Friday, August 15, 2008

Kevin Ran

Kevin Ryan knew nothing about how floor assemblies are tested by his own company Underwriters Laboratory. He rported that they tested the steel and it withstood 2000 deg for 3 and 4 hours. The UL tests floor and wall assemblies not the steel per se. The problem is that the long span floors used in the towers were never tested in their long span configuration of 60 feet. As any architect knows the longer span floors require either massive joists or beams uneconomical for high rise buildings or specially designed construction such as steel trusses. What most architects apparently don’t know is that lightweight, long span steel trusses fail at fire temperatures not yet compensated for in the codes. The standard furnace test can only handle 17 foot lengths of flooring. The furnace standards were set in the 30s 40s and 50s when about 15 feet was the standard span used in high rises. These older buildings used shorter spans, more robust columns and beams, stronger connections and better fireproofing then now. If a floor failed the pull-in (catenary) forces created by the short spans were easily handled by the strength of the rest of the structure. For this reason the codes allowed floors to have a shorter (3 hour) fire endurance rating than the columns or girders (4 hours). The 17 foot furnace test, currently still used, is meaningless for the longer spans. The main problem in the WTC flooring was due to the differential elongation (expansion) of the steel parts of the trusses. NIST’s studies found that the different expansion rates immediately deformed the steel parts, buckled the top chords and struts and disconnected the bond between the concrete slab and the joists. Greater thermal expansion of the bottom chords releases the tension and allows the cool top chord to sag until it acts as a cable in suspension creating pull-in forces on the columns. Contraction of sagging, long span steel flooring during the cool down faze after fire die down puts heavy pull-in loads on the connections. It is thought that Building 7 collapsed from this contraction in the beams disconnecting enough of them to affect column stability. The whole interior and core failed before the perimeter wall which came down as a unit at near free fall speed.


Arthur Scheuerman said...

BBC reporting error on Building 7 collapse.

In addition to the damage done to Building 7 by the heavy steel column trees that pealed off of the collapsing twin towers some of these steel columns penetrated the roads and broke the nearby water mains. There was no water supply immediately available and the Fire Department Chief in Command could not fight the numerous fires in Building 7 and ordered every one out of the building and out of the collapse zone (which was a large area including buildings and streets around building 7. Two huge buildings had already collapsed and when you can’t fight a fire because there is no water pressure it grows out of control all bets are off as to exactly what will happen and in one of these newer lightweight, open area high rise office buildings.

When anticipating possible collapse it is the procedure to discontinue interior operations and clear the building and establish a collapse zone around the building. The anticipation of collapse was a brilliant call and no lives were lost when the 47 story building collapsed a few hours after the evacuation order was given.*

You ask “How did the BBC know that the Towers were going to collapse?” The BBC didn't know. Did you ever hear a mistake made by a reporter? Or do you believe everything you are told by a TV reporter in the heat of an emergency? The BBC reporter on the air received an erroneous report that the tower had collapsed before it actually did and reported it well before the actual occurrence. It was a simple mistake.

I can imagine how it happened. Possibly a reporter on being told to evacuate the area by a rescue worker balked and to get him to move faster the worker told him the building is coming down. The reporter called his boss and told him the building 7 is coming down. The person receiving the call believed the building was already collapsing. It went out over the air as the building had already collapsed before the actual occurrence.

Of course if you believe that all the top fire protection engineers from the American Society of Civil Engineers (ASCE) and government scientists from National Institute of Standards and Technology (NIST) investigating the collapse are in on a conspiracy and also want to accuse the BBC, the NYC Fire Department, the NYC Police Department, the Red Cross and all the Government agencies controlling access Building 7 of being in on a secret controlled demolition even though there was no hard evidence than I would say you are grossly mistaken.

* This is a message from Chief of Department (ret.) Daniel Nigro, addressing the conspiracy theories surrounding the collapse of WTC7. Thank you very much for this statement, Mr. Nigro. The work you and your colleagues did will never be forgotten.

Release date: September 23, 2007

Regarding WTC 7: The long-awaited US Government NIST (National Institute of Standards and Technology) report on the collapse of WTC 7 is due to be published at the end of this year (although it has been delayed already a few times [ adding fuel to the conspiracy theorists fires!]). That report should explain the cause and mechanics of the collapse in great detail. Early on the afternoon of September 11th 2001, following the collapse of WTC 1 & 2, I feared a collapse of WTC 7 (as did many on my staff).

The reasons are as follows:

1 - Although prior to that day high-rise structures had never collapsed, The collapse of WTC 1 & 2 showed that certain high-rise structures subjected to damage from impact and from fire will collapse.
2. The collapse of WTC 1 damaged portions of the lower floors of WTC 7.
3. WTC 7, we knew, was built on a small number of large columns providing an open Atrium on the lower levels.
4. Numerous fires on many floors of WTC 7 burned without sufficient water supply to attack them.

For these reasons I made the decision (without consulting the owner, the mayor or anyone else - as ranking fire officer, that decision was my responsibility) to clear a collapse zone surrounding the building and to stop all activity within that zone. Approximately three hours after that order was given, WTC 7 collapsed.

