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Failure By Design www.failurebydesign.info Inquiry Physics www.inquiryphysics.org.

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Presentation on theme: "Failure By Design www.failurebydesign.info Inquiry Physics www.inquiryphysics.org."— Presentation transcript:

1 Failure By Design Inquiry Physics

2 Purpose Tacoma Narrows Bridge Collapse Examine different types of wave motion and how aerodynamic effects destroyed a structure Hyatt Hotel Walkway Collapse Use your analytical and deductive skills to speculate about what caused a structural disaster

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

4 The Disaster Atrium crowded with people for a dance competition Second and fourth-floor walkways collapsed 114 people killed, over 200 injured July 17, 1981 (one year after opening) Hyatt Walkway Collapse The Disaster

5 The Disaster 2 nd- floor walkway designed to hang from 4 th -floor walkway, which was hung from roof by three rods along each side of its 117 ft (36 m) length 3 rd floor walkway was separate and survived Hyatt Walkway Collapse The Disaster

6 The Puzzle Since both the 4 th and 2 nd floor walkways fell, which parts of the walkways could have failed? Hyatt Walkway Collapse The Puzzle

7 The Puzzle What evidence would you look for to decide which part did fail? Hyatt Walkway Collapse The Puzzle

8 Hyatt Walkway Collapse – The Puzzle Hyatt Design Animation Please be patient…large animated GIF file takes awhile to load…

9 The Puzzle Have you decided which part most likely failed? Next is an important clue. Hyatt Walkway Collapse The Puzzle

10 The Puzzle: A Clue Design Change Original design used single rods to support both walkways, but they would have been awkward to install and thread. Each rod would have connected to 4 th -floor walkway as shown. Hyatt Walkway Collapse The Puzzle: A Clue

11 The Puzzle: A Clue Design Change As-built, the single long rods were replaced by a pair of shorter rods connecting to the 4 th -floor walkway as shown. Hyatt Walkway Collapse The Puzzle: A Clue

12 Hyatt Walkway Collapse – The Puzzle: A Clue Hyatt Design Change

13 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 Collapse The Puzzle: A Clue

14 The Puzzle: Solution The 4 th -floor hanger rods were found intact, with nuts and washers in place. Hyatt Walkway Collapse The Puzzle: Solution

15 The Puzzle: Solution The 4 th -floor box beams were separated at the ends, with the 2 nd -floor hangers still in place. Hyatt Walkway Collapse The Puzzle: Solution

16 Hyatt Walkway Collapse – The Puzzle: Solution Hyatt Failure Animation Please be patient…large animated GIF file takes awhile to load…

17 The Puzzle: Solution The design change doubled the load on the 4 th -floor box beams. Original DesignAs-Built Hyatt Walkway Collapse The Puzzle: Solution

18 The Consequences Engineer of record and project engineer had their Missouri professional engineering licenses revoked Engineering company lost its certificate of authority as an engineering firm Millions of dollars in damages awarded in civil cases brought by victims and their families Hyatt Walkway Collapse The Consequences

19 Design Improvements Add more hanger rods and box beams Use larger washers Install bearing plates to move load to sides of box beams Flip box beams back-to-back and use web stiffeners Hyatt atrium now has one walkway supported by floor columns Hyatt Walkway Collapse Design Improvements

20 Tacoma Narrows Bridge Collapse 1940 suspension bridge in Washington state

21 Location Tacoma Bridge Collapse Location

22 Location Link between Olympic Peninsula and mainland Tacoma Bridge Collapse Location

23 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 Collapse Design

24 Design To reduce costs, sides constructed of solid 8-foot tall I-beams rather than typical open trusses Tacoma Bridge Collapse Design

25 Design concrete sidewalk two-lane concrete roadway curb I-beams 8 ft 39 ft Tacoma Bridge Collapse Design

26 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 Collapse Early Symptoms

27 Early Symptoms Over several months, additions were made 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 bridge sandblasted for painting) (one side slipped on day of collapse) Tacoma Bridge Collapse Early Symptoms

28 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 Collapse Early Symptoms

29 Transverse Waves Gerties Transverse Wave Types Towers were nodes Various 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 Collapse Early Symptoms

30 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 mph Bridge closed at 10 am and bridge begins torsional wave motion Tacoma Bridge Collapse The Disaster

31 Torsional Waves Torsional (twisting) waves Tacoma Bridge Collapse The Disaster

32 Tacoma Bridge Collapse – The Disaster Collapse Movie Please be patient…large animated GIF file takes awhile to load… Tacoma Bridge Collapse The Disaster

33 Center Span Breaks 11 am: Center span finally breaks apart Please be patient…large animated GIF file takes awhile to load… Tacoma Bridge Collapse The Disaster

34 The Puzzle 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? Tacoma Bridge Collapse The Puzzle

35 Oscillation 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 Why did this bridge oscillate so much? Tacoma Bridge Collapse The Puzzle

36 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 Collapse The Puzzle

37 Depth Ratios This shallow bridge was more flexible than other suspension bridges of the time Why did this bridge fail when other, longer bridges didnt? BridgeDepth/SpanRatio Tacoma Narrows8 ft / 2800 ft1 : 350 Bronx-Whitestone11 ft / 2300 ft1 : 209 Golden Gate25 ft / 4200 ft1 : 168 George Washington36 ft / 3500 ft1 : 97 Tacoma Bridge Collapse The Puzzle

38 Width Ratios This bridge was also narrow, again making it more flexible than others Why did this bridge fail when other, longer bridges didnt? BridgeWidth/SpanRatio Tacoma Narrows39 ft / 2800 ft1 : 72 Bronx-Whitestone74 ft / 2300 ft1 : 31 Golden Gate89 ft / 4200 ft1 : 47 George Washington106 ft / 3500 ft1 : 33 Tacoma Bridge Collapse The Puzzle

