Yielding Mechanism for Ordinary Reinforced Shear Wall 1

[btseng]

Hi all,

This question jumps out when I was reading details about the special reinforced shear wall, which already has been developed tons of requirements in ACI 318.

My understanding is that ORSW also has a yielding mechanism since it has a relatively moderate R factor, 5 (if combined with special RC moment frame effectively can go up to 6!), and there's no height limit for structures specified as SDC C. Though the earthquake is moderate, it can still develop some sort of energy-absorbing behavior. I didn't find too many materials talking about seismic requirements for ORSW, any ideas or recommendations?

Cheers!

 

[KootK]

I've long had the same question. Is there base hinge? Or are we just relying on the general energy dissipation of the entire setup, maybe including non-structural stuff?

I asked this very question of James O'Malley during and NCSEA seismic seminar and didn't really get much of a response I'm afraid. The gods of seismic seem to be gods of high seismic only it seems.

Without being able to substantiate my opinion, my opinion is this:

1) There is still plasticity anticipated at the same locations for which it is anticipated in the higher ductility systems.

2) What there is not is any rigorous attempt at capacity designing the neighboring stuff.

 

[btseng]

Thanks for your response Kootk!

I checked several project drawings in which the shear walls are designed as ordinary reinforced shear walls and specified as SDC C. Clearly in both cases the boundary elements are not designed following the code requirements - I guess there are no specific clauses about ORSW boundary elements in the code, the design is totally up to the engineers. The yielding mechanism for ORSW is a sort of "conceptual design".