I have modeled two frames on SAP2000 and only different is the number of stories. First on is 3 stories and the second is 21 stories. Surprisingly, the drift of first model was 0.1m and for the 21 stories was 7.0m.
I checked many time to make sure everything else is same.
What went wrong?
Many thanks
Rakan
Please give a little more details about your model and analysis procedure. The drift of the 21-story frame is not rational. There is something wrong. How much is the time period of the frames?
Hi Rakan,
I agree with Fabian, you need to specify what type of analysis. If seismic time history or pushover analysis, it might cause that drift. It also depends on the ground motions you apply on your model. What kind of element did you use?
Please provide more details.
Cheers
Dear Rakan
It is the roof displacement that you are recording not the drift (Drift is dimensionless so 0.1 m doesn't make any seance). also, the response of the structure depends on the method of analysis, linear, nonlinear, static or dynamic. but assuming first mode deformation of the structure as the primary one, considering 3 m for each story which is a reasonable assumption and assuming plastic hinges take place at the end of all beams and none of the columns except the one at the base (Typical ideal mechanism for seismic performance of structures) the rotation of the plastic hinge (Plastic drift) of the base column will be 7/(3*21) -0.01= 0.13 which is a really large deformation!!! but first, please tell us what method of analysis you are using?
Good luck
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Waves