September 11, 2007

Some good came out of all that 9/11 pain.

I FELT for Leslie Roberts, the chief structural engineer of the World Trade Center. For over 4 years we suspected that the connections between the floor steel joists and the outside walls were a design flaw of his.The rumor was that he chose 'quick-connect' techniques for rapid crane assembly, trading construction speed for structural integrity. Many including myself thought that the floor open-web steel joists once heated just pulled out of their seat, precipitating a 'pancaking' of the floors of both towers. He was devastated, first for the victims, but also for the chance that he would never get to design anything major again. Just look into his eyes as you review this short preview of the extraordinary NOVA documentary shown today today on PBS and titled "Building on Ground Zero".



(You can see also view a sound-slideshow transcript of that production by clicking here)
It turns out that the second inquiry revealed the exact opposite, that the building was not only code compliant, but masterly well-designed. The floor joists were soundly welded to the outer walls, only the fall's violence just sheared off these connections. Unfortunately the lower more exposed chord of these floor joists lost its fire insulation during the initial explosion and eventually bowed down enough to draw in the outside structural walls by as much as 5 feet. Since these walls were already punctured by the planes, they fractured, intitiating the fall of the top segment of the building crushing all floors with incredible kinetic energy, like in a free fall.
The Engineer was finally vindicated, but at that time he had already left the country. He had been chosen as the chief engineer for China's new marvel, the 101-floor World finance Center in Shanghai. The architects Pedersen and Kohl could just not pass up the chance to hire the world's best high-rise structural designer. In a future post I will reveal the marvels of safety for that striking building. It does looks like a bottle opener, though. Possibly the device that was used to free the genie from the bottle of advanced engineering science.

After watching that Nova documentary, I FEEL GOOD for the man, a long time mentor. And to think that a part of these joists came from Canam Steel , my old friend Marcel Dutil's company! ( Here is a man who was born the same day as myself but who once said to me that by 19 he already had made ALL the mistakes in business I was still doing at 50.) His son Marc now runs the company with its 9 huge plants, the biggest producer of lightweight steel structural elements in Noth America.

But ....I digress as usual. Very sorry, families of the victims, you deserve more respect on that day of mourning. And after six years you certainly deserve a good monument! Why is it is it taking so long to get anything done on Ground Zero? With your army of lawyers, after having sued that brillant engineer and decent man out of the country, why not give Leslie Roberts a call in Shanghai? I bet he'd like to hear from you. He might invite you all for the upcoming inauguration party of the WFC. Hey! Free egg rolls!

4 comments:

Anonymous said...

VERY GOOD JACQUE. WONDER HOW LONG THESE HIGH RISES ON OUR COAST WILL STAND IF HIT BY EVEN A SMALL PLANE?

Jacques POIRIER said...

There is an excellent chance that they will stand. Just remember that Cirrus who hit a bldg in NYC, plioted by an NFL footbal player and his instructor. There is just way too little fuel there to create much of an explosion. The 'fluffy" insulation on the steel subfloor supports would most likely sustain it. Besides, because of your earthquake codes, West Coast high rises are mostly concrete floors.

ps; the same goes for our second floor here in Cantamar

Anonymous said...

YEARS AGO, THE HIGH RISE AT CALIFIA WAS STARTED AND I REMEMBER DRIVING BY IT AND IT WAS TILTED. EVENTUALLY THEY FINISHED IT AND NOW, MORE HIGH RISES ARE BEING BUILT NEXT TO IT. I'M SURE, HERE IN BAJA, THEY DON'T HAVE THE BUILDING CODES LIKE CALIF. YET, THAT NORTHRIDGE EARTHQUAKE HIT EVEN DOWN HERE. IT EVEN SHOOK MY TRAILER AND I THOUGHT FOR SURE THAT CALAFIA HIGH RISE WOULD GO DOWN. IT'S STILL THERE.

Jacques POIRIER said...

No kidding! Is it still tilted. That's a business. Think of the tourists at the leaning tower in Pisa