Progressive collapse

A building undergoes progressive collapse when a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failure.[1]

Initiating factors behind notable examples

Ronan Point, following the gas explosion.

Terminology

Since the resulting damage in a progressive collapse is disproportionate to the original cause, the term disproportionate collapse is frequently used in engineering to describe this collapse type.

The first date-recorded instance of the term pancake collapse being published in lieu of "progressive collapse" occurred in the August 10, 1980, edition of the New York Times. Fire Chief John Connelly of the 19th Battalion explained that the apartment building, which they responded to in the Bronx, had been weakened by fire to the point that all floors had begun to pancake down on one another. "'It was a pancake collapse.' said Chief John Connelly of the 19th Battalion. 'The entire building was flaming and it went down to the ground.'"[21]

Model code changes

Based on recommendations from the Commerce Department's National Institute of Standards and Technology (NIST), a comprehensive set of building code changes were approved by the International Code Council (ICC). The recommendations were based on the findings of NIST's three-year investigation of the collapses of New York City's World Trade Center (WTC) towers on Sept. 11, 2001.

The proposals addressed areas such as increased resistance to building collapse from fire and other incidents, use of sprayed fire-resistive materials (commonly known as "fireproofing"), performance and redundancy of fire protection systems (i.e., automatic sprinklers), fuel oil storage/piping, elevators for use by first responders and evacuating occupants, the number and location of stairwells, and exit path markings.

The model code changes consistent with the NIST WTC investigation recommendations that are now required by the IBC include:

See also

References

  1. Ellingwood, B. R.; Leyendecker, E. V. (1978). "Approaches for design against progressive collapse". Journal of the Structural Division 104 (3): 413–423. A progressive collapse is a chain reaction type of failure which follows damage to a relatively small portion of a structure.
  2. A study on St. Mark's Campanile can be found in Northwestern Universities civil engineering archive and a study about the effects of aging on ancient medieval bell towers was released by the University of Pisa in 2001.
  3. An engineering overview on the collapse with articles from The Scotsman is available. An article on the collapse can also be found in The St. Petersburg Times as well as in the Hansard Archives HERE and HERE
  4. Although certain articles claim the building was a 21-story building and others claim it to be a 22-story building, the ultimate height of the building was attained by looking up renter addresses for "1000 Wilshire Blvd 22nd Floor" There are renter addresses listed up to the 22nd floor but not higher
  5. 1000 Wilshire Blvd. Los Angeles, CA 90017 was named the Wedbush Building in January 2002
  6. The location of the office building was at 1000 Wilshire Blvd. in Los Angeles and consisted of a 5 floor collapse
  7. A documentary about the Hotel New World collapse is available on YouTube
  8. The L'Ambiance Plaza case can be found on Engineering.com
  9. A study on Pavia Civic Tower can be found in Northwestern Universities civil engineering archive and a study about the effects of aging on ancient medieval bell towers was released by the University of Pisa in 2001.
  10. Reference to the church of St Maria Magdalena can be found in a study about the effects of aging on ancient medieval bell towers, which was released by the University of Pisa in 2001.
  11. A case study on the Kader Toy Factory fire is available.
  12. A documentary about the Murrah Federal Building collapse is available on YouTube. Note that the building floors in this documentary are referred to by British Convention and will thus be one floor less than the American name for each floor.
  13. The NIST has released a summary and a report on the bombing of the Alfred P. Murrah Federal Building and its collapse.
  14. A documentary about the Sampoong Department Store collapse is available on YouTube
  15. NIST has published a final report on the causes of the World Trade Center collapse.
  16. "Questions and Answers about the NIST WTC Towers Investigation". NIST. p. FAQ #8. Retrieved 3 May 2014. NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
  17. An engineering case study on the Windsor Tower Fire is available.
  18. http://www.telegraph.co.uk/news/worldnews/asia/bangladesh/10014778/Bangladesh-building-collapse-kills-at-least-82-in-Dhaka.html
  19. http://www.bbc.co.uk/news/world-asia-22394094
  20. David Blair, David Bergman (3 May 2013). "Bangladesh: Rana Plaza architect says building was never meant for factories". The Telegraph (London). Retrieved 8 May 2013.
  21. The full Pay-Per-View article on the Bronx fire is available through the New York Times

External links

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