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Breakage of non-structural elements
Introduction
In engineering, we speak of a structural failure when a situation occurs that exhausts the resistant capacity of a structure (understood as a set of elements designed to support certain loads, a concept that can mainly include buildings and civil engineering works, but also all types of vehicles, machines or any kind of object whose use involves resisting certain forces), causing its partial or total destruction, or having to be put out of service.
For its part, structural integrity is the ability of an element, whether a structural component or a structure consisting of many components, to hold together when subjected to loads (including its own weight), without breaking or excessively deforming. It ensures that the construction will fulfill the function for which it was designed as long as it is used reasonably during the entire time established for its useful life. Providing structural integrity to a manufactured object or a construction makes it possible to avoid catastrophic failures, which can result in injuries, severe damage, deaths and/or monetary losses.
In line with the previous definition, a structural failure is the loss of the structural integrity (or the ability to support loads) of a structural component or the structure itself. It begins when a material is stressed beyond its design strength, causing failure or excessive deformation.
In a well-designed system, a localized failure should not cause an immediate or progressive collapse of the entire structure. The limit states used in structural design allow evaluating the resistance of a structure in the event that one or some of the elements that compose it fail.
The study of structural integrity and its failures includes the analysis of past cases to prevent failures in future designs.
Structural integrity is the ability of a structure to withstand its intended load without failure due to breakage, deformation, or fatigue. It is a concept often used in engineering to produce items that will serve their designed purposes and remain functional for their desired lifespan.
To construct an item with structural integrity, an engineer must first consider the mechanical properties of the materials used, taking into account their toughness, strength, weight, hardness and elasticity, and then determine the size and shape necessary for the material to withstand the expected loads at least during its expected useful life. Since the elements of a structure must not break or bend excessively, they must retain their rigidity and possess a certain hardness. A very rigid material may resist bending, but unless it is sufficiently resistant to axial forces, its section 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 strength prevents breakage.
Breakage of non-structural elements
Introduction
In engineering, we speak of a structural failure when a situation occurs that exhausts the resistant capacity of a structure (understood as a set of elements designed to support certain loads, a concept that can mainly include buildings and civil engineering works, but also all types of vehicles, machines or any kind of object whose use involves resisting certain forces), causing its partial or total destruction, or having to be put out of service.
For its part, structural integrity is the ability of an element, whether a structural component or a structure consisting of many components, to hold together when subjected to loads (including its own weight), without breaking or excessively deforming. It ensures that the construction will fulfill the function for which it was designed as long as it is used reasonably during the entire time established for its useful life. Providing structural integrity to a manufactured object or a construction makes it possible to avoid catastrophic failures, which can result in injuries, severe damage, deaths and/or monetary losses.
In line with the previous definition, a structural failure is the loss of the structural integrity (or the ability to support loads) of a structural component or the structure itself. It begins when a material is stressed beyond its design strength, causing failure or excessive deformation.
In a well-designed system, a localized failure should not cause an immediate or progressive collapse of the entire structure. The limit states used in structural design allow evaluating the resistance of a structure in the event that one or some of the elements that compose it fail.
The study of structural integrity and its failures includes the analysis of past cases to prevent failures in future designs.
Structural integrity is the ability of a structure to withstand its intended load without failure due to breakage, deformation, or fatigue. It is a concept often used in engineering to produce items that will serve their designed purposes and remain functional for their desired lifespan.
The integrity of each component must correspond to its individual application in any supporting structure. For example, the support supports of some types of bridges need to have a high yield to compensate for the expansion of the deck, while the screws that hold them need a high resistance to shear stress and a high breaking stress. Similarly, springs require materials with high elasticity, but most tools must be manufactured with materials with high rigidity.
In addition, the entire structure must be able to support its loads without its weakest elements failing, as this can generate greater stresses in other structural elements and lead to chain failure.[1][2].
History
The need to build resistant structures dates back to very ancient times. The houses had to be able to support their own weight, plus the weight of the inhabitants. The castles had to be fortified to resist the assaults of the invaders. The tools had to be strong and durable enough to do their job effectively. However, the science of fracture mechanics as we know it today was not developed until the 1920s, when Alan Arnold Griffith studied the brittle fracture of glass.
