Hi,
I have a question regarding column deflection and sway in STAAD. The below picture shows the deformed shape of a column subjected to lateral forces in a frame. I know the maximum sway/drift in STAAD is gotten from the node displacement value (translation) at the top node in any direction needed (please correct me if I'm wrong) but my confusion is in obtaining the deflection value of the column member itself.
I have used the DFF parameter for deflection check and have set the DJ1 and DJ2 parameters to the top node and bottom nodes.
I'd like to know if the deflection value given by STAAD design output considers or includes the lateral translation of the top node or is it based on the assumption that the top and bottom nodes did not move (similar to beam bending). What is the best value to use for the column deflection? The STAAD output value or the nodal displacement close to the middle of the column?
Thanks.
Deflection check using DFF, DJ1 and DJ2 is for the horizontal members only. It is not recommended for vertical members. For vertical members you need to check the deflection manually with the help of displacement values.
To know more about how deflection is calculated refer help file.
file:///C:/Program%20Files/Bentley/Engineering/STAAD.Pro%20CONNECT%20Edition/Help/GUID-A01D284B-0114-4F2E-852F-1856C7F8C44E.html
Thanks for the clarification