You said this:

I am trying to see what you know to back that up.

psik

I think it is easy, but I think landing in driving rain at 2000 RVR is easy, and building computers is easy. There is no excuse for not estimating the masses you want to know after 13 years.

If I was obsessed with mass, I would have an estimate before 13 years passed, not complaining about it for years. It is easy as show in the post above.

What I wrote last night watching Bad Teacher...

""What was the plate thickness at floor 9, 3 inches? 109, was it .25 inches? I wonder if 1/2 inch steel would have stopped the aircraft at the shell? I think it might (stop the aircraft)... however, the estimate, you have one right? If not... Next you need to look up the density/mass of steel, then dimensions, etc, and then you have it. The concrete is easier... 4 inch floors, density/mass of concrete. How much help do you need? Try starting with this, and see what you get. I would look up more for you, but I am copying slides with my digital camera and have to trim the walnut trees, and cut down an oak tree... I will help when I can, but it is easy to do, but it takes time and effort, and much more rewarding if you try on your own. My model has the WTC collapsing once a floor is loaded past 30,000,000 pounds, and it can't stop until the ground. My model is simple, and has the collapse time of 12.08 seconds. I can almost do my model in my head, I needed excel for the collapse time.

Do 12 floors in your estimate weigh more than 30,000,000 pounds? You have estimates for floors mass after 13 years.

What did you get? On the mass of a perimeter wall panel? Are you limiting it to one floor, or the whole panel, three floors?

Did you know some of the best ways to start finding information on the WTC structure is from 911 truth sources, especially ones with references to real work. Like this...

http://911research.wtc7.net/wtc/arch/perimeter.html
I think I saw this over 5 years ago, did you find it too? Did it help estimate your needs?

Models for floors, the floors weigh the same (you could use washers), one estimate, the connections remain the same, each floor fails at over 29,000,000 pounds, an easy model. 911 failure mode, a floor is over loaded, fails, the mass moves to the next floor, the floor fails, each impact can be modeled as a momentum transfer, the debris mass moves faster each floor due to g, and the velocity is slowed by each increase in mass as each floor fails and joins the falling debris mass. What would slow the destruction of the core and shell is the fact the shell plate thickness goes from 1/4 inch to 3 or 4 inches at the base, and that changes a lot. Do you model the shell, or core; the floor connections are the constant, and floors would fail to the bottom, if the load exceeds 29,000,000 pounds, and a moving debris pile would not have to be that much mass to break a floor from the core and shell.

Once started I can't see how you can stop lower floors from seeing loads in excess of their load limits; is this why your model fails, a floor still fails at the same weight all the way down (maintenance floors can hold more right... )

The big problem might be, understanding the shell and the core can hold all 110 floors, plus more, they have no problem holding up the WTC, but the floors can't hold more debris than 11 or 12 floors, then it fails. Understanding the WTC has to have the floors holding the core to the shell as a system; this is how the WTC was built, a floor at a time, it was a system which made it the strongest building around; anything which separates the floors from the shell or the core would destroy the WTC system.

If you have not estimated the WTC masses of interest after 13 years, NIST has some stuff you could use too, but you have to dig through NIST. Or libraries, after 13 years I think a good estimate could be made. Yes, I would say going to the moon and back is hard, but estimating the WTC masses is easy, it is all relative...

Someone has all the floor plans, blue prints...

In your model, what can a floor (the washer) hold in weight? How many washers/floors can your washer model hold. The WTC the magic number is 11 or 12, then the washer/floor fails. Thus a proper washer model would collapse to the ground. ""

Wow, don't post watching Bad Teacher... Good luck with your estimates

If you model washer floor can hold more than 12 washers, it does not model the WTC.

It easy to estimate stuff, you do the research, and then calculate. Post 425 gives some clues. Do you think easy means 10 seconds, or what? You might need to spend a semester working on it, or a week, but there is no excuse for complaining about the mass when you can estimate it with knowledge.

I would post the photos I am working on, slides to digital using a DSLR, at 36 mega pixels I can see the grain (I think) on the

Ektachrome/Kodachrome slides, but it would not help your estimates, the estimates you want, your estimates. - it is off topic, and something I find easy to do for real. We do those things we find important, and I think estimating the WTC masses you want is easy, I choose to do those things I want to do. I don't have any problems finding enough to estimate what you want, but I will not be doing your work for you. Good luck