Beginning in the 1940s, disastrous failures caused by some new technologies made it necessary to employ a more scientific method to analyze structural failures. During World War II, more than 200 welded steel ships broke in half due to brittle fracture problems, caused by the stresses created by the welding process, temperature changes, and by stress concentration at the right-angle corners of bulkheads. In the 1950s, several De Havilland DH.106 Comet aircraft exploded in mid-flight due to stress concentrations in the corners of their square windows, causing cracks to form and the pressurized cabins to explode. Boiler explosions", caused by failures in their pressurized chambers, were another common problem during this era and sometimes caused considerable damage. The increasing size of bridges and buildings led to even greater catastrophes and loss of life. This need to ensure the structural integrity of buildings led to great advances in the fields of materials science and fracture mechanics.[3][4].
Types of failures
Structural failures can be caused by various kinds of problems, most of which are unique to different industries and types of structures. However, most can be attributed to one of these five main causes:.
Notable flaws
Bridges
The River Dee Bridge was designed by Robert Stephenson, using cast iron girders reinforced with wrought iron struts. On May 24, 1847, it collapsed as a train passed over it, killing five people. Its collapse was the subject of one of the first formal investigations into structural failure. This investigation concluded that the design of the structure was fundamentally flawed, as the wrought iron did not reinforce the casting elements as expected and the casting had failed due to repeated bending.[6].
The Dee Bridge disaster was followed by a series of cast iron bridge collapses, including the collapse of the first Tay Railway Bridge on 28 December 1879. Like the Dee Bridge, the Tay Viaduct collapsed when a train passed over it, killing 75 people. The bridge failed because it was built of poorly produced cast iron and because the engineer behind the project, Thomas Bouch, did not consider the wind load on the structure. Its collapse led to cast iron being replaced by steel construction and a complete redesign in 1890 of the Forth Bridge, making it the world's first all-steel bridge.[7].
The 1940 collapse of the original Tacoma Narrows Bridge 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 the winds passing through it, known as aeroelasticity. Robert H. Scanlan"), a major contributor to the understanding of bridge aerodynamics, wrote an article about this misunderstanding.[8] The collapse of the suspension bridge and the research that followed led to a greater understanding of wind/structure interactions. Several bridges were modified after the Tacoma collapse to prevent such a thing from happening again. The only fatality was a dog named Tubby.[7].
The I-35W Bridge (officially known simply as Bridge 9340) was an eight-lane steel truss arch structure of Interstate 35W "Interstate 35W (Minnesota)") over the Mississippi River in Minneapolis, United States. The bridge was completed in 1967 and was maintained by the Minnesota Department of Transportation. It was the fifth busiest crossing in Minnesota,[9][10] carrying 140,000 vehicles a day.[11] The bridge suffered a catastrophic failure in the middle of rush hour, during the night of August 1, 2007, collapsing into the river. Thirteen people were killed and 145 injured. After the collapse, the Federal Highway Administration recommended states inspect all 700 similarly constructed U.S. bridges[12] after a possible design flaw was discovered in the bridge, related to the design of the haunches (oversized steel plates) that were used to connect girders of the truss structure.[13][14] Officials expressed concern about many other bridges in the United States. that shared the same design and raised questions about why the problem had not been discovered in more than 40 years of inspections.[14].
Buildings
On April 4, 2013, a building collapsed on communal land in Mumbra, a suburb of the city of Thane in Maharashtra, India. It has been described as one of the worst building collapses in India: 74 people died, including 18 children, 23 women and 33 men, although He was able to rescue 100 survivors.[20][21][22]
The building was under construction, and did not yet have a certificate of occupancy to accommodate its planned 100 to 150 low- to moderate-income residents.[23] Its only occupants at the time of the collapse were the building's own construction workers and their families. The building was reported to have been constructed illegally because standard practices for safe and legal construction, land acquisition, and resident occupancy were not followed.
By April 11, a total of 15 suspects were arrested, including builders, engineers, municipal officials and other responsible parties. Government records indicate that instructions were given to control the number of illegal buildings in the area: a 2005 order from the state of Maharashtra to use remote sensing and a 2010 order from the Bombay High Court. Complaints were also filed against state and municipal officials.
On April 9, the Thane Municipal Corporation launched a drive to demolish illegal buildings in the area, putting a spotlight on "potentially dangerous" buildings, and set up a call center to accept and track resolutions of complaints about illegal buildings. Meanwhile, the forest department has promised to address the issue of forest land encroachment in Thane district.