Conspiracy theories abound and I believe firmly that all of them are without merit.

Regards, Dan Nigro
Chief of Department FDNY (retired)

Geezer Power said...

Well, I think that we should consider the pressure on Chief Nigro from the panel on the "Task Force for terrorism Preparedness" which was lead by non other than James Woolsey, ex head of the CIA.

(Mayor Michael R. Bloomberg and Fire Commissioner Nicholas Scoppetta today announced that former Director of the Central Intelligence Agency R. James Woolsey will serve as Chief Advisor to the newly created FDNY Terrorism Preparedness Taskforce. The Taskforce will examine and evaluate the FDNY's terrorism preparedness capabilities and will comprise a panel of leading nationally and internationally renowned experts on terrorism, including: Gregory H. Canavan, a nuclear physicist at the Los Alamos National Laboratory; Margaret Hamburg, a former New York City Health Commissioner; Dr. Joshua Lederberg, a winner of the Nobel Prize in Physiology; Daniel Nigro, Chief of Department for the FDNY; and Shabtai Shavit, a former Director of Israel's intelligence agency Mossad. Following the announcement, Mr. Woolsey and Commissioner Scoppetta joined FDNY chief officers and personnel in a visit to the quarters of Hazardous Materials Unit 1 and Squad Company 288 in Queens, for a presentation on the units' responsibilities, capabilities, and needs.)

More on The Meeting of the Chiefs

Arthur Scheuerman said...

The good thing is that NIST has an effective computer model to test whether a new or existing building is safe from collapse from fire. The architects and engineers should jump on this capability to assure any proposed or existing designs are safe. Another good thing is that any corrections proposed can be run through the computer and any tested for effectiveness. This NIST computer model shows that Building 7 was deconstructed by the heat of the uncontrolled fires expanding the long span steel floors, buckling beams, disconnecting structural steel connections, collapsing the floors and eventually buckling one key column which started the progressive collapse. The connections were so week that that the collapse of one column progressed across the core to take down the entire interior of the building. Now that’s an architectural and engineering problem. I want to hear what the Architects & Engineers for 9/11 truth think about a building that can loose one column which starts a progressive collapse that brings down the whole building. Design problem? They should be eager to get those computer models working instead of raving about some imaginary explosives having brought down these buildings.

Geezer Power said...

NIST report is seriously flawed

Arthur Scheuerman said...

You may say it’s highly unreasonable to believe that 4 steel constructed high-rise buildings collapsed from fire in one day? Well they all had one thing in common. Long Span steel composite floors. Long span steel beams have a magnified response to heat. They expand a longer distance than short span beams and they still have their full strength in the beginning of the expansion. NIST computer studies show that this strength while elongating can shear off the bolts connecting the beams to the columns or girders as the restrained beams expand. This strength can also crack the concrete slab at the shear studs and buckle the beam itself as the compression builds up during expansion.

A buckled or bowing (bowing occurs when the bottom flange of a steel beam expands faster than the top flange) long span (typically 40 to 50 feet) beam can impart large tension forces on the connections especially when the deflected beam begins to shrink as it cools. The fireproofing insulation thickness schedules in the Building Code were developed for the short span floors which were used in the older buildings and this insulation defended against weakness in the steel beams which occurs at higher temperatures 1100deg. F (about 600 deg. C). Low temperature expansion effects occur at temperatures below 400 deg. C and have not yet been compensated for in the codes. This deficiency in long span, high-rise office buildings is a new discovery discovered by the study of the collapse of the Twin Towers and Buildings 5 and 7 and was first illuminated by engineering computer studies. WTC 7 met all New York City codes and was not hit by any planes and was destroyed by a fire in ordinary combustible furnishings.

Another important characteristic of large open areas with combustible furnishings is that a fire can spread over the whole area and release a large quantity of heat if not extinguished immediately as by a working water spray system (sprinkler). The water spray systems in both towers and Building 7 were damaged by the forces of plane impacts or in Building 7 by the tower’s collapse impacts damaging the water mains in the streets.

The other thing about long span floors is that the builders have to relocate or remove the columns to get the open office areas that they wanted in the first place. When a column or columns fail under such large open area circumstances it or they may not be able to redistribute the floor loads to other columns and the collapse is likely to progress upwards. If the building is not protected against progressive collapse, global (total) collapse can ensue. Building 7 collapsed because one key interior column failed after the long span floors failed around it

Arthur Scheuerman
Ret. Battalion Chief, FDNY

Geezer Power said...


Arthur Scheuerman said...

About the “meteorite” recovered from ground zero. Everyone describes molten steel in the meteorite when it actually is deformed pieces of the bar joist flooring compacted with concrete and pieces of furnishings. This is careless language. Apparently people seeing steel deformed by heat immediately call it molten or melted steel. Melted or molten steel indicates a liquid state which occurs at higher temperatures than an ordinary fire can produce. The meteorite is a piece of pancaked concrete and steel floors fused together by high impacts. It contains charred pieces of books and paper which would not be present if heat high enough to melt steel existed anytime in the “meteorite”.

Geezer Power said...

And then there is always the little gems preserved in the police museum, that show the effects extremely high temperatures.