The welds were not full pen... at least were the columns were made from 5- 6" plate...
Donald Friedman, one of the privately contracted engineers from LZA Technology (a division of the Thornton-Tomasetti Group) who helped oversee cleanup operations in consultation with the City of New York, provided a few notes on the column connections and how they appeared to have failed in his book After 9-11, An Engineer's Work at the World Trade Center:
What I never hear discussed is how the DNA of the structures... the structural design concepts of these buildlings determined how they would collapse based on where they were suffering damage
isn't that what you don't want to reveal to future terrorists? or am I misunderstanding your comment?
Jeffrey has clarified his intention and explained the relevant features of Tim Towers collapses.isn't that what you don't want to reveal to future terrorists?
Jeffrey misses the key feature of WTC 7 design that dominated the visual appearance of collapse. WTC 7 appeared very "CD Like" as the perimeter shell fell as a still intact entity after the core collapses inside the building. That was the consequence of the design having a very strong "moment frame" in the perimeter. In effect a reinforced belt around the perimeter holding it together.