Page 5 of 30 FirstFirst ... 3456715 ... LastLast
Results 41 to 50 of 297
Like Tree28Likes

Thread: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

  1. #41
    Devourer of Poor Children
    DrunkenAsparagus's Avatar
    Join Date
    Aug 2009
    Location
    DC
    Last Seen
    06-19-14 @ 06:43 PM
    Gender
    Lean
    Libertarian
    Posts
    4,496
    Likes Received
    1880 times
    Likes Given
    3271

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by creativedreams View Post
    Exactly.....follow the connection trail to the propaganda that is intentionally misleading.

    The propaganda spewed via the vehicles of...History Channel and Popular Mechanics target average couch potato Americans too lazy to do their own research and intentionally mislead by focusing on the floor trusses and ignoring the many vertical support columns that run from bedrock to the top floor in the core.
    Yes because, structural engineers, intlligence experts, people who are experts on actual demolitions, and people who were actually freaking there don't know as much as people like Alex Jones, Fetzer, and whoever you manage to pull out of the depths of cyberspace. I didn't say that they or anyone has all of the answers, but they shoot down the most retarded of the theories.

    Quote Originally Posted by creativedreams View Post
    Somehow these core columns were blown out of the way fast enough all the way down for the top floor to hit the ground almost as fast as a ball would.
    This might have to do with the incredible downwardforce that accompinied the failling of the building
    "Doubleplusungood"

    George Orwell

  2. #42
    Guru
    Skateguy's Avatar
    Join Date
    Dec 2009
    Location
    Houston/Heights
    Last Seen
    02-07-12 @ 06:01 PM
    Gender
    Lean
    Independent
    Posts
    2,571
    Likes Received
    385 times
    Likes Given
    16

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by DrunkenAsparagus View Post
    Yes because, structural engineers, intlligence experts, people who are experts on actual demolitions, and people who were actually freaking there don't know as much as people like Alex Jones, Fetzer, and whoever you manage to pull out of the depths of cyberspace. I didn't say that they or anyone has all of the answers, but they shoot down the most retarded of the theories.



    This might have to do with the incredible downwardforce that accompinied the failling of the building
    "Boing"--sorry wrong answer---next contestant.
    "Don't be particular bout nothin, but the company you keep"

  3. #43
    Devourer of Poor Children
    DrunkenAsparagus's Avatar
    Join Date
    Aug 2009
    Location
    DC
    Last Seen
    06-19-14 @ 06:43 PM
    Gender
    Lean
    Libertarian
    Posts
    4,496
    Likes Received
    1880 times
    Likes Given
    3271

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by Skateguy View Post
    "Boing"--sorry wrong answer---next contestant.
    Great rebuttle
    "Doubleplusungood"

    George Orwell

  4. #44
    Guru
    Skateguy's Avatar
    Join Date
    Dec 2009
    Location
    Houston/Heights
    Last Seen
    02-07-12 @ 06:01 PM
    Gender
    Lean
    Independent
    Posts
    2,571
    Likes Received
    385 times
    Likes Given
    16

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by DrunkenAsparagus View Post
    Great rebuttle
    I'm a quick study--if it works for their side, it should work for mine. --If you have no facts to wage a rebuttal---just say they are stupid, misinformed, morons, and are just out and out, wrong. thought I would give it a try.
    "Don't be particular bout nothin, but the company you keep"

  5. #45
    Professor
    I_Gaze_At_The_Blue's Avatar
    Join Date
    Aug 2009
    Location
    Bonnie Scotland !!!
    Last Seen
    11-22-12 @ 12:42 PM
    Gender
    Lean
    Slightly Conservative
    Posts
    1,499
    Likes Received
    367 times
    Likes Given
    661

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by Skateguy View Post
    The core of the buildings, were like most all frame work for modern buildings. Columns of steel, fastened together with cross bracing, to make a rigid structure. --
    Are you using "cross bracing" as to be taken to mean diagonal bracing ???

    There was diagonal bracing in the Twin Towers ... there was also horizontal.

    Some more information would be helpful, pretty please !!!

