1. Introduction
In general, building design usually considers environmental or external loads that a building must have the strength to resist. These loads are gravity, wind and earthquake loads. Leading a high rise building to collapse, the key failure is the failure of transferring load from the building above the failure point to the foundation. There are numbers of reasons to cause the failure of load transfer, such as poor inspection before construction and foundation failure.
In the past few years, the most representable collapse of a building should be the World Trade Center in 2001. The collapse indicates the significance of impact load. Impact load refers to the load that is brought to bear in a short period of time. This can result from the added weight caused by the collapse of internal structural elements and explosions.
2. Collapse of the World Trade Center
2.1 Background Information
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However, when multiple members fail, the shifting loads eventually overstress the adjacent members and the collapse occurs like a row of dominoes falling down.
As mentioned in the early part of the essay, the North Tower was a tube in tube steel framed structure skyscraper. After the impact load acted onto the building, the Northern facade of the North Tower was lacked supporting system from floors 94-98. The damage on the structural system on floors 94-98 caused the load above could not transmit normally through floors 94- 98 towards to the lower part of the building, than to the foundation. As a result, the failure of load transmission caused the collapse of floors above 98/F. And this is the third reason of the North Tower collapsed.
The perimeter tube design of the WTC was highly redundant. It survived the loss of several exterior columns due to aircraft impact, but the ensuing fire led to other steel
There have been suspicions surrounding how the towers collapsed into dust. Some say it was a “pancake” collapse. According to Engineers, a pancake collapse or progressive collapse is when the weight of all the floors above the collapsed zone bears down with pulverizing force on the highest intact floor and unable to absorb the energy, that floor would fail, transmitting the forces to the floor below, allowing the collapse to progress downward through the ...
On the morning of September 11/2001, 19 terrorist working for the Al Qaeda terrorist organization hijacked four commercial planes. They attempted to fly them into multiple U.S targets. One of the planes, American Airlines, flight 11, crashed into the north tower of the World Trade Center at 8:50 a.m. Another plane, United Airlines, flight 175, crashed into the south tower at 9:04 a.m. These tragedies took the lives of nearly 3000 people and affected the lives of millions.
Soon after, Flight 175 attacked the South Tower. By the end of the day, both towers had collapsed and other hijacked flights had caused damage. The amount of lives lost on September 11 was substantial; 2,749 people from eighty-three different countries died from the attacks (Facts about the attacks., n.d.). All in all, America has changed forever. Research Many conspiracy theories have been developed concerning what happened to the World Trade Centers on September 11, 2001, but there are a select few that, similar to the truth, cannot be disproved without quite a bit of effort.
Skyscrapers are amazing! Architectural defeats. Wonders of the world. How are they able to withstand even the strongest of winds and earthquakes?
Black Swan Events are unplanned events that has a huge impact, these events can be environmental or financial events that are unpredictable or unexplainable.
The physical damage done to San Francisco due to the earthquake was extensive. The earthquake caused gas lines to rupture and chimneys to collapse which resulted in perhaps the greatest devastation from the earthquake, the fires. About fifty fires broke out around the city that in combination with the earthquake caused the destruction of about 28,000 buildings (The Great San Francisco Earthquake: One of America's Worst Urban Disasters. 2005). The fires continued to burn for four days because the water mains had burst; therefore, the hydrants had no water. Desperation sunk in and the fire department and military, having no water to stop the fires, used dynamite to create firebreaks. This ultimately backfired and led to the fires expanding. When the fires stopped, the city was left in ruins with 80% of it being destroyed (Dean. Pg 506).
Not surprisingly, the study showed that lower Manhattan absorbed the greatest damage. In addition to the thousands of lives that were lost in the destruction of the World Trade Center, the downtown region lost 100,000 jobs along with close to 30 percent of office space in the wake of the attack.
In the article “Terrorized by War on Terror” by Zbigniew Brzezinski, is about the attack on the World Trade Center on September 11, 2001. They hijacked four airplanes in mid-flight. The terrorists flew two of the planes into two the World Trade Center in New York City. The crash caused the buildings to catch fire and collapse causing the whole city to fill up with smoke and ash. Another plane destroyed part of the Pentagon in Arlington, Virginia. The fourth plane cr...
