Tony wrote:
jeff_wisnia wrote:
A more complete set of photos of this June's Shanghai building
collapse and diagrams explaining what happened and why.

http://home.comcast.net/~jwisnia18/bldg_fall/

I'm glad I don't live there, I'd never remember which apartment is mine,
they all look alike, even the ones that are different look very similar.
Well if the flat one was my building I suppose I could pick it out of
the rest.

What is with the hollow pilings? They really look weak with a little
bit of steel wire mesh in them. Hollow? Would it have happened if it
were steel I beams encased in concrete?

I'd guess they were a contractor cutting corners if I had to guess...if
those hollow ones were really actual pilings and not drain conduits or
somesuch. There also appear solid pourings as well. W/O design
documents are to say what might have been intended.

Certainly the lack of any steel of consequence meant there was
absolutely no tensile strength in the design to speak of.

Looks to me like what happened was that the lateral force from the
loading and wet soil conditions caused the whole thing to tilt and at
the critical point the tension load was too much and they fractured.

As to the question regarding steel, undoubtedly would not have broken
cleanly; what would have been total result would have depended on depth
of pilings (moment arm to resist rotation) and actual soil conditions
and, of course, whether any steel was of sufficient size/strength to
withstand the moment arm itself of the load caused by the initial tilt.

One would wonder about the long-term stability of the rest against
extraordinary high wind, particularly if the supposition there might be
inferior work as compared to design in play were to be true...

It really is hard to fathom there would be no steel reinforcement in the
design...

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