Dear Benny,
I checked your Sap2000 model and found that you doubled the FloorLL on all beams. You first gave distributed frame loads to the frames and in addition the same load is coming from area elements with "Uniform area load". This is why you are reading doubled results. So there seems no bug on this subject.
Etabs is reducing the load because it considers the intersection between beam-floor and removes this intersection area from floor. This is why the loads are a little bit reduced in Etabs.
But I also want to comment on your loadings. You made a PDELTA (nonlinear case) analysis and then started all other load cases from the stiffness of this PDELTA analysis results. But:
1) If you will combine these load cases, this will result in extra deflection readings from normal because Sap2000 will add the deflection from PDELTA (caused by DL) for all load cases in that combination.
2) There is no need to do that for vertical load cases like FloorLL since no effect (neglectible) on moment results (but effects deflections of course). You should do that for vertical loads like EQX and EQY loads (or wind) that will not be used in the same combination. But in some seismic codes they are combined together so you should be careful again.
I hope this helps.
Regards.
I checked your Sap2000 model and found that you doubled the FloorLL on all beams. You first gave distributed frame loads to the frames and in addition the same load is coming from area elements with "Uniform area load". This is why you are reading doubled results. So there seems no bug on this subject.
Etabs is reducing the load because it considers the intersection between beam-floor and removes this intersection area from floor. This is why the loads are a little bit reduced in Etabs.
But I also want to comment on your loadings. You made a PDELTA (nonlinear case) analysis and then started all other load cases from the stiffness of this PDELTA analysis results. But:
1) If you will combine these load cases, this will result in extra deflection readings from normal because Sap2000 will add the deflection from PDELTA (caused by DL) for all load cases in that combination.
2) There is no need to do that for vertical load cases like FloorLL since no effect (neglectible) on moment results (but effects deflections of course). You should do that for vertical loads like EQX and EQY loads (or wind) that will not be used in the same combination. But in some seismic codes they are combined together so you should be careful again.
I hope this helps.
Regards.
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