On April 24, 2013, the Rana Plaza, an eight-story commercial building, collapsed in Savar, a subdistrict in the Greater Dhaka Area, the capital of Bangladesh. The search for the dead ended on May 13, leaving 1,134 dead.[24] Approximately 2,515 injured people were rescued alive from the building.[25][26].
It is considered the deadliest clothing factory accident in history, as well as the most serious structural failure in modern history.[23][27].
The building contained clothing factories, a bank, apartments and several other stores. Shops and the bank on the lower floors closed immediately after cracks were discovered in the building.[28][29][30] Warnings to avoid using the building were ignored after cracks appeared the previous day. The garment workers were ordered to return the next day, and the building collapsed during the morning rush hour.[31].
On June 29, 1995, the Sampoong department store, a five-story building located in Seocho-gu, Seoul, South Korea, collapsed, killing 502 people and trapping another 1,445.
In April 1995, cracks began to appear in the ceiling of the fifth floor of the south wing of the building, due to the presence of an air conditioning unit in the weakened roof of the poorly constructed structure. On the morning of June 29, as the number of cracks in the ceiling increased dramatically, store managers closed the upper floor and turned off the air conditioning, but did not lock the building or issue formal evacuation orders when the executives themselves left the premises as a precaution.
Aircraft
Repeated structural failures of the same type of aircraft occurred in 1954, when two De Havilland DH.106 Comet jets crashed due to decompression caused by fuselage failure due to material fatigue, and in 1963–64, when the stabilizing surfaces of four Boeing B-52 bombers broke in mid-air.
Others
On August 8, 1991 at 16:00 UTC, the Warsaw radio antenna, the tallest structure ever erected before the construction of the Burj Khalifa tower, collapsed as a result of an error in changing the guy wires at the highest level. The mast first bent and then snapped about half its height. A small mobile crane in Mostostal Zabrze was destroyed. As all workers left the mast before carrying out the maneuver to reposition the guy cables, there were no fatalities, in contrast to the similar collapse of the WLBT Tower in 1997.
On July 17, 1981, two walkways suspended above the lobby of the Hyatt Hotel in Kansas City, Missouri collapsed, killing 114 people and injuring more than 200 during a tea dance. The collapse was due to a last-minute design change, which altered the method by which the rods supporting the walkways were connected to them. The change inadvertently doubled the stresses being supported at the connection points. The ruling highlighted the need for good communication between design engineers and contractors, as well as rigorous controls on projects and, especially, design changes proposed by contractors. Failure is a standard case study in engineering courses around the world, and is used to teach the importance of ethical behavior in engineering.[41][42].
On February 21, 2025, at approximately 20:40 (GTM-5 time), the Real Plaza Trujillo shopping center in Trujillo "Trujillo (Perú)") (Peru), suffered a structural failure when part of its roof collapsed. The incident left at least eight dead, including children, and 84 injured. The collapse mainly affected the food court and the children's play area of the establishment.[43][44][45] This is one of the most important deadly events that occurred in a leisure venue managed by a private company and the treatment of the victims has been compared to that of the fire at the Utopia nightclub in Jockey Plaza.[46].
On May 22, 2024, at 20:08 CST (GTM−6), a stage collapsed during a campaign rally for Nuevo León mayoral candidate Lorenia Canavati") and presidential candidate Jorge Máynez by the Citizen Movement political party in San Pedro Garza García, in the northeastern Mexican state of Nuevo León, the incident left at least 10 dead and 213 injured.[47][48] It is known that one of the main causes of this collapse, apart from the poor infrastructure of the place, were the weather conditions with wind gusts of 50 to 70 km/h.[49].
References
[20] ↑ También se le ha llamado el peor desastre por derrumbe de edificios en los últimos 10 años en el estado de Maharashtra.[18] y el peor del país en 20 años.[19].
To construct an item with structural integrity, an engineer must first consider the mechanical properties of the materials used, taking into account their toughness, strength, weight, hardness and elasticity, and then determine the size and shape necessary for the material to withstand the expected loads at least during its expected useful life. Since the elements of a structure must not break or bend excessively, they must retain their rigidity and possess a certain hardness. A very rigid material may resist bending, but unless it is sufficiently resistant to axial forces, its section 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 strength prevents breakage.
