Horizontal Beams showing zero axial force when they should have non-zero value on application of lateral force on 2D Frame

Question:

I am modelling simple 2D frames for the purpose of analysing their structural response from Unit Lateral Load loads applied at the top of Frame. I have kept all connections as pinned to compare the interal forces with those from hand calculations. However, the horizontal members which have been modelled as beams in the frame are showing zero axial force (Fx) when there should be non-zero axial forces in the beams. Why is this so?
All members have been modelled as Beam elements

Answer:

Hi,

The zero axial forces in the horizontal members are caused by the story diaphragm. If you change it from 'Consider' to 'Do not consider', you can see non-zero axial forces. 

Regards,
DK Lee
Creation date: 8/2/2018 12:16 PM (dklee@midasit.com)      Updated: 8/2/2018 9:47 PM (dklee@midasit.com)
Files   
Axial Force.PNG
resend
Axial Force[1].PNG
resend
DataImage2.png
resend
DataImage27.png
resend
DataImage71.png
resend
DataImage76.png
resend
Leadenhall South Frame Original (On Site Sections) RIGID Connections.mgb
resend
Leadenhall South Frame Original (On Site Sections).mgb
resend
Model.PNG
resend