    Quote Originally Posted by Skateguy View Post
    No, it is not solid like a tree.--sorry if that one went over your head, as that was not my intent. I was simply trying to break it down as simple as possible for you. ---but if you can't see what I was referring to, I may be wasting my breath.
    Afraid that nothing went over my head ...

    However I believe, in a rather cock-handed way, you are referring to the RIGIDITY of a tree as opposed to solidity.

    Trees as structures aside from a degree of rigidity also NEED a degree of FLEXIBILITY.

    Were they wholly rigid and inflexible, without give or elasticity they would undoubtably break in the wind.

    Just like the Towers ... there has to be a certain amount of give factored in too ... the wind forces acting upon the Towers were considerable and they had to, by way of a degree of flexibility resist them.

    Are you aware that the wind speed DOUBLES for every ten-fold increase in altitude ... meaning that higher level winds (gradient wind) travel faster than winds at ground level !!!

    Suspect you didn't !!!

    Quote Originally Posted by Skateguy View Post
    It is just simple Structural design, --nothin new here. --did you build with "erector sets", when you were young? If not, it would explain your seemingly lack of basic engineering.--
    I take it you mean a Lego kit ... well that would be a no, being a gurl I was much more interested in my ponies !!!

    However I beg to differ regarding lack of skills ... the basic engineering is simple to grasp, nothing I have previously said would be misunderstood by those with relevent qualifications.

    Nothing I have said would not be able to be found in engineering text !!!

    Quote Originally Posted by Skateguy View Post
    You don't have to have a degree to understand it.---and I'm not trying to be disrespectful with my comments.
    I again beg to differ ... detailed knowledge can only come from a greater level of learning.

    Some things actually NEED a good understanding of the subject matter in the first place ... less knowledge = less understanding.

    Über simple !!!

    None taken ... it takes much more than that to even start to get to me ... this ain't my first ride, me laddie !!!

    (I am such a fannybaws I managed to delete this and had to write it all out again as too busy tending Farmville ... )
    Parva leves capiunt animas !!!

  6. #46
    Devourer of Poor Children
    DrunkenAsparagus's Avatar
    Join Date
    Aug 2009
    Location
    DC
    Last Seen
    06-19-14 @ 06:43 PM
    Gender
    Lean
    Libertarian
    Posts
    4,496
    Likes Received
    1880 times
    Likes Given
    3271

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by Skateguy View Post
    I'm a quick study--if it works for their side, it should work for mine. --If you have no facts to wage a rebuttal---just say they are stupid, misinformed, morons, and are just out and out, wrong. thought I would give it a try.
    My comment wasn't a specious plea to authority. These people took time to explain things better than these other people. Many people in the documentery were actually there. The Truthers pull forward people with little knowledge of what they're talking about. I'm not saying that their authority always makes them right, but I'll trust a heart surgeon to tell me what's wrong with my heart over a classics professor.

    Again noncredible source=failed argument
    "Doubleplusungood"

    George Orwell

  7. #47
    Guru
    Skateguy's Avatar
    Join Date
    Dec 2009
    Location
    Houston/Heights
    Last Seen
    02-07-12 @ 06:01 PM
    Gender
    Lean
    Independent
    Posts
    2,571
    Likes Received
    385 times
    Likes Given
    16

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by I_Gaze_At_The_Blue View Post
    Are you using "cross bracing" as to be taken to mean diagonal bracing ???

    There was diagonal bracing in the Twin Towers ... there was also horizontal.

    Some more information would be helpful, pretty please !!!



    Afraid that nothing went over my head ...

    However I believe, in a rather cock-handed way, you are referring to the RIGIDITY of a tree as opposed to solidity.

    Trees as structures aside from a degree of rigidity also NEED a degree of FLEXIBILITY.

    Were they wholly rigid and inflexible, without give or elasticity they would undoubtably break in the wind.

    Just like the Towers ... there has to be a certain amount of give factored in too ... the wind forces acting upon the Towers were considerable and they had to, by way of a degree of flexibility resist them.

    Are you aware that the wind speed DOUBLES for every ten-fold increase in altitude ... meaning that higher level winds (gradient wind) travel faster than winds at ground level !!!

    Suspect you didn't !!!



    I take it you mean a Lego kit ... well that would be a no, being a gurl I was much more interested in my ponies !!!