The integrity of each component must correspond to its individual application in any supporting structure. For example, the support supports of some types of bridges need to have a high yield to compensate for the expansion of the deck, while the screws that hold them need a high resistance to shear stress and a high breaking stress. Similarly, springs require materials with high elasticity, but most tools must be manufactured with materials with high rigidity.
In addition, the entire structure must be able to support its loads without its weakest elements failing, as this can generate greater stresses in other structural elements and lead to chain failure.[1][2].
History
The need to build resistant structures dates back to very ancient times. The houses had to be able to support their own weight, plus the weight of the inhabitants. The castles had to be fortified to resist the assaults of the invaders. The tools had to be strong and durable enough to do their job effectively. However, the science of fracture mechanics as we know it today was not developed until the 1920s, when Alan Arnold Griffith studied the brittle fracture of glass.
Beginning in the 1940s, disastrous failures caused by some new technologies made it necessary to employ a more scientific method to analyze structural failures. During World War II, more than 200 welded steel ships broke in half due to brittle fracture problems, caused by the stresses created by the welding process, temperature changes, and by stress concentration at the right-angle corners of bulkheads. In the 1950s, several De Havilland DH.106 Comet aircraft exploded in mid-flight due to stress concentrations in the corners of their square windows, causing cracks to form and the pressurized cabins to explode. Boiler explosions", caused by failures in their pressurized chambers, were another common problem during this era and sometimes caused considerable damage. The increasing size of bridges and buildings led to even greater catastrophes and loss of life. This need to ensure the structural integrity of buildings led to great advances in the fields of materials science and fracture mechanics.[3][4].
Types of failures
Structural failures can be caused by various kinds of problems, most of which are unique to different industries and types of structures. However, most can be attributed to one of these five main causes:.
Notable flaws
Bridges
The River Dee Bridge was designed by Robert Stephenson, using cast iron girders reinforced with wrought iron struts. On May 24, 1847, it collapsed as a train passed over it, killing five people. Its collapse was the subject of one of the first formal investigations into structural failure. This investigation concluded that the design of the structure was fundamentally flawed, as the wrought iron did not reinforce the casting elements as expected and the casting had failed due to repeated bending.[6].
The Dee Bridge disaster was followed by a series of cast iron bridge collapses, including the collapse of the first Tay Railway Bridge on 28 December 1879. Like the Dee Bridge, the Tay Viaduct collapsed when a train passed over it, killing 75 people. The bridge failed because it was built of poorly produced cast iron and because the engineer behind the project, Thomas Bouch, did not consider the wind load on the structure. Its collapse led to cast iron being replaced by steel construction and a complete redesign in 1890 of the Forth Bridge, making it the world's first all-steel bridge.[7].
The 1940 collapse of the original Tacoma Narrows Bridge 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 the winds passing through it, known as aeroelasticity. Robert H. Scanlan"), a major contributor to the understanding of bridge aerodynamics, wrote an article about this misunderstanding.[8] The collapse of the suspension bridge and the research that followed led to a greater understanding of wind/structure interactions. Several bridges were modified after the Tacoma collapse to prevent such a thing from happening again. The only fatality was a dog named Tubby.[7].
The I-35W Bridge (officially known simply as Bridge 9340) was an eight-lane steel truss arch structure of Interstate 35W "Interstate 35W (Minnesota)") over the Mississippi River in Minneapolis, United States. The bridge was completed in 1967 and was maintained by the Minnesota Department of Transportation. It was the fifth busiest crossing in Minnesota,[9][10] carrying 140,000 vehicles a day.[11] The bridge suffered a catastrophic failure in the middle of rush hour, during the night of August 1, 2007, collapsing into the river. Thirteen people were killed and 145 injured. After the collapse, the Federal Highway Administration recommended states inspect all 700 similarly constructed U.S. bridges[12] after a possible design flaw was discovered in the bridge, related to the design of the haunches (oversized steel plates) that were used to connect girders of the truss structure.[13][14] Officials expressed concern about many other bridges in the United States. that shared the same design and raised questions about why the problem had not been discovered in more than 40 years of inspections.[14].