At 8:46 a.m., the United States witnessed the first terroristic attack of many to come when American Airlines flight 11 crashed into the World Trade Center’s North Tower in New York City. Flight 11 impacted the tower between floors 93 and 99 ...
On February 1, 2003, the Space Shuttle Columbia was lost due to structural failure in the left wing. On take-off, it was reported that a piece of foam insulation surrounding the shuttle fleet's 15-story external fuel tanks fell off of Columbia's tank and struck the shuttle's left wing. Extremely hot gas entered the front of Columbia's left wing just 16 seconds after the orbiter penetrated the hottest part of Earth's atmosphere on re-entry. The shuttle was equipped with hundreds of temperature sensors positioned at strategic locations. The salvaged flight recorded revealed that temperatures started to rise in the left wing leading edge a full minute before any trouble on the shuttle was noted. With a damaged left wing, Columbia started to drag left. The ships' flight control computers fought a losing battle trying to keep Columbia's nose pointed forward.
This all iron design made the bridge a lot heavier than it was designed for, which added more stress to the truss. This fact, by itself, wouldn’t cause any alarm. However, the bridge itself, was very poorly constructed. The members of the bridge were all different sizes, and they were not connected together properly. Due to the poor construction and eleven years of use, members of the bridge had started to bend due to the stress. Despite bridge engineers inspecting the bridge for eleven years, no one noticed these faults with the bridge. However, the ultimate cause of this collapse, was so tiny, only one of the investigators, after the collapse, noticed it. A tiny air hole was left during the construction of the bridge, “and grew with repeated stress over eleven years” (Escher, 2009). This hole would develop in a crack, due to the changing temperatures and the trains crossing it for over eleven years. This would weaken the overall strength of the bridge. The cold winter air and the weight of the train would ultimately prove to be too much, and the whole bridge came crashing
September 11, 2001 was a day that Americans and the world for that matter will not soon forget. When two planes went into the twin towers of the World Trade Center and two others went into the Pentagon and a small town in Pennsylvania, the world was rocked. Everyone in the United States felt very vulnerable and unsafe from attacks that might follow. As a result, confidence in the CIA, FBI, and the airlines were shaken. People were scared to fly after what had happened.
The Tacoma Narrows Bridge is perhaps the most notorious failure in the world of engineering. It collapsed on November 7, 1940 just months after its opening on July 1, 1940. It was designed by Leon Moisseiff and at its time it was the third largest suspension bridge in the world with a center span of over half a mile long. The bridge was very narrow and sleek giving it a look of grace, but this design made it very flexible in the wind. Nicknamed the "Galloping Gertie," because of its undulating behavior, the Tacoma Narrows Bridge drew the attention of motorists seeking a cheap thrill. Drivers felt that they were driving on a roller coaster, as they would disappear from sight in the trough of the wave. On the last day of the bridge's existence it gave fair warning that its destruction was eminent. Not only did it oscillate up and down, but twisted side to side in a cork screw motion. After hours of this violent motion with wind speeds reaching forty and fifty miles per hour, the bridge collapsed. With such a catastrophic failure, many people ask why such an apparently well thought out plan could have failed so badly?(This rhetorical question clearly sets up a position of inquiry-which iniates all research.) The reason for the collapse of the Tacoma Narrows Bridge is still controversial, but three theories reveal the basis of an engineering explanation. (Jason then directly asserts what he found to be a possible answer to his question.)
These type of loads should always be consider when determining fire department operations. Live loads must be estimated based on the use of the buildings as well as conditions such as rain and snow. The live load of a building will also be increased due to fire department operations. In some case, the added load due to fire department operations has lead to building collapse (Brannigan & Corbett, 2015).
According to National Geographic, “On average, a magnitude eight quake strikes somewhere every year and usually some 10,000 people die in earthquakes annually. Collapsing buildings claim by far the majority of lives”(1). Seismic retrofitting has helped protect existing infrastructure during earthquakes. Although results show that this method of earthquake proofing is successful, this solution does have negative impacts economically and culturally.