modeling 2 towers on the same etabs model

[robertsaad6280]

dear all,
can i model 2 towers separated by an expansion joint above the ground floor level but the 2 basements level without jopint. i try to model but i found that the results are strange and espacially in dynamic analysis. what about scaling of results?
thankssssss

 

[structuresguy]

i have modeled completely separate objects simultaneously before, to test differing bracing configurations, etc. so it should be possible.

What is strange about the results?

 

[gyration]

As I understand, you want to evaluate each towers results seperately but they are combined at the basement levels, am I right?
After your dynamic analysis completed it is expected to get strange results because of your structural shape, in deed your mass source.
You must keep your stiffness matrix as if it is, but for each tower you turn on its mass and turn off the others mass.
Otherwise at each story level program will sum up all masses at that level and calculate mode shapes accordingly.