Did The Building Do It?- results to be published in an academic journal

[greyl]

Did The Building Do It?
Karen Auguston Field, Editor-in-Chief -- Design News, August 17, 2006
<snip
Now, as the five-year anniversary of the World Trade Center attack draws near, Astaneh-Asl finally expects to have the results of his analysis published in an academic journal. The project, requiring thousands of hours to complete, was self-funded and conducted by Astaneh-Asl, his students, and analysts from the MSC.Software Corporation, which donated the structural analysis software (MD Nastran and Dytran).
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He also noted that designers chose to fabricate many of the building columns out of very high strength steel <90 ksi steel as opposed to the more typical 36-65 ksi steel>. “This is not allowed by the structural design codes then and is still notallowed in current codes,” he stressed. “But the World Trade Center did not need to obtain a permit from City Hall. Because of special status as Port Authority of New York and New Jersey, they could make such choices outside the prevailing codes.”

This choice, he argued, allowed builders to use less steel in the columns presumably to save cost.

But by using high strength steel and thin cross sections, he pointed out, on impact the plane was able to cut through the outside steel bearing wall and enter the building--delivering thousands of gallons of jet fuel to the interior. During the ensuing fire, he said, the thin outside columns of the steel bearing walls were quite vulnerable to the rapid rise of temperature in them and reduction of their strength as a result of rising temperature of the steel.

http://www.designnews.com/article/CA6363426.html?industryid=43653

previously:

Forensic Expert Studying WTC Steel
(architecturalrecord.com- 01/10/02)
<snip
Last September, Astaneh-Asl was part of a team from the American Society of Civil Engineers that convinced the city of New York to delay recycling the WTC steel so that some of it could be studied for clues to the collapses. At a scrapyard in Jersey City he has helped identify the steel pieces to be saved.

The most important structural steel members to study are those severed by the planes and those that sustained the heaviest fire damage. The severed members will be studied to determine the speed and force of impact. Fire-damaged steel will be examined under an electron microscope for changes to its crystal structure; material scientists can then determine how long fires burned and at what temperature the steel failed.

Astaneh-Asl will also study structural members relatively unaffected by the crash or fires. “There were lots of different types of steel used in the towers—both high- and regular-strength—and we can learn things from pieces that fell hundreds of feet as the buildings collapsed,” he explains. Tests can measure the robustness of bolts and connections, for example, and identify the types of steel adequate for various structures.
http://www.construction.com/NewsCenter/Headlines/AR/20020110r.asp