Buildings
On April 4, 2013, a building collapsed on communal land in Mumbra, a suburb of the city of Thane in Maharashtra, India. It has been described as one of the worst building collapses in India: 74 people died, including 18 children, 23 women and 33 men, although He was able to rescue 100 survivors.[20][21][22]
The building was under construction, and did not yet have a certificate of occupancy to accommodate its planned 100 to 150 low- to moderate-income residents.[23] Its only occupants at the time of the collapse were the building's own construction workers and their families. The building was reported to have been constructed illegally because standard practices for safe and legal construction, land acquisition, and resident occupancy were not followed.
By April 11, a total of 15 suspects were arrested, including builders, engineers, municipal officials and other responsible parties. Government records indicate that instructions were given to control the number of illegal buildings in the area: a 2005 order from the state of Maharashtra to use remote sensing and a 2010 order from the Bombay High Court. Complaints were also filed against state and municipal officials.
On April 9, the Thane Municipal Corporation launched a drive to demolish illegal buildings in the area, putting a spotlight on "potentially dangerous" buildings, and set up a call center to accept and track resolutions of complaints about illegal buildings. Meanwhile, the forest department has promised to address the issue of forest land encroachment in Thane district.
On April 24, 2013, the Rana Plaza, an eight-story commercial building, collapsed in Savar, a subdistrict in the Greater Dhaka Area, the capital of Bangladesh. The search for the dead ended on May 13, leaving 1,134 dead.[24] Approximately 2,515 injured people were rescued alive from the building.[25][26].
It is considered the deadliest clothing factory accident in history, as well as the most serious structural failure in modern history.[23][27].
The building contained clothing factories, a bank, apartments and several other stores. Shops and the bank on the lower floors closed immediately after cracks were discovered in the building.[28][29][30] Warnings to avoid using the building were ignored after cracks appeared the previous day. The garment workers were ordered to return the next day, and the building collapsed during the morning rush hour.[31].
On June 29, 1995, the Sampoong department store, a five-story building located in Seocho-gu, Seoul, South Korea, collapsed, killing 502 people and trapping another 1,445.
In April 1995, cracks began to appear in the ceiling of the fifth floor of the south wing of the building, due to the presence of an air conditioning unit in the weakened roof of the poorly constructed structure. On the morning of June 29, as the number of cracks in the ceiling increased dramatically, store managers closed the upper floor and turned off the air conditioning, but did not lock the building or issue formal evacuation orders when the executives themselves left the premises as a precaution.
Aircraft
Repeated structural failures of the same type of aircraft occurred in 1954, when two De Havilland DH.106 Comet jets crashed due to decompression caused by fuselage failure due to material fatigue, and in 1963–64, when the stabilizing surfaces of four Boeing B-52 bombers broke in mid-air.
Others
On August 8, 1991 at 16:00 UTC, the Warsaw radio antenna, the tallest structure ever erected before the construction of the Burj Khalifa tower, collapsed as a result of an error in changing the guy wires at the highest level. The mast first bent and then snapped about half its height. A small mobile crane in Mostostal Zabrze was destroyed. As all workers left the mast before carrying out the maneuver to reposition the guy cables, there were no fatalities, in contrast to the similar collapse of the WLBT Tower in 1997.
On July 17, 1981, two walkways suspended above the lobby of the Hyatt Hotel in Kansas City, Missouri collapsed, killing 114 people and injuring more than 200 during a tea dance. The collapse was due to a last-minute design change, which altered the method by which the rods supporting the walkways were connected to them. The change inadvertently doubled the stresses being supported at the connection points. The ruling highlighted the need for good communication between design engineers and contractors, as well as rigorous controls on projects and, especially, design changes proposed by contractors. Failure is a standard case study in engineering courses around the world, and is used to teach the importance of ethical behavior in engineering.[41][42].
On February 21, 2025, at approximately 20:40 (GTM-5 time), the Real Plaza Trujillo shopping center in Trujillo "Trujillo (Perú)") (Peru), suffered a structural failure when part of its roof collapsed. The incident left at least eight dead, including children, and 84 injured. The collapse mainly affected the food court and the children's play area of the establishment.[43][44][45] This is one of the most important deadly events that occurred in a leisure venue managed by a private company and the treatment of the victims has been compared to that of the fire at the Utopia nightclub in Jockey Plaza.[46].
