[SML] Question about Safe Working Loads

[Bill Conner]

> Structural design standards use much lower safety factors (and the
> correct term is "safety factor" in that context, "design factor" is
> not a common term in structural engineering), because an I-Beam is a
> big hunk of steel that doesn't vary a lot- in general nothing's going
> to happen to your I-Beam that unexpectedly weakens it without being
> obvious.

The safety factor is the actual load  to the ultimate breaking
strength.  The design factor is what is required.  If I design a to
have a design factor of 1:8, a contractor may use 1/4 wire rope rated
at 7000 for a load of 500, but that is a safety factor 1:14.  So, the
design load is what is required, and the safety factor is what the
actual ratio is. I think E1.4 has his right.

Otherwise I believe we agree that it's hard or impossible to find one
safety factor or require a single design factor for everything,
because of what forces and other actions on the piece are likely or
possible.


-- 
Bill Conner FASTC