I have been watching this thread trying to keep out of it but I lost the
struggle .....

Michael Daly wrote:
snip

For the design load - yes. For the actual load - no. See my other post.
The issue is whether you get warning of impending failure. Overdesign
can result in brittle failure without warning.


Wouldn't the supports be overdesigned as well?
I don't recall seeing anything that said that oversizing one component
in a system will/could/might cause a failure at the "design" loads.
Very obviously the entire system does need to be considered _if_ loading
is going beyond the design on any given component.

What I am seeing is a debate that a single (or multiple) over designed
component in a system can cause a failure else where in the system but
losing sight of "designed" and as has been said several times this is
untrue _if_ we are still talking at _designed_ loads.

By the virtue than one constructs a beam capable of carrying double the
designed load by no means ensures that the rest of the system, posts,
footings, etc, are capable of carrying this. But also this same
oversided beam at the _designed_ loads will not cause catastrophic
failure in any other components unless they were themselves either under
designed or inadequately constructed or had a load increase beyond design.

If one constructs a structure like a beam that is, for e.g. capable of
carrying 50% more loading than design but the posts used are still at
designed specs loads, then for sure, if you load the beam to its
increased capacity the posts and other parts are liable to fail.

This is almost an urban legend type of issue. The real item is that all
parts of a structure need to be designed and constructed to meet the
needs and loading requirements. Over sized/designed construction of one
part will not increase the capacity of the system and is where people
become misdirected like some of this discussion. The failure is always
due to trying to load at a level to the specs of the over built piece
rather than the original design. ... and thus results in these
misconceptions that over designed beams, as in the examples in this
thread, cause failures in the posts and where in reality the posts were
never designed or capable of carrying these loads.


The case from which this derived is one where someone is considering
a single element, not designing the whole building. If someone in
a forum like this who is not an engineer or architect gets hold of
a ridiculous claim like "overdesign is never bad" all sorts of
unexpected evil can result.


Perhaps you can quote the regulation that states this?


Criminal Code in Canada.
Sorry this doesn't match in my mind.
Yes, it is criminal to construct an occupancy build that does not
conform to minimal standards stated in various regulations and as result
incur a failure causing 3rd party losses in property, life, well-being,
etc. There is absolutely nothing I have seen that says I can not exceed
any building construction standards and requirements.

Ed