On May 22, 2024, at 20:08 CST (GTM−6), a stage collapsed during a campaign rally for Nuevo León mayoral candidate Lorenia Canavati") and presidential candidate Jorge Máynez by the Citizen Movement political party in San Pedro Garza García, in the northeastern Mexican state of Nuevo León, the incident left at least 10 dead and 213 injured.[47][48] It is known that one of the main causes of this collapse, apart from the poor infrastructure of the place, were the weather conditions with wind gusts of 50 to 70 km/h.[49].
References
[20] ↑ También se le ha llamado el peor desastre por derrumbe de edificios en los últimos 10 años en el estado de Maharashtra.[18] y el peor del país en 20 años.[19].
Five hours before the collapse, the first of several loud impacts was heard coming from the upper floors, as vibration from the air conditioning caused cracks in the slabs to widen even further. Amid customer reports of vibrations in the building, the air conditioning was turned off, but cracks in the floors had already grown to 10cm wide. At approximately 5:00 p.m. m. local time, the ceiling of the fifth floor began to cave in, and at 5:57 p.m. m., the roof gave way and the air conditioning unit crashed onto the already overloaded floor.
On May 16, 1968, the 22-story Ronan Point residential tower (located in the Greater London neighborhood of Newham) collapsed when a relatively small gas explosion on the 18th floor caused a structural wall panel to be ejected from the building. The tower was constructed of precast concrete and the failure of a single panel caused an entire corner of the building to collapse. The panel could have been thrown off because there was not enough through-through reinforcing steel at the joint between the panels. This also meant that the loads supported by the panel could not be redistributed to other adjacent panels, due to the weak connection which prevented the transmission of forces. As a result of the collapse, building regulations were revised to prevent such collapses, and the details of precast concrete elements to improve their resistance to overpressures were greatly advanced. Many similar buildings were modified or demolished as a result of this accident.[32].
On April 19, 1995, the Alfred P. Murrah Federal Building, a nine-story reinforced concrete structure located in Oklahoma, was hit by a car bomb explosion that caused it to partially collapse, killing 168 people. The bomb, although powerful, caused disproportionate damage to the structure. The bomb blew out all the glass in the front of the building and completely shattered a reinforced concrete pillar on the ground floor. At the second floor level the building had a wider column spacing, the loads of which were transferred to the set of pillars on the lower level, where the disappearance of one of the pillars caused the neighboring pillars to fail due to the additional load, which ultimately caused the complete collapse of the central part of the building. It was one of the first cases to highlight that explosions caused by terrorism can cause extreme effects on buildings, which led to greater consideration of possible attacks in the structural design of buildings.[33].
The Versailles Wedding Hall (Hebrew: ), located in Talpiot, Jerusalem, is the site of the worst civil disaster in Israel's history. At 10:43 p.m. on Thursday, May 24, 2001, during the wedding of Keren and Asaf Dror, a large part of the third floor of the four-story building collapsed, killing 23 people. The couple survived.
In the attacks of September 11, 2001, two commercial airliners deliberately crashed into the Twin Towers of the World Trade Center "World Trade Center (1973-2001)") in New York City. The impact and resulting fires caused both towers to collapse in less than two hours. The impacts severed some outer columns and damaged the central columns, which had absorbed loads that the severed columns could no longer support. This redistribution of loads was greatly influenced by the existing trusses at the top of each tower.[34] The impacts detached part of the fireproof material that protected the steel structure, increasing its exposure to the effect of fire. Temperatures became high enough to weaken the central columns to the point of reaching the state of creep and plastic deformation "Deformation (engineering)") under the weight of the upper floors. The heat from the fires also weakened the perimeter columns and floors, causing the floors to sag and exert an inward force on the exterior walls of the building. WTC Building 7 also collapsed that same day; The 47-story skyscraper collapsed in seconds due to the combination of a large fire inside with the extensive structural damage caused by the collapse of the North Tower.[35][36].