    However I beg to differ regarding lack of skills ... the basic engineering is simple to grasp, nothing I have previously said would be misunderstood by those with relevent qualifications.

    Nothing I have said would not be able to be found in engineering text !!!



    I again beg to differ ... detailed knowledge can only come from a greater level of learning.

    Some things actually NEED a good understanding of the subject matter in the first place ... less knowledge = less understanding.

    Über simple !!!

    None taken ... it takes much more than that to even start to get to me ... this ain't my first ride, me laddie !!!

    (I am such a fannybaws I managed to delete this and had to write it all out again as too busy tending Farmville ... )
    Sorry, I didn't know you were a Girl. My bad.--Yes the Frame work does have built in flex in it, for the reasons you describe. so it won't fall or break. I was speaking of Horizontal cross members. Many buildings do not use diagonals, though I think they should. Could be because it would make them to ridged, with out enough flex. Conjecture on my part here. --An "Erector set" is small metal beams and girders that boys made structures like we are speaking of with. They teach us basic engineering principles at an early age. that hold true as time goes by.---I don't have an Engineering degree, yet I do hold one "United States Patent" for something I engineered. I have no business degree, yet have run a successful business for thirty years. And I worked for 20 plus years as a Journeyman Machinist, and Inspector. Primarily with Pumps and gas turbine engines. ---so I have a little understanding of the working of the physical world.
    Last edited by Skateguy; 01-12-10 at 03:35 PM.
    "Don't be particular bout nothin, but the company you keep"

  8. #48
    Professor
    I_Gaze_At_The_Blue's Avatar
    Join Date
    Aug 2009
    Location
    Bonnie Scotland !!!
    Last Seen
    11-22-12 @ 12:42 PM
    Gender
    Lean
    Slightly Conservative
    Posts
    1,499
    Likes Received
    367 times
    Likes Given
    661

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by Skateguy View Post
    Sorry, I didn't know you were a Girl. My bad.--Yes the Frame work does have built in flex in it, for the reasons you describe. so it won't fall or break. I was speaking of Horizontal cross members. Many buildings do not use diagonals, though I think they should. Could be because it would make them to ridged, with out enough flex. Conjecture on my part here. --An "Erector set" is small metal beams and girders that boys made structures like we are speaking of with. They teach us basic engineering principles at an early age. that hold true as time goes by.---I don't have an Engineering degree, yet I do hold one "United States Patent" for something I engineered. I have no business degree, yet have run a successful business for thirty years. And I worked for 20 plus years as a Journeyman Machinist, and Inspector. Primarily with Pumps and gas turbine engines. ---so I have a little understanding of the working of the physical world.
    Not a worry, but the little pink symbol beneath my profile info is usually a clue ...

    It it good to know some of your background Skategy, for some reason I thought you were younger ...

    Your Erector set is what we call "Meccano" over here ... brilliant toy, and although I get what you are saying about its ability to teach some basic engineering principles, that is only if it is explained to you as well.

    You can build some pretty impossible in the real world, shapes with it ... so unless you have had the added explanation and teaching you may well have a distorted or flawed understanding !!!

    For myself, I trained as a Dental Surgeon through the RAF (Royal Air Force) and matriculated through the Scottish University system ... and although a medical field you still had to have training in engineering principles, particularly mechanical ... as well as various military field medicine skills, as being classed non-combatent you still had to train for being called upon, a bit like your MASH hospital stuff !!!

    In applied dentistry you still need to understand engineering, although on a micro-scale ... cantilevers, abutments, pressure, stress, pivots, fracturing, etc ... e.g your TMJ (temporomandibular joint) or jaw bone is a double-hinge joint, allowing for anterior/posterior and lateral movement !!!

    Measuring and manufacturing a dental bridge is not strictly just a medical proceedure, but also an engineering feat in minature !!!

    So although having spend my career in micro, I can still scale-up and apply those principles ... and I think that is where many people go wrong ...
    they cannot scale-up ... so to them common sense tells them that something twice the size is twice as strong, when that is not strictly true.

    To use a dental analogy ... the bite FORCE exerted by the human jaw can be averaging around 160 lbs of pressure, with it at maximum, in some cases, at over 970 lbs, with the incisors maxing out at 34/5 lbs !!!

