Story Drift Results do not Match Joint Deflections
Story Drift Results do not Match Joint Deflections
(OP)
Could there be any reason that the story drift results would not match joint deflections? I have a case where I define a node as a story, and compare the story drift results to the same node joint deflections. The story drift does not contain a Y-drift (Y is vertical), but the joint deflections do contain Y deflections. Any ideas? I attached a screen shot for reference.





RE: Story Drift Results do not Match Joint Deflections
RE: Story Drift Results do not Match Joint Deflections
RE: Story Drift Results do not Match Joint Deflections
There is no Y direction drift because Y is your vertical axis. But, you are getting X and Z direction drift, right? And, the X and Z direction drift does match your X and Z joint deflections.
RE: Story Drift Results do not Match Joint Deflections
RE: Story Drift Results do not Match Joint Deflections
Also, what version of the program are you running? There may be an old bug that I don't remember. If I know the version I could look at the release notes for subsequent releases to see if there was anything corrected that sounds similar to what you're seeing.
RE: Story Drift Results do not Match Joint Deflections
RE: Story Drift Results do not Match Joint Deflections
Story 1 is at a 0 ft elevation. Since there is no Story 0 defined, story 0 will be assumed to also be at a 0 ft elevation! And, story drift calculations blow up (divide by zero errors). Hence the program refuses to do the calculation.
Try instead to define joint N12 (which is at -5 ft elevation) as your story 0. Then you should start to get drift results.
Apparently I was wrong about the Y drift not being reported when the Y axis is vertical. It will still be reported based on the "height" difference in the Z direction. Though I would not personally use this for anything as it is not a true drift.
RE: Story Drift Results do not Match Joint Deflections