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{{Use dmy dates|date=August 2022}}
{{more citations needed|date=July 2012}}
[[File:Hopfallen lada vid Hörsne Gotland Sverige.jpg|thumb|
[[File:Negaunee Bus Barn Collapse.jpg|thumb|
[[File:2025 Bangkok skyscraper collapse.png|thumb|A [[dashcam]]
'''Structural integrity and failure''' is an aspect of [[engineering]] that deals with the ability of a [[structure]] to support a designed [[structural load]] ([[weight]], [[force]], etc.) without breaking, and includes the study of past structural failures in order to prevent failures in future designs.
Structural integrity is the ability of an item—either a structural component or a structure consisting of many components—to hold together under a load, including its own weight, without breaking or deforming excessively. It assures that the construction will perform its designed function during reasonable use, for as long as its intended life span. Items are constructed with structural integrity to prevent [[catastrophic failure]], which can result in injuries, severe damage, death, and/or monetary losses.
''Structural failure'' refers to the loss of structural integrity, or the loss of [[Structural load|load]]-carrying structural capacity in either a structural component or the [[Architectural structure|structure]] itself. Structural failure is initiated when a [[List of building materials|material]] is stressed beyond its [[Strength of materials|strength]] limit, causing fracture or excessive [[Deformation (engineering)|deformations]]; one [[Limit state design|limit state]] that must be accounted for in structural design is ultimate failure strength. In a well
==Introduction==
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To construct an item with structural integrity, an engineer must first consider a material's mechanical properties, such as [[toughness]], [[Strength of materials|strength]], weight, [[hardness]], and elasticity, and then determine the size and shape necessary for the material to withstand the desired load for a long life. Since members can neither break nor bend excessively, they must be both stiff and tough. A very stiff material may resist bending, but unless it is sufficiently tough, it may have to be very large to support a load without breaking. On the other hand, a highly elastic material will bend under a load even if its high toughness prevents fracture.
Furthermore, each component's integrity must correspond to its individual application in any load-bearing structure. Bridge supports need a high [[yield strength]], whereas the bolts that hold them need good [[Shear strength|shear]] and [[tensile strength]]. [[Spring (device)|Springs]] need good [[Elasticity (physics)|elasticity]], but [[lathe]] tooling needs high rigidity. In addition, the entire structure must be able to support its load without its weakest links failing, as this can put more stress on other structural elements and lead to [[cascading failure]]s.<ref>''Introduction to Engineering Design: Modelling, Synthesis and Problem Solving Strategies'' By Andrew E. Samuel, John Weir – Elsevier 1999 Page 3—5</ref><ref>''Structural Integrity of Fasteners, Volume 2'' Edited by Pir M. Toor – ASTM 2000</ref>
==History==
[[File:Meidoum03.jpg|thumb|The Pyramid at [[Meidum]] was the second built by the [[ancient Egyptians]] around 2600 BC. It suffered from many structural defects, causing it to collapse during construction and leaving the inner core standing in a pile of rubble, which provided one of the earliest known lessons in large-scale building.]]
The need to build structures with integrity goes back as far as [[recorded history]]. Houses needed to be able to support their own weight, plus the weight of the inhabitants. Castles needed to be fortified to withstand assaults from invaders. Tools needed to be strong and tough enough to do their jobs.
In ancient times there were no mathematical formulas to predict the integrity of a structure. Builders, blacksmiths, carpenters, and masons relied on a system of trial and error (learning from past failures), experience, and apprenticeship to make safe and sturdy structures. Historically, safety and longevity were ensured by overcompensating, for example, using 20 tons of concrete when 10 tons would do. [[Galileo Galilei]] was one of the first to take the strength of materials into account in 1638, in his [[treatise]] ''Dialogues of Two New Sciences''. However, mathematical ways to calculate such material properties did not begin to develop until the 19th century.<ref>''Architecture for the Shroud: Relic and Ritual in Turin'' by John Beldon Scott - University of Chicago Press, 2003, Page 376</ref> The science of [[fracture mechanics]], as it exists today, was not developed until the 1920s, when [[Alan Arnold Griffith]] studied the [[Fracture#Brittle|brittle fracture]] of glass.
