Building implosion
Encyclopedia
In the controlled demolition
industry, building implosion is the strategic placing of explosive material
and timing of its detonation so that a structure collapses on itself in a matter of seconds, minimizing the physical damage to its immediate surroundings. Despite its terminology, building implosion also includes the controlled demolition of other structures, such as bridge
s, smokestacks, tower
s, and tunnel
s.
Building implosion (which reduces to seconds a process which could take months or years to achieve by other methods) typically occurs in urban areas and often involves large landmark structures.
The actual use of the term "implosion" to refer to the destruction of a building is a misnomer
. This had been stated of the destruction of 1515 Tower
in West Palm Beach, Florida. "What happens is, you use explosive materials in critical structural connections to allow gravity to bring it down."
In contrast, building implosion techniques do not rely on the difference between internal and external pressure to collapse a structure. Instead, the technique weakens or removes critical supports so that the building can no longer withstand the force of gravity and falls under its own weight.
Numerous small explosives, strategically placed within the structure, are used to catalyze the collapse. Nitroglycerin, dynamite
, or other explosives are used to shatter reinforced concrete supports. Linear shaped charges
are used to sever steel supports. These explosives are progressively detonated on supports throughout the structure. Then, explosives on the lower floors initiate the controlled collapse.
A simple structure like a chimney can be prepared for demolition in less than a day. Larger or more complex structures can take up to six months of preparation to remove internal walls and wrap columns with fabric and fencing before firing the explosives.
As part of the demolition
industry, the history of building implosion is tied to the development of explosives
technology.
One of the earliest documented attempts at building implosion was the 1773 razing of Holy Trinity Cathedral in Waterford
, Ireland
with 150 pounds of gunpowder
, a huge amount of explosives at the time. The use of low velocity explosive produced a deafening explosion that instantly reduced the building to rubble.
The late 19th Century saw the erection of—and ultimately the need to demolish—the first skyscraper
s, which had more complicated structures allowing greater heights. This led to other considerations in the explosive demolition of buildings, such as worker and spectator safety and limiting collateral damage. Benefiting from the availability of dynamite
, a high-velocity explosive based on a stabilized form of nitroglycerine, and borrowing from techniques used in rock-blasting, such as staggered detonation of several small charges, building demolition edged toward efficient building implosion.
Following World War II
, European demolition experts faced with massive reconstruction projects in dense urban areas gathered practical knowledge and experience for bringing down large structures without harming adjacent properties.
This led to the emergence of a demolition industry that grew and matured during the latter half of the twentieth century. At the same time, the development of more efficient high-velocity explosives such as RDX
and non-electrical firing systems combined to make this a period of time in which the building implosion technique was extensively used.
Meanwhile, public interest in the spectacle of controlled building explosion also grew. The October 1994 demolition of the Sears Merchandise Center in Philadelphia, Pennsylvania
drew a cheering crowd of 50,000, as well as protesters, bands, and street vendors hawking building implosion memorabilia.
Evolution in the mastery of controlled demolition led to the world record demolition of the Seattle Kingdome on March 26, 2000.
In 1997, a building implosion in Canberra, Australia
experienced disaster. The main building did not fully disintegrate and had to be manually demolished. Far worse, the explosion was not contained on the site and large pieces of debris were projected towards spectators 500 metres away, in a location considered safe for viewing. A twelve-year old girl was killed instantly, and nine others were injured. Large fragments of masonry and metal were found 650 metres from the demolition site.
On October 24, 1998, the J.L. Hudson Department Store and Addition
became the tallest, and the largest, building ever imploded.
On December 13, 2009, an unfinished 31-story condominium tower, known as the Ocean Tower, was imploded in South Padre Island, Texas
. Construction on the new tower began in 2006, but had been sinking unevenly during construction, halted in 2008, and could not be saved. It is believed to be one of the tallest reinforced concrete structures ever imploded.
Controlled demolition
Controlled demolition refers to:* Demolition, the tearing-down of buildings and other structures* Controlled Demolition, Inc., Phoenix, Maryland firm that specializes in the use of explosives to create a controlled demolition of a structure...
industry, building implosion is the strategic placing of explosive material
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...
and timing of its detonation so that a structure collapses on itself in a matter of seconds, minimizing the physical damage to its immediate surroundings. Despite its terminology, building implosion also includes the controlled demolition of other structures, such as bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
s, smokestacks, tower
Tower
A tower is a tall structure, usually taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires....
s, and tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...
s.
Building implosion (which reduces to seconds a process which could take months or years to achieve by other methods) typically occurs in urban areas and often involves large landmark structures.
The actual use of the term "implosion" to refer to the destruction of a building is a misnomer
Misnomer
A misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derive their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...
. This had been stated of the destruction of 1515 Tower
1515 Tower
1515 Tower is a former residential high-rise in West Palm Beach, Florida. Completed in 1974, it was the second tallest building in West Palm Beach with 30 stories and rising ....
in West Palm Beach, Florida. "What happens is, you use explosive materials in critical structural connections to allow gravity to bring it down."
Terminology
The term building implosion can be misleading to laymen: the technique is not a true implosion phenomenon. A true implosion usually involves a difference between internal (lower) and external (higher) pressure, or inward and outward forces, that is so large that the structure collapses inward into itself.In contrast, building implosion techniques do not rely on the difference between internal and external pressure to collapse a structure. Instead, the technique weakens or removes critical supports so that the building can no longer withstand the force of gravity and falls under its own weight.