    Whilst bite PRESSURE can be up to over 5,000 psi !!!

    Now, in people who grind their teeth, that can INCREASE by factors of 7 to 10times that ... but do they, therefore, "need" to be 7 to 10 times bigger to do it ???

    Well, obviously, that's a no ... and yet that is what many people are arguing regarding this, applying what to them may be common sense rules, but they count for nothing unless you truly and fully understand the differences between exponential, linear and logarithmic measurments, etc.

    As a 9/11 related example let's use the Boeing 707 which was the aircraft used to calculate the impact forces in the 1964 study of the Towers.

    And even IF the 767 which hit on 9/11 was the exact same size and weight the as the 707, the simple fact that is was travelling faster INCREASES the damage.

    Now, how many people here would know, automatically, that even for an object the exact same weight and mass ... by doubling the speed(velocity) you QUADRUPLE the kinetic energy !!!

    So the exact same object, by just DOUBLING velocity would impact with FOUR TIMES more energy as before !!!

    Just like your bullet in my other post ... whether in your hand or a chamber it has the same weight and mass but by "changing" velocity you "change" the levels of damage ... simple stuff ...

    ~~~~~~~~~~

    As a funny aside ... our nursing service in the RAF is known as PMRAFNS (Princess Marys' Royal Air Force Nursing Service) an acronym which we renamed Pull My RAF Nickers Sideways !!!

    How naughty ...

    Btw, we still have travelling Journeymen from Germany, who travel all over, for just over 3 years, developing their various skills until the level of Master Craftsman, known as Wandergesellen.

    They are the best, they are meticulous at everything, even down to time-keeping and cleanliness, they have to wear an old-fashioned uniform, are not allowed to marry during the apprenticeship, yet must kiss (nicely) every woman they meet and are incredibly polite ... so if ever you are building a house !!!

    Presse - Rechtschaffene Fremde Maurer- und Steinhauergesellen

    Journeymen find their way to Estonia

    Parva leves capiunt animas !!!

  9. #49
    Guru
    Skateguy's Avatar
    Join Date
    Dec 2009
    Location
    Houston/Heights
    Last Seen
    02-07-12 @ 06:01 PM
    Gender
    Lean
    Independent
    Posts
    2,571
    Likes Received
    385 times
    Likes Given
    16

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Quote Originally Posted by I_Gaze_At_The_Blue View Post
    Not a worry, but the little pink symbol beneath my profile info is usually a clue ...

    It it good to know some of your background Skategy, for some reason I thought you were younger ...

    Your Erector set is what we call "Meccano" over here ... brilliant toy, and although I get what you are saying about its ability to teach some basic engineering principles, that is only if it is explained to you as well.

    You can build some pretty impossible in the real world, shapes with it ... so unless you have had the added explanation and teaching you may well have a distorted or flawed understanding !!!

    For myself, I trained as a Dental Surgeon through the RAF (Royal Air Force) and matriculated through the Scottish University system ... and although a medical field you still had to have training in engineering principles, particularly mechanical ... as well as various military field medicine skills, as being classed non-combatent you still had to train for being called upon, a bit like your MASH hospital stuff !!!

    In applied dentistry you still need to understand engineering, although on a micro-scale ... cantilevers, abutments, pressure, stress, pivots, fracturing, etc ... e.g your TMJ (temporomandibular joint) or jaw bone is a double-hinge joint, allowing for anterior/posterior and lateral movement !!!

    Measuring and manufacturing a dental bridge is not strictly just a medical proceedure, but also an engineering feat in minature !!!

    So although having spend my career in micro, I can still scale-up and apply those principles ... and I think that is where many people go wrong ...
    they cannot scale-up ... so to them common sense tells them that something twice the size is twice as strong, when that is not strictly true.

    To use a dental analogy ... the bite FORCE exerted by the human jaw can be averaging around 160 lbs of pressure, with it at maximum, in some cases, at over 970 lbs, with the incisors maxing out at 34/5 lbs !!!

    Whilst bite PRESSURE can be up to over 5,000 psi !!!

