Ruchadaphon
Civil/Environmental
- Feb 7, 2024
- 2
I have been working on a project to investigate how ETABS version 21.0.0 captures frame and shell elements in vertical structures (columns) differently.
Details on the testing are that all of the column height is 4.2 m. all subject to the same building, all same material(concrete fc'50MPa), and it is nonsway column.
Now, This is the graph comparing Mu2 (Design moment)(weak axis) to the depth of the column(width 400,500,600 mm) for the frame and shell element.
As you can see, with a width of 500 mm the Mu2 of Frame starts to use Nonsway Moment(smaller value) alternating with Minimum Moment(Greater value).
My questions are:
1) which criteria ETABS use to design which moment will be used for the designation? (minimum moment from eccentricity or Nonsway moment)
2)According to the ACI318-19 standard, It stated that "It is not intended that the minimum eccentricity be applied about both axes simultaneously".Does it mean that either axis 2 or axis 3 will not use moments from eccentricity at the same time?
Thank you very much.
Details on the testing are that all of the column height is 4.2 m. all subject to the same building, all same material(concrete fc'50MPa), and it is nonsway column.
Now, This is the graph comparing Mu2 (Design moment)(weak axis) to the depth of the column(width 400,500,600 mm) for the frame and shell element.
As you can see, with a width of 500 mm the Mu2 of Frame starts to use Nonsway Moment(smaller value) alternating with Minimum Moment(Greater value).
My questions are:
1) which criteria ETABS use to design which moment will be used for the designation? (minimum moment from eccentricity or Nonsway moment)
2)According to the ACI318-19 standard, It stated that "It is not intended that the minimum eccentricity be applied about both axes simultaneously".Does it mean that either axis 2 or axis 3 will not use moments from eccentricity at the same time?
Thank you very much.