Numerous small explosives, strategically placed within the structure, are used to catalyze the collapse. Nitroglycerin, dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
, or other explosives are used to shatter reinforced concrete supports. Linear shaped charges
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
are used to sever steel supports. These explosives are progressively detonated on supports throughout the structure. Then, explosives on the lower floors initiate the controlled collapse.
A simple structure like a chimney can be prepared for demolition in less than a day. Larger or more complex structures can take up to six months of preparation to remove internal walls and wrap columns with fabric and fencing before firing the explosives.
Historical overview
Demolition
Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use....
industry, the history of building implosion is tied to the development of explosives
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...
technology.
One of the earliest documented attempts at building implosion was the 1773 razing of Holy Trinity Cathedral in Waterford
Waterford
Waterford is a city in the South-East Region of Ireland. It is the oldest city in the country and fifth largest by population. Waterford City Council is the local government authority for the city and its immediate hinterland...
, Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
with 150 pounds of gunpowder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
, a huge amount of explosives at the time. The use of low velocity explosive produced a deafening explosion that instantly reduced the building to rubble.
The late 19th Century saw the erection of—and ultimately the need to demolish—the first skyscraper
Skyscraper
A skyscraper is a tall, continuously habitable building of many stories, often designed for office and commercial use. There is no official definition or height above which a building may be classified as a skyscraper...
s, which had more complicated structures allowing greater heights. This led to other considerations in the explosive demolition of buildings, such as worker and spectator safety and limiting collateral damage. Benefiting from the availability of dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
, a high-velocity explosive based on a stabilized form of nitroglycerine, and borrowing from techniques used in rock-blasting, such as staggered detonation of several small charges, building demolition edged toward efficient building implosion.
Following World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, European demolition experts faced with massive reconstruction projects in dense urban areas gathered practical knowledge and experience for bringing down large structures without harming adjacent properties.
This led to the emergence of a demolition industry that grew and matured during the latter half of the twentieth century. At the same time, the development of more efficient high-velocity explosives such as RDX
RDX
RDX, an initialism for Research Department Explosive, is an explosive nitroamine widely used in military and industrial applications. It was developed as an explosive which was more powerful than TNT, and it saw wide use in WWII. RDX is also known as cyclonite, hexogen , and T4...
and non-electrical firing systems combined to make this a period of time in which the building implosion technique was extensively used.
Meanwhile, public interest in the spectacle of controlled building explosion also grew. The October 1994 demolition of the Sears Merchandise Center in Philadelphia, Pennsylvania
Philadelphia, Pennsylvania
Philadelphia is the largest city in the Commonwealth of Pennsylvania and the county seat of Philadelphia County, with which it is coterminous. The city is located in the Northeastern United States along the Delaware and Schuylkill rivers. It is the fifth-most-populous city in the United States,...
drew a cheering crowd of 50,000, as well as protesters, bands, and street vendors hawking building implosion memorabilia.
Evolution in the mastery of controlled demolition led to the world record demolition of the Seattle Kingdome on March 26, 2000.
In 1997, a building implosion in Canberra, Australia
Royal Canberra Hospital implosion
The Royal Canberra Hospital implosion was a failed building implosion with lethal consequences. The implosion occurred on 13 July 1997, when the city's superseded hospital buildings at Acton Peninsula on Lake Burley Griffin were demolished to make way for the National Museum of...
experienced disaster. The main building did not fully disintegrate and had to be manually demolished. Far worse, the explosion was not contained on the site and large pieces of debris were projected towards spectators 500 metres away, in a location considered safe for viewing. A twelve-year old girl was killed instantly, and nine others were injured. Large fragments of masonry and metal were found 650 metres from the demolition site.
On October 24, 1998, the J.L. Hudson Department Store and Addition
J.L. Hudson Department Store and Addition
The J.L. Hudson Building was a department store in Detroit, Michigan, which occupied the address of 1206 Woodward Avenue. It was constructed beginning in 1911, with additions throughout the years, before being "completed" in 1946, and named after the company's founder, Joseph Lowthian Hudson...
became the tallest, and the largest, building ever imploded.
On December 13, 2009, an unfinished 31-story condominium tower, known as the Ocean Tower, was imploded in South Padre Island, Texas
South Padre Island, Texas
South Padre Island is a town in Cameron County, Texas, United States. It is part of the Brownsville–Harlingen Metropolitan Statistical Area. It may be included as part of the Brownsville–Harlingen–Raymondville and the Matamoros–Brownsville metropolitan areas. The population was 2,816 at the...
. Construction on the new tower began in 2006, but had been sinking unevenly during construction, halted in 2008, and could not be saved. It is believed to be one of the tallest reinforced concrete structures ever imploded.
External links
- Demolition Simulation Advanced structural analysis for predicting demolitions.
- A History of Structural Demolition in America by Brent L. Blanchard
- How Building Implosions Work by Tom Harris on www.howstuffworks.comHowStuffWorksHowStuffWorks is a commercial edutainment website that was founded by Marshall Brain with the goal of giving its target audience an insight into the way in which many things work. The site uses various media in its effort to explain complex concepts, terminology and mechanisms, including...
- Building Implosions Videos
- Bank Implosion Videos and Photos Videos