    Now, in people who grind their teeth, that can INCREASE by factors of 7 to 10times that ... but do they, therefore, "need" to be 7 to 10 times bigger to do it ???

    Well, obviously, that's a no ... and yet that is what many people are arguing regarding this, applying what to them may be common sense rules, but they count for nothing unless you truly and fully understand the differences between exponential, linear and logarithmic measurments, etc.

    As a 9/11 related example let's use the Boeing 707 which was the aircraft used to calculate the impact forces in the 1964 study of the Towers.

    And even IF the 767 which hit on 9/11 was the exact same size and weight the as the 707, the simple fact that is was travelling faster INCREASES the damage.

    Now, how many people here would know, automatically, that even for an object the exact same weight and mass ... by doubling the speed(velocity) you QUADRUPLE the kinetic energy !!!

    So the exact same object, by just DOUBLING velocity would impact with FOUR TIMES more energy as before !!!

    Just like your bullet in my other post ... whether in your hand or a chamber it has the same weight and mass but by "changing" velocity you "change" the levels of damage ... simple stuff ...

    ~~~~~~~~~~

    As a funny aside ... our nursing service in the RAF is known as PMRAFNS (Princess Marys' Royal Air Force Nursing Service) an acronym which we renamed Pull My RAF Nickers Sideways !!!

    How naughty ...

    Btw, we still have travelling Journeymen from Germany, who travel all over, for just over 3 years, developing their various skills until the level of Master Craftsman, known as Wandergesellen.

    They are the best, they are meticulous at everything, even down to time-keeping and cleanliness, they have to wear an old-fashioned uniform, are not allowed to marry during the apprenticeship, yet must kiss (nicely) every woman they meet and are incredibly polite ... so if ever you are building a house !!!

    Presse - Rechtschaffene Fremde Maurer- und Steinhauergesellen

    Journeymen find their way to Estonia

    Great information. thanks for sharing. --We could use some of that "Old School Craftsmanship" in America now days. All we know how to do, is make money, and text. We have forgotten our way as Builders.
    "Don't be particular bout nothin, but the company you keep"

  10. #50
    Banned
    Join Date
    Dec 2008
    Location
    Timbuktu
    Last Seen
    01-30-12 @ 06:09 AM
    Gender
    Lean
    Slightly Conservative
    Posts
    2,730
    Likes Received
    232 times
    Likes Given
    301

    Re: 47 vertical support columns in core of each Twin Tower from bedrock to top floor

    Here is some information on the Twin Towers actually being designed to withstand a possible plane impact during foggy conditions....

    9-11 Research: Towers' Design Parameters

    Contrary to widely promoted misconceptions, the Boeing 767-200s used on 9/11/01 were only slightly larger than 707s and DC 8s, the types of jetliners whose impacts the World Trade Center's designers anticipated



    The above graphic from Chapter 1 of FEMA's Report shows the sizes of a 707 and a 767 relative to the footprint of a WTC tower. 1 Flight 11 and Flight 175 were Boeing 767-200s. Although a 767-200 has a slightly wider body than a 707, the two models are very similar in overall size, weight and fuel capacity.


    property Boeing 707-320.............Boeing 767-200
    fuel capacity 23,000 gallons..........23,980 gallons
    max takeoff weight 328,060 lbs.....395,000 lbs
    empty weight 137,562 lbs............179,080 lbs
    wingspan 145.75 ft.....................156.08 ft
    wing area 3010 ft^.....................2 3050 ft^2
    length 152.92 ft.........................159.17 ft
    cruise speed 607 mph..................530 mph


    Given the differences in cruise speeds, a 707 in normal flight would actually have more kinetic energy than a 767, despite the slightly smaller size. Note the similar fuel capacities of both aircraft. The 767s used on September 11th were estimated to be carrying about 10,000 gallons of fuel each at the time of impact, only about 40% of the capacity of a 707.

    Statements by Engineers
    Engineers who participated in the design of the World Trade Center have stated, since the attack, that the Towers were designed to withstand jetliner collisions. For example, Leslie Robertson, who is featured on many documentaries about the attack, said he "designed it for a (Boeing) 707 to hit it." 2 Statements and documents predating the attack indicate that engineers considered the effects of not only of jetliner impacts, but also of ensuing fires.

