Monday, November 9, 2009

Re: base plate design

Thanks. I'm looking for structural failures that were initiated at the base.
Overloaded tank sounds like a control or process failure and sure would have
been fun to watch from a distance. :)

The list has discussed hooked anchors pulling out of the concrete but ...
just discussions, no real forensic, analytical review information. I have
done remedial work on bases, usually because of something that occurred
after the design office. I have seen engineered details that I would
consider questionable but have no evidence that they are not sufficient
design. I have seen structural collapses which rotated the foundation out of
the ground on the end of a "pinned-base" column ... but not a wrinkle, crack
or stretch mark at the steel/concrete interface.

There are things that I know should occur for various types of base failure,
but I have never seen any in practice that could be attributed to design -
even multi-axial loading conditions.

The only thing that I have encountered (all too regularly), that I consider
a base failure, is cracked grout which is usually an engineered detail
failure. Apparently, nothing else seems to matter - or we just haven't
stretched that envelope far enough, yet.

Paul Ransom, P.Eng.
ph 905 639-9628
fax 905 639-3866

> From: Harold Sprague <>

> Yes. I have known of several failures for tank anchor rods. The anchor rods
> stretch a long way. This most commonly occurs when tanks are overpressurized.
> Regards Harold Sprague

>> I'll repeat a question that I asked a while back: Has anybody ever known a
>> structure failure due to base (steel/concrete) or anchor failure in the
>> finished state (not during construction)? I have heard anecdotal stories but
>> nothing confirmed as engineering failure vs overload material or
>> construction failures.

>> Paul Ransom=2C P.Eng.

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