Similar Bridge Collapses
The Tacoma Narrows bridge collapse, 1940.
photo credit: Library of Congress, DIGID http://hdl.loc.gov/loc.pnp/hhh.wa0453
The 35W Bridge collapse reminded us that bridges do fail, even ones we think are modern or trustworthy. However, the 35W bridge collapse was unique. Most United States bridge failures (53%) are a result of flood or scour (1). Other common causes of collapse are overload or collisions with trucks, trains, ships, and barges. It is relatively rare that a United States bridge has actually collapsed due to a structural defect. Chronological information about similar bridge collapses in United States History can be found below.
Although each bridge had a different design and collapsed due to the failure of a different element, all of the bridges examined here had common features contributing to their failure. The bridges tended to have structures that were not redundant. Nonredundant structures cause a partial collapse to progress to a total collapse because each component of the bridge is intricately linked to the others. Bridge design has changed as a result of these past failures. Engineers and designers now utilize redundancy in their plans. Then, if part of the span fails, a collapse can potentially be avoided, or at least a smaller portion of the bridge is affected rather than the whole.
The collapsed bridges also had critical features that either could not be inspected or were not inspected (2). As a result of these collapses, modern bridge design ensures that critical features are visible and testable in an inspection. The need for regular, effective inspection has also been recognized, although resources may limit the extent to which United States bridges are, in fact, inspected.
The resulting changes to policy after each bridge collapse illustrate Lichtenstein's "Pendulum Principle." Bridge expert Abba Lichtenstein has more than 45 years of experience in the design, inspection, and rating of bridges (3). He helped develop national standards for the inspection and rating of all types of bridges, and was principal investigator for the research that led to revisions to the American Association of State Highway and Transportation Officials’ Manual for the Condition Evaluation of Highway Bridges (3). In Abba Lichtenstein's recounting of the Silver Bridge collapse, he described the basis of the "pendulum principle":
A dramatic collapse of a certain type of bridge is followed by a period of intense research activity. Engineering resources and energies are mobilized to investigate, explain, and litigate the accident. Federal and state agencies, universities, and other research organizations swing into action with full force to study the cause of failure and find remedies. Eventually, new specifications and methods of bridge design and inspection are produced by this accelerated research, and they become the state of the art of the industry. The bridge community then normalizes and watches for the next occasion to move into action and absorb the results of the next unexpected bridge failure (4).
To learn more about the structural causes of the 35W collapse, visit Structural Causes of the Collapse.
To learn about bridge collapses worldwide from all causes, visit Bridge Collapses.
Ashtabula River Railroad Disaster
December 29, 1876
Ashtabula, Ohio
During the aftermath of this collapse, the media began referring to it as the "Ashtabula Horror." At 7:28 PM, December 29, 1876, the double track railroad bridge over Ashtabula Creek (Ashtabula, Ohio) failed. The collapse occured as a Lake Shore and Michigan Southern Railway train crossed the double track bridge. This collapse occurred during a snowstorm that dumped two feet of snow onto the tracks and produced 40 mph winds. Train no. 5, The Pacific Express, was traveling with two locomotives, eleven railcars, and 159 passengers and crew. Of the 159 on board, 64 were injured and 92 died, 48 unrecognized. The first locomotive, The Socrates, made it across the bridge and was the only part of the train that did not drop 60 feet into the crevice below.
Lake Shore and Michigan Southern Railway lost $495,722 due to the bridge collapse (5). The 150 foot span of the bridge was made of iron and spanned the crevice on a Howe Truss between two abutments. The bridge was built over a two year period spanning from 1863 to 1865. It collapsed after 11 years of use. After the collapse, the Ohio State Legislature appointed an investigating committee to determine the cause of the collapse. Eventually the failure was attributed to fatigue and inadequate inspection. The collapse had a lasting impact on bridge constuction and inspection. Governmental policymakers soon realized that there was a need for standard bridge specifications, for qualified consulting engineers, and for an evaluation of the reliability of iron castings (2).
To learn more about the Ashtabula Horror, visit Ashtabula River Railroad Disaster.
Tacoma Narrows Bridge
November 7, 1940
Tacoma, WA
While officially named the Tacoma Narrows Bridge, it was more commonly referred to as "Galloping Gertie." The design for the Tacoma Narrows Bridge (Tacoma, WA) utilized a slim, elegant design using plate girders instead of lattice beam trusses and was the third longest suspension bridge in the world when completed. The design type meant wind had to part up and down to pass the bridge instead of flowing through the lattice roadbed. As soon as the bridge construction was complete, engineers discovered that the bridge would sway and buckle in mild winds. As cars drove over the bridge, the road would rise and fall, creating hills and valleys in a transverse resonance mode, leading to the nickname Galloping Gertie. Because it had such a large mass engineers considered the bridge safe, despite the bridge's movement (2).
On November 7, 1940 a new type of resonance movement was seen during 40 mile per hour winds, transverse movement. This type of wave movement caused the sides of the bridge to alternately rise and fall with greater and greater height, until the sidewalks on either side were 28 feet apart in height. Finally, the cables failed and the entire midspan fell into the Tacoma narrows. No fatalities occured as nearly all the cars had been cleared off the bridge when the oscillations started. One dog, "Tubby" was a casualty of the collapse as he was too afraid to get out of the car, and bit one person who tried to rescue him. The collapse was caught on color Kodachrome film and the sunken remains are listed on the National Register of Historic Places.
To learn more about the Tacoma Narrows collapse, visit Tacoma Narrows Bridge Collapse.