Starting in the 1940s, the infamous failures of several new technologies made a more scientific method for analyzing structural failures necessary. During [[World War II]], over 200 welded-steel ships broke in half due to brittle fracture, caused by stresses created from the welding process, temperature changes, and by the [[stress concentration]]s at the square corners of the [[Bulkhead (partition)|bulkheads]]. In the 1950s, several [[De Havilland Comet]]s exploded in mid-flight due to stress concentrations at the corners of their squared windows, which caused cracks to form and the pressurized cabins to explode. [[Boiler explosion]]s, caused by failures in pressurized boiler tanks, were another common problem during this era, and caused severe damage. The growing sizes of bridges and buildings led to even greater catastrophes and loss of life. This need to build constructions with structural integrity led to great advances in the fields of material sciences and fracture mechanics.<ref name="ReferenceA">''Assuring structural integrity in army systems'' By National Research Council (U.S.). National Materials Advisory Board, National Research Council (U.S.). Commission on Engineering and Technical Systems, National Research Council (U.S.). Committee on Assurance of Structural Integrity – 1985 Page 1—19</ref><ref name="ReferenceB">''Structural Integrity Monitoring'' By R.A. Collacott – Chapman and Hall 1985 Page 1—5</ref>
==Types of failure==
[[File:TankerSchenectady.jpg|thumb|The
Structural failure can occur from many types of problems, most of which are unique to different industries and structural types. However, most can be traced to one of five main causes.
* The first is that the structure is not strong and tough enough to support the load, due to either its size, shape, or choice of material. If the structure or component is not strong enough, catastrophic failure can occur when the structure is stressed beyond its critical stress level.
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====Dee bridge====
{{Main|Dee Bridge disaster}}
[[File:Dee bridge disaster.jpg|thumb|The Dee
The Dee Bridge in [[Chester]], England, was designed by [[Robert Stephenson]], using [[Girder|girders]] of [[cast iron]]
====First Tay
{{Main|Tay Bridge disaster}}
The Dee bridge disaster was followed by a number of [[cast iron]] bridge collapses, including the collapse of the first [[Tay
====First Tacoma Narrows Bridge====
{{Main|Tacoma Narrows Bridge (1940)}}
The 1940 collapse of the original Tacoma Narrows Bridge in [[Washington (state)|Washington]], United States, is sometimes characterized in physics textbooks as a classic example of resonance, although this description is misleading. The catastrophic vibrations that destroyed the bridge were not due to simple mechanical resonance, but to a more complicated oscillation between the bridge and winds passing through it, known as [[aeroelastic flutter]]. [[Robert H. Scanlan]], a leading contributor to the understanding of bridge aerodynamics, wrote an article about this misunderstanding.<ref>K. Billah and R. Scanlan (1991), ''Resonance, Tacoma Narrows Bridge Failure, and Undergraduate Physics Textbooks'', [[American Journal of Physics]], 59(2), 118—124 [http://www.ketchum.org/billah/Billah-Scanlan.pdf (PDF)]</ref> This collapse, and the research that followed, led to an increased understanding of wind/structure interactions. Several bridges were altered following the collapse to prevent a similar event occurring again. The only fatality was a dog.<ref name=Tacoma/>
====I-35W Bridge====
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====Thane building collapse====
{{Main|2013 Thane building collapse}}
On 4 April 2013, a building collapsed on tribal land in [[Mumbra]], a suburb of [[Thane]] in [[Maharashtra]], India.<ref name="TOI Two top engineers">{{cite web | url=http://articles.timesofindia.indiatimes.com/2013-04-10/thane/38433236_1_crime-branch-forest-department-jawahar-mokhada | title=Two top Thane municipal corporation engineers held for killer cave-in | work=The Times of India | date=10 April 2013 | access-date=10 April 2013 | archive-date=2 May 2013 | archive-url=https://web.archive.org/web/20130502035847/http://articles.timesofindia.indiatimes.com/2013-04-10/thane/38433236_1_crime-branch-forest-department-jawahar-mokhada | url-status=dead }}</ref><ref name="IBN Is Municipality as much to blame.">[http://ibnlive.in.com/news/is-municipality-as-much-to-blame-as-builders-for-thane-collapse/383421-3-237.html "Is Municipality as much to blame as builders for Thane building collapse?"] {{Webarchive|url=https://web.archive.org/web/20130407122012/http://ibnlive.in.com/news/is-municipality-as-much-to-blame-as-builders-for-thane-collapse/383421-3-237.html |date=7 April 2013 }} ''IBN''. 4 April 2013. Retrieved 5 April 2013.</ref> It has been called the worst [[building collapse]] in the area;<ref name="TOI Thane building collapse toll">{{cite news |author=Yeshwantrao |first=Nitin |date=6 April 2013 |title=Thane building collapse toll rises to 72, rescue ops end |url=https://timesofindia.indiatimes.com/city/thane/Thane-building-collapse-toll-rises-to-72-rescue-ops-end/articleshow/19414087.cms |
The building was under construction and did not have an [[Certificate of occupancy|occupancy certificate]] for its 100 to 150 low- to middle-income residents<ref name=BBC/><nowiki>;</nowiki> its only occupants were the site construction workers and their families. The building was reported to have been [[Illegal housing in India|illegally constructed]] because standard practices were not followed for safe, lawful construction, land acquisition and resident occupancy.
