[TheForge] thermal expansion in extremely heat

[Bruce Freeman]

The roadway buckled because of insufficient expansion joints.  A
roadway is a linear structure and expands in all directions, including
against its length.  If it gets too long for the allotted space, it
buckles.

If the metalwork is one metal, one piece (e.g., a weldment),
unconstrained in any way, then it will expand uniformly and without
undue stress.  Mixing metals or constraining expansion could lead to
problems.  A railing could be analogous to a roadway, and buckle if no
provision were made for it.  The provision need not be obvious.  A
bend in the railing can take up a lot of expansion.  Hence, you won't
see too many railings buckled in the middle.

As to warning tags:  I recently bought a couple hand saws I've
discussed elsewhere.  The instructions for these warned I should wear
eye protection (which is reasonable) and HEARING protection!  I can
just see myself wearing hearing protection while cutting the upper
limb of a tree.  I would miss hearing the gentle cracking as the limb
started to fall and get clobbered when it landed on my head.  Then
again, maybe they also suggested I wear a hard hat!

On Thu, Jun 25, 2009 at 2:29 AM, terry l. ridder<terrylr at blauedonau.com> wrote:
> hello;
>
> with the current heat wave in northern illinois i was impressed by a
> news story about illinois route 59 buckling from the heat. the video was
> impressive to see a three ft piece of rather thick concrete shattered by
> the thermal expansion of the roadway.
>
> i have never taking thermal expansion into account in any outside
> metalwork and now i am wonder if i should have. i was assuming that the
> entire piece would expand more or less equally across the whole piece.
>
> then it occurred to me that metalwork outside in the summer presents an
> object that could burn the unsuspecting person. i mean i know better
> than to crap a piece of metal that has been baking out in the sun for
> most of the afternoon. given the stupidity of many of citizens of
> chicago and the state of illinois evidence by their continuing to vote
> in corrupt politicians, these people would be the ones to get burned.
>
> do outside metal sculptures have warning on them warning of the
> potential to be burned?
>
> --
> terry l. ridder ><>
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-- 
Bruce
NJ

The total lack of evidence is the surest sign that the conspiracy is working.