1996). University of Maryland physics lecture-demonstration facility [Online]. Available: http://jedlik.phy.bme.hu/~hartlein/physics.umd.edu/deptinfo/facilities/lecdem/lecdem.htm#hp[2001, February 8].
Hanley-Wood LLC. (2000). Q&A: squash blocks and web stiffeners [Online]. Available: http://www.jlconline.com/jlc/qana/framing/squash_blocks/ [2001, February 10].
Harris, C.E. & Rabins, M.J. (1992). Engineering ethics: The Kansas City Hyatt Regency walkways collapse (NSF Grant Number DIR-9012252) [original version of Lowery (1999) online document]. College Station, TX: Texas A&M University, Department of Philosophy and Department of Mechanical Engineering.
Institute for Structural Analysis. (1997). Tacoma Narrows Bridge (1940) failure [Online]. Available: http://www.cis.tugraz.at/ifb/img/others/tacoma/tacoma.htm [2001, January 28].
James, M.N. (undated). Failure as a design criterion [Online]. Available: http://www.tech.plym.ac.uk/sme/FailureCases/Failure.htm [2001, February 5].
Jensen, J.N. (2000). Civil engineering case study [Online]. Available: http://www.acsu.buffalo.edu/~jjensen/cie.htm [2001, February 17].
Failure By Design
References 3
References (3 of 6 pages)
Ketchum, M. (undated). Mark Ketchum’s bridge engineering page [Online]. Available: http://www.ketchum.org/bridges.html [2001, February 8].
Koughan, J. (1996). The collapse of the Tacoma Narrows bridge, evaluation of competing theories of its demise, and the effects of the disaster on succeeding bridge designs [Online]. Available: http://www.me.utexas.edu/~uer/papers/paper_jk.html [2001, January 27].
Lank, S., Robinson, M., Sevigny, S., Steger, M., & Tsai, J. (1997). Smash and crash: The Kansas City Hyatt Regency walkway collapse [Online]. Available: http://www.people.virginia.edu/~jtt3e/hyatt/paper.htm [2001, February 17].
Lou, B. (undated). Bridge and resonance [Online]. Available: http://instruction.ferris.edu/loub/media/BRIDGE/Bridge.htm [2001, February 4].
Lowery, L. (1999). Engineering ethics: The Kansas City Hyatt Regency walkways collapse [Online]. Available: http://lowery.tamu.edu/ethics/ethics/hyatt/hyatt1.htm and http://lowery.tamu.edu/ethics/ethics/hyatt/hyatt2.htm [2001, January 28].
Martin, R. (1999a). Hyatt Regency walkway collapse [Online]. Available: http://www.eng.uab.edu/cee/REU_NSF99/hyatt.htm [2001, January 28].
Martin, R. (1999b). Tacoma Narrows bridge collapse [Online]. Available: http://www.eng.uab.edu/cee/REU_NSF99/tacoma.htm [2001, January 28].
Failure By Design
References 4
References (4 of 6 pages)
Meador, G. (1997). Activity #2: Slinky waves [Online]. Available: http://www.teachingtools.com/SlinkyShindig/activ2.html [2001, February 8].
Moore, K.S. (1999). Large amplitude torsional oscillations in a nonlinearly suspended beam: A theoretical and numerical investigation [Online]. Available: http://www.math.lsa.umich.edu/~ksmoore/ [2001, February 4].
Neyman, P. (undated). Torsion wave representation [Online]. Available: http://sps1.phys.vt.edu/~pat-man/LiNC/movies/torsion.mov [2001, February 5].
Petroski, H. (1985). To engineer is human: The role of failure in successful design. New York: St. Martin’s Press. Available for purchase at: http://www.amazon.com/exec/obidos/ASIN/0679734163
Petroski, H. (1994). Design paradigms: Case histories of error and judgment in engineering. New York: Cambridge University Press. Available for purchase at: http://www.amazon.com/exec/obidos/ASIN/0521466490
Rogers, K. (1997). The Tacoma Narrows bridge disaster [Online]. Available: http://137.142.19.40/seconded/second/Kent/Kent.html [February 8, 2001].
Russell, D. (2000). Vibration and wave animations [Online]. Available: http://www.kettering.edu/~drussell/Demos.html [2001, February 4].
Failure By Design
References 5
References (5 of 6 pages)
Scott, S. (undated). Tacoma Narrows bridge [Online]. Available: http://people.mn.mediaone.net/sscott2/Text_Files/gertie.html [2001, February 8].
Smith, D. (1974, March 29). A case study and analysis of the Tacoma Narrows Bridge failure [Online]. Unpublished manuscript, Carleton University, Department of Mechanical Engineering, Ottawa, Canada. Available: http://www.civeng.carleton.ca/Exhibits/Tacoma_Narrows/DSmith/photos.html [2001, February 7].
Tan, B.T., Thompson, M.C., & Hourigan, K. (1998). Simulated Flow around Long Rectangular Plates under Cross Flow Perturbations [Online]. International Journal of Fluid Dynamics, 2(1). Available: http://sibley.mae.cornell.edu/IJFD/1998_vol2/paper1/paper1.html [2001, February 8].
Underwater Atmospheric Systems. (undated). Tacoma Narrows bridge [Online]. Available: http://www.nwrain.com/~newtsuit/recoveries/narrows/narrows.htm [2001, February 8].
United States Geological Survey. (1992, May 13). Tacoma, Washington, United States [Online image]. Available: http://terraserver.microsoft.com/image.asp?S=14&T=1&X=168&Y=1635&Z=10&W=2 [2001, February 10].
Failure By Design
References 6
References (6 of 6 pages)
Washington State Department of Transportation. (2008). SR 16 - New Tacoma Narrows Bridge [Online]. Available: http://www.wsdot.wa.gov/projects/sr16narrowsbridge/ [2008, March 6].
Washington State Department of Transportation. (2007a). NTPAW Tacoma Narrows Bridge Tour [Online image]. Available: http://www.flickr.com/photos/wsdot/1129855059/ [2008, March 6].
Washington State Department of Transportation. (2007b). View from the Top [Online image]. Available: http://www.flickr.com/photos/wsdot/829349869/ [2008, March 6].
The author thanks the Exponent engineering company (http://www.exponent.com) and its webmaster for agreeing to provide their animation of the Hyatt Regency walkway collapse.
Failure By Design
www.failurebydesign.info
Inquiry Physics
www.inquiryphysics.org
All images used under the “educational fair use” provisions of copyright law.
This presentation is Creative Commons licensed for free distribution for non-commercial use when attributed to Granger Meador