Wtc Form 100: Fill & Download for Free

I’m a structural engineer.Building fires don’t typically melt steel beams, but they do reduce the steel beam’s strength enough to make it FAIL and COLLAPSE.This is an old picture of a building where the steel beams softened enough to bend like cooked spaghetti:Here’s a picture of fire-damaged steel columns:During the Civil War, the North army would destroy southern railroad tracks by pulling up the iron rails and putting them in a campfire until they softened enough to wrap around a tree. The southerners called the bent rails “Sherman’s Neckties.” You don’t need a blast furnace to soften iron and steel (purified iron alloy), even a campfire can do it.Next time you go into the fire stairs at work, notice that all the steel structural members have fireproofing on them. Why are the beams and columns fireproofed?Fire makes steel weaken.The fireproofing cannot stop the SOFTENING of the steel, but it does delay it. The fireproofing in the WTC was completely defeated by being rammed by a jet plane and being subjected to a 1500 F jet fuel fire.A steel beam of the type used in the WTC is made from a very tough and ductile steel called “A36 steel.” It has a “yield stress” of 36,000 psi. That’s the stress at which it yields and stretches and buckles.The “tensile strength” is the the ultimate stress where it fractures and tears, which for A36 steel is 58,000 psi.See how this bolt is necked down and stretched? Someone applied load to it until the stress reached the yield point and then the steel stretched and deformed. Structural steel is DUCTILE, which means it deforms and stretches a lot before it fractures. Like this bolt.A steel beam or column made from A36 steel beam is designed to carry a stress of 20,000 psi of maximum load, which leaves a safety factor of an extra 16,000 psi.20,000 psi load + 16,000 psi safety factor = 36,000 psi yield = A36 steel.For example, if you have a column that’s 100 square inches in area, if it’s braced properly it will safely hold 100 sq in x 20,000 psi = 2,000,000 lbs.Suppose that a fire starts heating and weakening the steel. The yield strength of the steel will slowly drop down from 36,000 psi to 20,000 psi, at which time the steel column will yield and deform and buckle and stretch under the normal 20,000 psi load even though it’s not melted.Once that happens, it’s game over. The dynamic load of the upper floors pancaking onto the next story will crush the columns and start a chain reaction. The force of a falling load is many times higher than a stationary load. Try it. Place a bowling ball on your foot. It won’t hurt. Now lift it one story high and drop it on your foot. Then report to the hospital for your cast and crutches. (Don’t actually try this, your foot will not like it.)Once the steel structural members in the WTC softened from 36,000 psi yield to 20,000 yield, the members buckled under their normal applied loading and dumped their load onto the next floor down. And then the pancaking of the stories started.Don’t forget - the building took millions and millions of energy units (BTUs) to lift into the sky, and all that energy was stored in the building as “potential energy.” The collapse of the initial story released the potential energy and it pulverized everything below it.Suppose that your chimney falls off the roof of your house and hits your car hood and dents it. Where did the energy to to dent your car hood come from? Well, it came from the legs of the workmen who carried the bricks up to your roof. That leg energy was stored in the bricks as “potential energy” and released when the chimney fell off the roof.For another example, suppose your grandfather puts a bowling ball up high in a closet. 30 years later, the ball rolls off the shelf and cracks your skull. You know where the energy to crack your skull came from? Your grandfather’s arms. When he lifted the ball up high onto the closet shelf, he stored energy in the ball. When the ball rolled off the shelf, the potential energy was turned into motion energy, the falling ball. And the energy in the falling ball cracked your skull bone.The WTC did the exact same thing, except the potential energy wasn’t 300 lbs of bricks lifted 30 feet, it was 500,000 tons lifted an average of 1,000 feet up. LOTS of energy, all you’d ever need to turn the whole building into rubble.You know what the great thing about structural engineering is?It’s very mathematically deterministic. You can perform an investigation and PROVE what’s going on using physics and math. It’s not like a divorce court where people can lie their ass off and be believed. If your building falls down, you can hire a structural engineer and PROVE how it happened.Here’s what a typical structural collapse modeled with finite element analysis looks like:If the WTC fire wasn’t sufficient to bring down the building, every competent structural engineer on the planet earth would be saying so right now. These things are not a matter of OPINION, they’re a matter of PROVABLE scientific FACT.IF THERE WAS A CONSPIRACY, THE ENEMIES OF THE USA ALL OVER THE WORLD WOULD HAVE THEIR EXPERTS PROVE IT WITH COMPUTER MODELLING.A conspiracy theory won’t stand up to a Finite Element Analysis.Here’s a very detailed FEM analysis of the WTC that was done at Purdue University:And here is another:

Bad form. Really?His scores in last 9 international innings89,63,09,40,85,74,04,11,72 at an aversge of 49.66!Does this resemble the numbers of an out of form batsman? Surely not. But why does it feel like he is out of form? Because he is Virat Kohli. And Virat Kohli is expected to score daddy hundereds and not daddy fifties. The last VIRAT hundred came way in 2019, 31 innings ago ! How long will this streak continue? Hope today is the last day. Fingers crossed.Edit: Answer has crossed 1k. Virat still hasn't scored 100.Still not crossed. WTC final.Fingers crossed.

The four greatest national tragedies/crises of the past 100 years were 9/11, Coronavirus, Pearl Harbor and the stock market crash. One of them (Pearl Harbor) occurred with a Democrat in office. Why did 3 of 4 occur with Republicans in office? No reason, just coincidence. 9/11 still happens with Gore in office. Covid-19 still happens with Hillary Clinton in office.The Anthrax scare while important is not in the same league with these other events. If you want to include it, then you need to also include the 1993 WTC attack and Iran hostage situation both of which were bigger deals than the Anthrax scare and occurred with Democrats in office.