Question - Shear Wall Behavior

Hi,

I just model a 2D Shear Wall Lateral System using Member Type "Wall". The vibration shapes modes seems to be correct, but the period associated with this modes are very large. Maybe this type of member is not correct for modeling this type of lateral system. I saw the example posted about Cantiliver Wall, but it seems to simple and I want to do a more reliable analysis.

What I did is to model the lateral system wall as a member type "wall", as I have 2 walls in my model. I used a constraint in every node of each floor in x direction in order to model the rigid diaphragm, and use a "lean column" to capture the effects of the interior columns.

One thing I notice is that my "wall" members at the base has only 1 restrained point a the center (as I wanted fixed at the base) insted of having a linear restriction per wall lenght.

Thanks.

mm.. I cannot say much on that type of element because I have never used it.
However it always seemed to me that the "wall type element" is a quite basic fiber element type with all the pros and cons of a fiber element analysis. I guess that first you have to be sure you really need a fiber element analysis... What do you want to capture with this element that cannot be captured with a Giberson beam element? neutral axis movement? evolution of cracking? better representation of M-N interaction? etc.? If none of those will have a large effect on your results, then don't throw away the giberson type element just because "it seems too simple". In this situations I always like to quote Einstein (sorry for bringing up such a big name that really seems out of place in here) that once said something like "things should be made as simple as possible, but not simpler". I believe it applies to seismic analysis as well.

But, if you actually need a more advanced analysis, try out the wall type element and let us know if it works and if it is a feasable analysis in Ruaumoko, we will all be interested in that. If you keep struggling with Ruau and the wall type element, than try opensees or seismostruct, which are two very well know fiber element seismic analysis softwares, and probably more suited than Ruau for the fiber-based stuff.

Cheers,