wrote:
In uk.d-i-y, Tony Bryer wrote:

My memory on the details is a bit hazy but there was a loss-of-life

disaster at a disco/club in the USA (Kansas?) where the designer
had
supported walkways at different levels on threaded rods from the
ceiling. The design was fine, but to make erection easier the
contractor changed the one rod with nuts at each level to a series
of shorter rods offset at each level, failing to appreciate that
this left the topmost nut carrying all the loads from below, not
just the one level.

Your memory is pretty accurate: it was the Hyatt Kansas City. One
decent summary is at

http://www.glendale-h.schools.nsw.ed...Hyatt_page.htm

As that page hints at, the difference between design and
implementation
wasn't just silliness on the builder's part: the original design was,
if
not unimplementable, certainly a royal PITA: the uniform-diameter
suspension
rod would've needed threading for most of its length, so as to be
able to
spin the nuts up from 2nd-floor-level to 4th-floor...

(Analogies to software development - "the bug is in the spec", "no it
isn't, it's the way you coded it, and I'm an Analyst-Architect and I
get
paid more so I must be right" are of course entirely spurious ;-)

Stefek

Thats some nut spinning!

Builders must not change structural elements without seeking approval,
for exactly this reason.


NT