[slipframe]

If the Hyatt walkway had been built as it was designed, I'm sure it would have worked fine. But was it realistic to build it as designed? The design called for something like 12 meters (12m is my estimate from it needing to span the 2nd to 4th floor) of continuously threaded rod. Is cutting 12 meters of continuous thread on one rod a realistic design? This is a real question, I don't know the answer but this seems suspect to me. Wikipedia says the reason the construction company changed the design is because they would have to screw the bolts past several meters of thread per rod and they thought such long sections of threading would be subject to damage during construction.

Obviously their "solution" was lethal. But the original presumably safe design seems impractical at best.

[nemetroid]

The original design was bad in several ways.

> Analysis of these two details revealed that the original design of the rod hanger connection would have supported 90 kN, only 60% of the 151 kN required by the Kansas City building code. Even if the details had not been modified the rod hanger connection would have violated building standards. As-built, however, the connection only supported 30% of the minimum load which explains why the walkways collapsed well below maximum load (Feld and Carper, 1997).

(my emphasis)

http://anengineersaspect.blogspot.com/2009/07/the-28th-anniv...

[slipframe]

Excellent information, I never heard this before. Thank you.

[mikewarot]

It is possible to cut a single thread 12 meters long, but it would be hard to position on the construction site.

I worked in a gear shop for 5 years, yes, threads that long can be done. I suspect it might have been cheaper to get a rolled thread in that length, rather than a cut thread. Rolled thread is likely to be stronger, as it is formed, and not cut.

[himinlomax]

Screw threads are incredibly strong. From memory, small (M3) standard screws with common materials are rated for several kN of load.