HIGH DISPLACEMENT IN ETABS

[RohanDutt]

Hello Everyone,
I have made a two-story ETABS model (client's request) and unfortunately I am getting a insanely high displacement, Uz in the joints.
I used to work on ETABS 2 years ago and have completed many projects. But I guess I have forgotten some key step. I have yet to adjust the modifiers and everything but it shouldn't be having such high displacement in the first place.Would be highly obliged if anyone can take a look.

 

[wannabeSE]

Does the analysis log have any warnings? I did not look at your model (I don't do Eng-Tips at work, and I don't have ETABS at home) I have seen a girder deflect 50 miles in ETABS when the top of the columns are pinned and the girders framing into them are pinned. I was surprised ETABS would run, other software won't with similar releases.

 

[RohanDutt]

No warnings. No mm to meter mistakes. No kilonewton to newton mistakes. Have gone through each and every material, frames, walls. Do not seem to understand what the problem can be. The loads are correct and the points at the base are assigned as fixed.

 

[BOCH]

I couldn't open your model, something is wrong in the file.
Have you checked in the analysis log file that nothing is un-stable and the model is not ill-conditioned ?
There might be at some places two overlapping joints, one of them is connected to the surrounding shell elements and frame elements and the other is not. This joint will present a very high Uz displacement.

 

[Roy88]

Hi RohanDutt,

I have opened your model. Run a modal analysis with vertical mass turned on and you will see where the huge instabilities come from. Your upper floors seems to be 150 mm thk. timber floor without any beams. Are you sure it is going to take ur 1.5 kPA SDL and 2kPA Live Load?