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====Savar building collapse====
{{Main|Rana Plaza collapse}}
On 24 April 2013,
It is considered to be the deadliest garment-factory accident in history, as well as the deadliest accidental structural failure in modern human history.<ref name="BBC">{{cite news|title=Bangladesh building collapse death toll passes 500|url=https://www.bbc.co.uk/news/world-asia-22394094|access-date=3 May 2013|publisher=BBC News|date=3 May 2013}}</ref><ref name="huffpost">{{cite news|title=Bangladesh Building Collapse Death Toll Tops 500; Engineer Whistleblower Arrested|url=http://www.huffingtonpost.com/2013/05/02/bangladesh-death-toll-tops-500_n_3199568.html|access-date=3 May 2013|work=HuffPost|date=3 May 2013}}</ref>
The building contained clothing factories, a bank, apartments, and several other shops. The shops and the bank on the lower floors immediately closed after cracks were discovered in the building.<ref name=bbc>{{cite news | url = https://www.bbc.co.uk/news/world-asia-22275597 | title = Bangladesh Dhaka building collapse leaves 80 dead| publisher= BBC News | date = 24 April 2013}}</ref><ref name=bd>{{cite web| url = http://bdnews24.com/bangladesh/2013/04/24/rana-plaza-collapse-32-dead| publisher = bdnews24.com| title = 80 dead, 800 hurt in Savar high-rise collapse| date = 24 April 2013| access-date = 24 April 2013| archive-date = 27 April 2013| archive-url = https://web.archive.org/web/20130427180411/http://bdnews24.com/bangladesh/2013/04/24/rana-plaza-collapse-32-dead| url-status = dead}}</ref><ref name=cnn>{{cite web | url =
====Sampoong Department Store collapse====
{{Main|Sampoong Department Store collapse}}
On 29 June 1995, the five-story [[Sampoong Department Store]] in the [[Seocho District]] of [[Seoul]],
In April 1995, cracks began to appear in the ceiling of the fifth floor of the store's south wing due to the presence of an air-conditioning unit on the weakened roof of the poorly built structure. On the morning of 29 June, as the number of cracks in the ceiling increased dramatically, store managers closed the top floor and shut off the air conditioning, but failed to shut the building down or issue formal evacuation orders as the executives themselves left the premises as a precaution.
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====Oklahoma City bombing====
{{Main|Oklahoma City bombing}}
On 19 April 1995, the nine-story concrete framed [[Alfred P. Murrah Federal Building]] in [[Oklahoma City]], United States, was struck by a [[Car bomb|truck bomb]] causing partial collapse, resulting in the deaths of 168 people. The bomb, though large, caused a significantly disproportionate collapse of the structure. The bomb blew all the glass off the front of the building and completely shattered a ground floor [[reinforced concrete column]] (see [[brisance]]). At second story level a wider column spacing existed, and loads from upper story columns were transferred into fewer columns below by girders at second floor level. The removal of one of the lower story columns caused neighbouring columns to fail due to the extra load, eventually leading to the complete collapse of the central portion of the building. The bombing was one of the first to highlight the extreme forces that blast loading from terrorism can exert on buildings, and led to increased consideration of terrorism in structural design of buildings.<ref name="Virdi2000">{{cite book|title=Abnormal Loading on Structures: Experimental and Numerical Modelling|author=Virdi, K.S.|year=2000|publisher=Taylor & Francis|isbn=0-419-25960-0|pages=108}}</ref>
====Versailles wedding hall====
{{Main|Versailles wedding hall disaster}}
The Versailles wedding hall ({{langx|he|אולמי ורסאי}}), located in the [[Talpiot]]
====World Trade Center Towers 1, 2, and 7====
{{Main|Collapse of the World Trade Center}}
In the [[September 11 attacks]], two commercial airliners were deliberately crashed into the Twin Towers of the [[World Trade Center (1973–2001)|World Trade Center]] in New York City. The impact, explosion and resulting fires caused both towers to collapse within less than two hours. The impacts severed exterior columns and damaged core columns, redistributing the loads that these columns had carried. This redistribution of loads was greatly influenced by the hat trusses at the top of each building.<ref name="NIST">{{cite web | title = NIST's Responsibilities Under the National Construction Safety Team Act | url = https://www.nist.gov/public_affairs/factsheet/constructionact.htm | access-date = 23 April 2008 | archive-date = 16 June 2012 | archive-url = https://web.archive.org/web/20120616104551/http://www.nist.gov/public_affairs/factsheet/constructionact.htm | url-status = dead }}</ref> The impacts dislodged some of the fireproofing from the steel, increasing its exposure to the heat of the fires. Temperatures became high enough to weaken the core columns to the point of [[Creep (deformation)|creep]] and [[Plastic deformation#Deformation theory|plastic deformation]] under the weight of higher floors. The heat of the fires also weakened the perimeter columns and floors, causing the floors to sag and exerting an inward force on exterior walls of the building.