    John Skilling
    John Skilling was the head structural engineer for the World Trade Center. In a 1993 interview, Skilling stated that the Towers were designed to withstand the impact and fires resulting from the collision of a large jetliner such as Boeing 707 or Douglas DC-8.

    Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed, ... The building structure would still be there.

    A white paper released on February 3, 1964 states that the Towers could have withstood impacts of jetliners travelling 600 mph -- a speed greater than the impact speed of either jetliner used on 9/11/01.

    The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707—DC 8) traveling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact.

    The Richard Roth Telegram
    On Feburary 13, 1965, real estate baron Lawrence Wien called reporters to his office to charge that the design of the Twin Towers was structurally unsound. Many suspected that his allegation was motivated by a desire to derail the planned World Trade Center skyscrapers to protect the value of his extensive holdings, which included the Empire State Building. In response to the charge, Richard Roth, partner at Emery Roth & Sons, the architectural firm that was designing the Twin Towers, fired back with a three-page telegram containing the following details.

    "THE STRUCTURAL ANALYSIS CARRIED OUT BY THE FIRM OF WORTHINGTON, SKILLING, HELLE & JACKSON IS THE MOST COMPLETE AND DETAILED OF ANY EVER MADE FOR ANY BUILDING STRUCTURE. THE PRELIMINARY CALCULATIONS ALONE COVER 1,200 PAGES AND INVOLVE OVER 100 DETAILED DRAWINGS. "

    " BECAUSE OF ITS CONFIGURATION, WHICH IS ESSENTIALLY THAT OF A STEEL BEAM 209' DEEP, THE TOWERS ARE ACTUALLY FAR LESS DARING STRUCTURALLY THAN A CONVENTIONAL BUILDING SUCH AS THE EMPIRE STATE BUILDING WHERE THE SPINE OR BRACED AREA OF THE BUILDING IS FAR SMALLER IN RELATION TO ITS HEIGHT."

    " THE BUILDING AS DESIGNED IS SIXTEEN TIMES STIFFER THAN A CONVENTIONAL STRUCTURE. THE DESIGN CONCEPT IS SO SOUND THAT THE STRUCTURAL ENGINEER HAS BEEN ABLE TO BE ULTRA-CONSERVATIVE IN HIS DESIGN WITHOUT ADVERSELY AFFECTING THE ECONOMICS OF THE STRUCTURE."

    At the time the Twin Towers were built, the design approach of moving the support columns to the perimeter and the core, thereby creating large expanses of unobstructed floor space, was relatively new, and unique for a skyscraper. However, that approach is commonplace in contemporary skyscrapers.

    Frank Demartini's Statement
    Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.

    The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.

    Demartini, who had an office on the 88th floor of the North Tower, has been missing since the 9/11/01 attack, having remained in the North Tower to assist in the evacuation. 6 Demartini had first worked at World Trade Center when Leslie E. Robertson Associates hired him to assess damage from the truck bombing in 1993.

    Like All Skyscrapers, the Twin Towers Were Over-Engineered
    One aspect of engineering that is not widely understood is that structures are over-engineered as a matter of standard practice. Steel structures like bridges and buildings are typically designed to withstand five times anticipated static loads and 3 times anticipated dynamic loads. The anticipated loads are the largest ones expected during the life of the structure, like the worst hurricane or earthquake occurring while the floors are packed with standing-room-only crowds. Given that September 11th was not a windy day, and that there were not throngs of people in the upper floors, the critical load ratio was probably well over 10, meaning that more than nine-tenths of the columns at the same level would have to fail before the weight of the top could have overcome the support capacity of the remaining columns.

    There is evidence that the Twin Towers were designed with an even greater measure of reserve strength than typical large buildings. According to the 1964 white paper cited above, a Tower would still be able to withstand a 100-mile-per-hour wind after all the perimeter columns on one face and some of the columns on each adjacent face had been cut. Also, John Skilling is cited by the Engineering News Record for the claim that "live loads on these perimeter columns can be increased more than 2000% before failure occurs."
    Last edited by creativedreams; 01-15-10 at 05:27 AM.

Page 5 of 30 FirstFirst ... 3456715 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •