test your brain

[mikeyniney]

Are plastic hinges designed in columns, in girders or in both?

Which is more likely to have a smaller natural frequ of vibration, a steel moment-resisting frame or a concrete moment resisting frame, given equal heights and moment of interia?

Which is more likely to have a larger damping ratio, a steel or concrete moment resisting frame?

 

[dik]

First kick at the cat...

A collapse mechanism can have hinges in both columns and girders at different nodes.

The concrete will have a lower frequency due to the reduced Modulus of Elasticity as well as the internal damping.

The concrete frame due to cracking will have a greater internal damping.

I'll let Ron correct these <G>...

 

[JWB46]

I think dik's kick at the cat was pretty well spot on target. (But note that the concrete frame will probably have higher mass and this obviously affects frequency, damping etc.) Were they trick questions or something?

 

[dik]

I could clarify the hinge issue a bit... but, we'll wait...

Regarding the increased mass... might just slow it down a tad...

 

[Ron]

Huh? Whut he sed!

dik is on target as usual.

His priorities are correct as well....always kick at the cat first.