Structural Issues Doom WTC's Glass Facade

I run a high specification engineering CAD system. If I chose to do so, I could design parts that are impossible to make even with the most advanced manufacturing techniques. There is obviously an architect out there with a similar high specification architectural CAD system.

Design is about much more than drawing a picture. You have to understand the materials being used and the manufacturing processes that will be employed.

Designing for a one off is very different from designing for a large scale production environment. The architect may well have asked for lab samples of the glass panels that worked, and then found that making them in industrial quantities was not practical. If he/she didn't get lab samples, they shouldn't be paid for the work, and they should be ridiculed for wasting everyone's time.

Architects enjoy an inflated reputation. No self respecting engineer would design a major system without knowing that it could be constructed. This is not an isolated case.

The Millenium Bridge over the Thames in London resonated as people crossed it, making it impossible to walked on. On the day it opened, myself and a some other engineers sat in the pub watching the news coverage on television and agreed that adding hydraulic dampers would fix the problem. It took the world renown multi- awarded architect 18 months to come up with the same solution.

A concert hall in Birmingham, UK is built directly over an underground railway line, so it includes spring loaded foundations to dampen the noise of the trains from disrupting your enjoyment of a symphony. At the same time a similar size sports centre was under construction two hundred yards away. Swap the sites!! Do you care if you hear a few trains in the middle of a basket ball game?

This is not about politics, this is about bad design.

Sounds to me that the brainiac Architect was sold a bill of goods by the sales rep, and then specified the glass without having having it tested beforehand......nothing surprises me in regard to Architects practicing outside their sphere of knowledge and experience. Seen it happen way too many times, usually in regard to retaining walls, and building structural components. Possibly a reason to yank someone's state license to practice Architecture???

The architect will make no changes, he will merely "Allow his building to become what it wanted to be."

Two of my favorites; "It's only ten stories, don't make the columns any bigger than 8"x8"", and, "How the hell can a W14 measure 21"x16"? You should put the real size on your drawings."

Are there really any W14's (of whatever weight per foot) that measure 21" x 16"?

Nope, not as far as I can tell that such a W14 exists. What the 16" signifies is anybody's guess, but it is not in any way related to weight per linear foot of length. Maybe he can enlighten us what the 16" signifies?

According to the "AISC Manual of Steel Construction load and Resistance Factor Design, 3rd Edition", copyright 2001, the only W14 section that even has a 21" depth is a W14 x 665, where d = 21.6" and bf = 17.7".....close but no cigar! That's one monstrously heavy piece of steel! Most likely used for columns, not beams or girders.

There are three other W14 x wide flange beams that do have depths ranging from 16.0" to 16.7".

Beats me where the 16" is coming from, and I've been doing structural steel design for over 33 years. Of course, the 665 in the W14 x 665 designation is the weight per linear foot (units are: #/LF).

Gentlemen please. All I did was to pull a couple of round numbers that were in the ballpark for a particular highrise building, I don't recall the exact details of that conversation but I normally would round-up the size to allow for manufacturing tolerances, dimension and out-of-square etc..

I have used some W14x665s but they were supporting large coal bunkers inside of a large boiler house. There were heavier members in the manual at one time, the W14x730 for instance. A colleague used plated W14x730 columns to support a big coal fired boiler on one job that I reviewed, those were massive. There are even heavier W14 shapes available from some manufacturers if you look for them, I've seen a W14x808 in one listing.

Okay I'll give you that. Thanks for the explanation Passington.

I can assure you there was no intended foul on my part, just asking for a clarification.

And yes, the W14x808 is a massively huge piece of structural steel, and the heaviest WF 14 section normally milled/rolled.....it conforms to ASTM A6.

Have a great sunny day!

I worked across 17th Street in Philadelphia from One Liberty Place when they built it. You can imagine the lunch time watchers because we were a large company designing and building power plants and other heavy stuff. Interest peaked when we saw that the jumbo columns had full penetration butt welds. It was winter and they hung platforms and made tents with tarps while they worked away putting down a huge number of passes. QC was apparently good as they returned to burn some out and re-weld them.