On June 24, 2021, the Champlain Towers South, a 12-story condo building in Surfside, Florida, partially collapsed, causing dozens of injuries and 98 deaths.[37] The collapse was captured on video.[38] One person was rescued from the rubble,[39] and about 35 people were rescued on June 24 from the non-collapsed portion of the building. Long-term degradation of the reinforced concrete supporting structures in the underground parking lot due to water penetration and corrosion of the reinforcing steel is considered a factor or the main cause of the collapse. The problems identified had already been reported in 2018 and were rated as “much worse” in April 2021. A $15 million repair works program had been approved at the time of the collapse. On July 11, 2021, the death of 90 people and the disappearance of another 31 had been confirmed.
Five hours before the collapse, the first of several loud impacts was heard coming from the upper floors, as vibration from the air conditioning caused cracks in the slabs to widen even further. Amid customer reports of vibrations in the building, the air conditioning was turned off, but cracks in the floors had already grown to 10cm wide. At approximately 5:00 p.m. m. local time, the ceiling of the fifth floor began to cave in, and at 5:57 p.m. m., the roof gave way and the air conditioning unit crashed onto the already overloaded floor.
On May 16, 1968, the 22-story Ronan Point residential tower (located in the Greater London neighborhood of Newham) collapsed when a relatively small gas explosion on the 18th floor caused a structural wall panel to be ejected from the building. The tower was constructed of precast concrete and the failure of a single panel caused an entire corner of the building to collapse. The panel could have been thrown off because there was not enough through-through reinforcing steel at the joint between the panels. This also meant that the loads supported by the panel could not be redistributed to other adjacent panels, due to the weak connection which prevented the transmission of forces. As a result of the collapse, building regulations were revised to prevent such collapses, and the details of precast concrete elements to improve their resistance to overpressures were greatly advanced. Many similar buildings were modified or demolished as a result of this accident.[32].
On April 19, 1995, the Alfred P. Murrah Federal Building, a nine-story reinforced concrete structure located in Oklahoma, was hit by a car bomb explosion that caused it to partially collapse, killing 168 people. The bomb, although powerful, caused disproportionate damage to the structure. The bomb blew out all the glass in the front of the building and completely shattered a reinforced concrete pillar on the ground floor. At the second floor level the building had a wider column spacing, the loads of which were transferred to the set of pillars on the lower level, where the disappearance of one of the pillars caused the neighboring pillars to fail due to the additional load, which ultimately caused the complete collapse of the central part of the building. It was one of the first cases to highlight that explosions caused by terrorism can cause extreme effects on buildings, which led to greater consideration of possible attacks in the structural design of buildings.[33].
The Versailles Wedding Hall (Hebrew: ), located in Talpiot, Jerusalem, is the site of the worst civil disaster in Israel's history. At 10:43 p.m. on Thursday, May 24, 2001, during the wedding of Keren and Asaf Dror, a large part of the third floor of the four-story building collapsed, killing 23 people. The couple survived.
In the attacks of September 11, 2001, two commercial airliners deliberately crashed into the Twin Towers of the World Trade Center "World Trade Center (1973-2001)") in New York City. The impact and resulting fires caused both towers to collapse in less than two hours. The impacts severed some outer columns and damaged the central columns, which had absorbed loads that the severed columns could no longer support. This redistribution of loads was greatly influenced by the existing trusses at the top of each tower.[34] The impacts detached part of the fireproof material that protected the steel structure, increasing its exposure to the effect of fire. Temperatures became high enough to weaken the central columns to the point of reaching the state of creep and plastic deformation "Deformation (engineering)") under the weight of the upper floors. The heat from the fires also weakened the perimeter columns and floors, causing the floors to sag and exert an inward force on the exterior walls of the building. WTC Building 7 also collapsed that same day; The 47-story skyscraper collapsed in seconds due to the combination of a large fire inside with the extensive structural damage caused by the collapse of the North Tower.[35][36].
On June 24, 2021, the Champlain Towers South, a 12-story condo building in Surfside, Florida, partially collapsed, causing dozens of injuries and 98 deaths.[37] The collapse was captured on video.[38] One person was rescued from the rubble,[39] and about 35 people were rescued on June 24 from the non-collapsed portion of the building. Long-term degradation of the reinforced concrete supporting structures in the underground parking lot due to water penetration and corrosion of the reinforcing steel is considered a factor or the main cause of the collapse. The problems identified had already been reported in 2018 and were rated as “much worse” in April 2021. A $15 million repair works program had been approved at the time of the collapse. On July 11, 2021, the death of 90 people and the disappearance of another 31 had been confirmed.