====Champlain Towers====
{{main|Surfside condominium collapse}}
On 24 June 2021, Champlain Towers South, a 12-story condominium building in [[Surfside, Florida]], United States, partially collapsed, causing dozens of injuries and 98 deaths.<ref>{{cite web|title=97 victims in Surfside condo collapse have been identified. Officials believe there is one more unidentified victim|date=21 July 2021 |url=https://edition.cnn.com/2021/07/21/us/miami-dade-building-collapse-wednesday/index.html|publisher=CNN|access-date=22 July 2021|archive-date=21 July 2021|archive-url=https://web.archive.org/web/20210721225318/https://edition.cnn.com/2021/07/21/us/miami-dade-building-collapse-wednesday/index.html|url-status=live}}</ref> The collapse was captured on video.<ref>{{cite web| url = https://www.miamiherald.com/news/local/community/miami-dade/miami-beach/article252324218.html| url-status = dead| archive-url = https://web.archive.org/web/20210624085345/https://www.miamiherald.com/news/local/community/miami-dade/miami-beach/article252324218.html| archive-date = 2021-06-24| title = Building collapses on Collins Avenue in Surfside {{!}} Miami Herald| website =[[Miami Herald]]}}</ref> One person was rescued from the rubble,<ref>{{Cite web|url=https://miami.cbslocal.com/2021/06/24/residents-rescued-surfside-condo-building-partially-collapsed/|archive-url=https://web.archive.org/web/20210624104413/https://miami.cbslocal.com/2021/06/24/residents-rescued-surfside-condo-building-partially-collapsed/|url-status=dead|archive-date=2021-06-24|title=Residents Rescued After Surfside Condo Building Partially Collapsed}}</ref> and about 35 people were rescued on 24 June from the uncollapsed portion of the building. Long-term degradation of reinforced concrete-support structures in the underground parking garage, due to water penetration and corrosion of the reinforcing steel, has been considered as a factor in—or the cause of—the collapse. The issues had been reported in 2018 and noted as "much worse" in April 2021. A US$15 million program of remedial works had been approved at the time of the collapse.
====First Congregational Church, New London, Connecticut====
{{Main|First Church of Christ (New London, Connecticut)}}
On 24 January
===Aircraft===
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{{Main|Warsaw radio mast}}
[[File:Обломки рухнувшей Варшавской радиомачты.jpg|right|thumbnail|The Warsaw radio mast after collapse]]
On 8 August 1991 at 16:00 UTC the Warsaw radio mast near [[Gąbin]], Poland, the tallest man-made object ever built before the erection of [[Burj Khalifa]], collapsed as a consequence of an error in exchanging the guy-wires on the highest stock. The mast first bent and then snapped at roughly half its height. It destroyed at its collapse a small mobile crane of Mostostal Zabrze. As all workers had left the mast before the exchange procedures, there were no fatalities, in contrast to the similar collapse of the [[WLBT Tower]] in 1997.
====Hyatt Regency walkway====
{{Main|Hyatt Regency walkway collapse}}
[[File:HRWalkway.svg|right|thumbnail|Design change on the Hyatt Regency walkways]]
==See also==
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