Drift Capacities in ASCE 41

[JIMEY]

I was told by someone that it is important to consider drift capacities when doing a seismic evaluation. Particularly for things like unreinforced masonry and stuff like that. As they explained it to me, if you have something like a masonry wall which is not being used as part of the seismic force resisting system, it still has to be able to move along with the building without failing - even if it is just going along for the ride. Makes sense to me. They told me to look in ASCE 41 for drift limits for different materials. I'm reading through it right now, and I can't find anywhere that even mentions drift capacity. Can someone please tell me if it is actually in there somewhere. In particular, I am looking for masonry walls. Thanks a lot.

 

[SRIVINAY]

I am also going through masonry structures. i came across this course it might help you
Link

 

[JAE]

I believe that component actions in ASCE 41 are classified as force-controlled or deformation-controlled depending on the post-elastic behavior of the component.
For walls "going along for the ride", or "deformation controlled" you'd probably have to take the actual seismic drift derived from ASCE 41 methods and apply that drift to the wall and see how it responds.
So not termed "drift capacity" but perhaps "deformation controlled" in 41?

 

[M.Honda]

To this end, can someone elaborate more please about the so called "deformation-controlled" and "force-controlled" actions?
As I understood from ASCE41, deformation-controlled actions refer more to actions causing ductile failure (exceeding yield value of the member considered), so basically we load the structure and monitor the deformation until the structure fails. Whereas the force-controlled refers to actions causing brittle failure (before reaching yield point), that it pertinent to loading the structure and keep the force monitored until the structure fails in a brittle manner.
I am not so sure If I did understand it correctly.

If you do not see it, you cannot design it!

 

[StLHokie]

Late to the party, but ASCE 41 focuses on performance based design as opposed to strength/force based design. Performance based design is a different design methodology than your typical strength-based design in that rather that designing elements to resist loads, you are designing elements achieve certain deformation characteristics through elastic and plastic behavior. A strength or force based design qualifies building elements based on their ability to carry a maximum load. Performance based criteria qualifies building elements based on their ability to deform and deflect. You essentially design to allow for certain amounts of ductility.

There is a youtube series by Dr. Graham Powell & CSI that discusses performance based design in depth, and it's extremely helpful in explaining the intricacies of performance based design and the requirements. [URL unfurl="true"]https://www.youtube.com/watch?v=HpnICZuoQdU[/url]