39 Deflection Comparisons More Vertical Deflection Why did this bridge fail when other, longer bridges didnt? More Torsional Deflection Tacoma Bridge Collapse The Puzzle

40 Design Changes What design changes might have prevented this failure? Use open trusses instead of I-beams Increase depth/span & width/span ratios Increase bridge weight Install better dampeners Bridge rebuilt in 1950 with these changes; new bridge has lasted >50 years Tacoma Bridge Collapse The Puzzle

41 New Bridge Comparison What design changes might have prevented this failure? Old bridgeNew bridge Deck designSolid I-beamsOpen trusses Depth/span ratio1 : 3501 : 112 Width/span ratio1 : 721 : 47 Bridge weight on cables 11,250 tons (1.0 x 10 8 N) 18,160 tons (1.6 x 10 8 N) Hydraulic Dampers At towers (broken) At towers & midspan Tacoma Bridge Collapse The Puzzle

42 New Bridge Comparison What design changes might have prevented this failure? 1940 Bridge1950 Bridge Tacoma Bridge Collapse The Puzzle

43 Comparison Photos Old vs. New Tacoma Bridge Collapse The Puzzle

44 Comparison Photos Old vs. New Tacoma Bridge Collapse The Puzzle

45 2007 Bridge Tacoma Bridge Collapse In 2007 a new bridge opened adjacent to the 1950 bridge to alleviate traffic congestion.

46 References 1 References (1 of 6 pages)USED IN ACCORDANCE WITH FAIR USE PROVISIONS OF COPYRIGHT LAW FOR NON-PROFIT EDUCATIONAL PURPOSES Andradne, R. (2000). Gerties last gallop [Online]. Available: or [2001, January 27].http://www.gateline.com/gertie/index.htm Billah, K.Y., & Scanlan, R.H. (1991, February). Resonance, Tacoma Narrows bridge failure, and undergraduate physics textbooks. American Journal of Physics, 59(2), Available: [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: [February 8, 2001]. Elliot, E. (undated). Tacoma Narrows bridge video [Online]. Available: [2001, February 4]. Expedia, Inc. (2000). Tacoma, Washington [Online map]. Available: [2001, February 10].http://maps.expedia.com/pub/agent.dll Exponent, Inc. (undated). Hyatt walkway collapse [QuickTime Video; Online]. Available: [2001, January 27]. Failure By Design

47 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].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: February 8]. Hanley-Wood LLC. (2000). Q&A: squash blocks and web stiffeners [Online]. Available: [2001, February 10]. Harris, C.E. & Rabins, M.J. (1992). Engineering ethics: The Kansas City Hyatt Regency walkways collapse (NSF Grant Number DIR ) [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: [2001, January 28]. James, M.N. (undated). Failure as a design criterion [Online]. Available: [2001, February 5]. Jensen, J.N. (2000). Civil engineering case study [Online]. Available: [2001, February 17]. Failure By Design

48 References 3 References (3 of 6 pages) Ketchum, M. (undated). Mark Ketchums bridge engineering page [Online]. Available: [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: [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: [2001, February 17].http://www.people.virginia.edu/~jtt3e/hyatt/paper.htm Lou, B. (undated). Bridge and resonance [Online]. Available: [2001, February 4]. Lowery, L. (1999). Engineering ethics: The Kansas City Hyatt Regency walkways collapse [Online]. Available: and [2001, January 28]. Martin, R. (1999a). Hyatt Regency walkway collapse [Online]. Available: [2001, January 28]. Martin, R. (1999b). Tacoma Narrows bridge collapse [Online]. Available: [2001, January 28]. Failure By Design

49 References 4 References (4 of 6 pages) Meador, G. (1997). Activity #2: Slinky waves [Online]. Available: [2001, February 8]. Moore, K.S. (1999). Large amplitude torsional oscillations in a nonlinearly suspended beam: A theoretical and numerical investigation [Online]. Available: [2001, February 4].http://www.math.lsa.umich.edu/~ksmoore/ Neyman, P. (undated). Torsion wave representation [Online]. Available: man/LiNC/movies/torsion.mov [2001, February 5].http://sps1.phys.vt.edu/~pat- man/LiNC/movies/torsion.mov Petroski, H. (1985). To engineer is human: The role of failure in successful design. New York: St. Martins Press. Available for purchase at: Petroski, H. (1994). Design paradigms: Case histories of error and judgment in engineering. New York: Cambridge University Press. Available for purchase at: Rogers, K. (1997). The Tacoma Narrows bridge disaster [Online]. Available: [February 8, 2001]. Russell, D. (2000). Vibration and wave animations [Online]. Available: [2001, February 4]. Failure By Design

50 References 5 References (5 of 6 pages) Scott, S. (undated). Tacoma Narrows bridge [Online]. Available: [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: [2001, February 7].http://www.civeng.carleton.ca/Exhibits/Tacoma_Narrows/DSmith/photos.html 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: [2001, February 8]. Underwater Atmospheric Systems. (undated). Tacoma Narrows bridge [Online]. Available: [2001, February 8]. United States Geological Survey. (1992, May 13). Tacoma, Washington, United States [Online image]. Available: [2001, February 10]. Failure By Design

51 References 6 References (6 of 6 pages) Washington State Department of Transportation. (2008). SR 16 - New Tacoma Narrows Bridge [Online]. Available: [2008, March 6]. Washington State Department of Transportation. (2007a). NTPAW Tacoma Narrows Bridge Tour [Online image]. Available: [2008, March 6]. Washington State Department of Transportation. (2007b). View from the Top [Online image]. Available: [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.http://www.exponent.com Failure By Design

52 Inquiry Physics 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


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