Stiff but flexible

If you're talking about elastomers then...(for example)...

Elastomers are flexible under shear and uniaxial deformation, but they are very stiff against volume changes. This feature makes the design of a bearing that is stiff in compression but flexible in shear possible. Under uniaxial compression, the flexible elastomer would shorten significantly and, to maintain constant volume, sustain large increases in its plan dimension, but the stiff steel layers of the steel reinforced elastomeric bearings restrain the lateral expansion.

I don't know exactly how this would translate for the "steel" predicament you are in...

#29 -- I agree.

Interesting what people pick up in different text. I would have simply assumed that the metal bars allowed some room for slight movement such as through subsidence, earthquakes (ok perhaps not in this example) or simply even wind factors.

It may not be quite logical - and by the sounds of it not even correct - but coming from a place which is both incredibly windy and prone to earthquakes I would have put my own interpretation and simply assumed some minimal movement was allowed without compromising the integrity of the structure.

So to me, stiff doesn't exclude flexible. Or vice versa.

From the point of view of a yoga instructor, "stiff but flexible" isn't possible- one does exclude the other. It might sound okay to some people for a steel skeleton, but it doesn't apply to the human skeleton- if your lower back or hamstrings are stiff, they can't also be flexible. "Strong but flexible" would have been much better.

#22 -- Also for expansion and contraction due to heat and cold. I think that must be substantial in the case of the metal shell of the Statue of Liberty. And the more I think of it, the more Eiffel's engineering amazes me.

There can be and have been earthquakes in the NY city area. Not major. Knock on wood.

I think #20 gives support to Tony's side. In the areas where elastomers are stiff, they aren't flexible, and vice versa. You couldn't say that they are stiff and flexible under shear and uniaxial deformation, but neither stiff nor dlexible against volume changes.

It's clearly an stupid-cow thing but it gets the idea across.