Silver Bridge Collapse
December 15, 1967
Point Pleasant, WV
The Silver Bridge, also referred to as the Point Pleasant Bridge, connected Point Pleasant, West Virginia with Kanauga, Ohio across the Ohio River. At 5:00 PM, December 15, 1967 the bridge suddenly collapsed. In one minute the 700 foot center span, the two 380 foot side spans, and the support towers all collapsed. Of 37 vehicles on the bridge at the time of the collapse, 31 fell resulting in 46 fatalities and 9 injuries.
The Silver Bridge was an eyebar suspension bridge, an unusual bridge design. After the collapse, a major design flaw was found: lack of redundancy. Each piece of the bridge was intricately linked to the others and the failure of one component then resulted in the failure of the whole bridge. The cause of the collapse was found to be a cleavage fracture (across the grain of the material) in the lower limb of an eyebar, causing the separation of the eyebar from its chain, allowing the sister eyebar to slide off. Failure at this eyebar caused the failure of the entire structure. This collapse resulted in the development of a national bridge inspection and replacement program (2).
To learn more about the silver bridge collapse, visit Silver Bridge Collapse.
Mianus River Bridge
June 28, 1983
Greenwich, CT
At 1:30 AM, June 28, 1983 the Mianus River bridge in Greenwich, Connecticut failed after 25 years of use. A 100 foot span, weighing 500 tons, fell 70 feet into the river below. Two tractor-trailers and two cars fell, resulting in 3 deaths and 3 serious injuries. The timing of the collapse prevented more deaths and injuries from occuring because there were few people on the usually crowded bridge.
The bridge design had a skewed simple span, supported at each corner by pin and hanger asemblies, held in place by thin locking caps. The cause of the collapse was a hanger pin failure due to corrosion. The storm drains on the bridge had purposefully been paved over 10 years prior during bridge maintenance. The lack of drainage caused the locking cap corrosion and subsequent failure. The collapse resulted in the reopening of storm drains on the rest of the bridge and similar bridges and called into question the level and methods of bridge inspection.
To learn more about the Mianus River bridge collapse, visit Mianus River Bridge Collapse.
Schoharie Creek Thruway Bridge
April 5, 1987
Fort Hunter, NY
The Schoharie Creek thruway bridge near Fort Hunter, New York collapsed during a near record flood April 5, 1987, after 33 years of use. Six inches of rain combined with snow melt to create a 50 year flood. The bridge design was five simple support spans connected by concrete pier frames. Pier three collapsed resulting in spans three and four falling into the flooded creek. Five vehicles fell into the water: one car and one tractor-trailer that were on the bridge and three cars that drove into the gap. Pier two and span two fell 90 minutes later. Ten deaths resulted and all but one body was recovered.
A 100 year flood occured the year after the bridge opened in 1954. The bridge survived that flood, but the damage done may have had an impact on the eventual collapse (2). The cause of the failure was later attributed to excessive scour at the bases of the piers, resulting from compromised scour protection, and the collapse resulted in accelerated research into scour (6) . After the collapse, the Federal Highway Administration required states to identify bridges likely to have scour problems and bridges where scour was known to be severe.
To learn more about the Schoharie Creek Thruway Bridge collapse, visit Schoharie Creek Thruway Bridge Collapse.
Tennessee Hatchie River Bridge
April 1, 1989
Covington, Tennessee
On April 1, 1989 a 60 foot section of the Hatchie River bridge for State Highway 51 in Covington, Tennessee, collapsed into the river below. The river was bloated with rainwater and was 2.7 feet above the twelve foot flood level. Four cars and one tractor-trailer fell 25 feet into the river and all the vehicle occupants died, resulting in eight deaths. The bridge was 50 years old.
Federal investigation found that the river channel had moved 83 feet since the bridge was constructed in 1936 and that the failure was a result of deteriorating timber piles underwater which had originally been buried. After the Hatchie River bridge collapse, Tennessee started sending divers underwater every five years to check for structural problems. The National Traffic Safety Board faulted Tennessee for not fixing problems with the bridge ten years earlier (7).
To learn more about the Hatchie River bridge collapse, visit Hatchie River Bridge Collapse.
References
1. Thorton, C.H., Tomasetti, R.L., & Joseph, L.M. (1988). Lessons from schoharie creek. Civil Engineering, 58(5), 46-49.
2. Delatte, N. (2007). Maintenance and management lessons learned from bridge collapses. Prepared for the Transportation Research Board Annual Meeting. Paper #07-2306.
3. "Deen Lecture 85th Annual Meeting Press Release" (2006). Retrieved May 1, 2008, from trb.org/am/news/2006PR/Deen.pdf.
4. Lichtenstein, A. (1993). The silver bridge collapse recounted. Journal of Performance of Constructed Facilities, 7(4), 249-261.
5. "Corporate Stockholder Report" (1877). Lake Shore and Michigan Southern Railway. Retrieved May 1, 2008, from http://home.alltel.net/arhf/bridge.htm.
6. "Collapse of New York Thruway (I-90) bridge over the Schoharie Ckeek, near Amsterdam, New York, April 5, 1987" (1987). National Transportation Safety Board (NTSB).
Highway Accident Report: NTSB/HAR-88/02, Washington, D.C.
7. Associated Press (1990). Tennessee is faulted in collapse of bridge. New York Times. Retrieved May 5, 2008, from http://query.nytimes.com/gst/fullpage.html?res=9C0CE2D6143BF935A35755C0A966958260.