Shielding effect of one column on another for in plane wind calcul.

[CHARLESCOSTA]

There are 3 columns in a plane braced frame spaced at 6 m. In order to calculate the total wind force on frame when wind is in the plane of frame,I get the force coefficient for single column(I section) as 2 . This multiplied by depth of column(500)*height(16m)give me the total force on a single column.For total force on frame do I multiply this value by 3 or will there be some shielding effect of upstream columns on second and third columns

 

[Dinosaur]

Lots of folks think that there is. Maybe. But what if the wind shifts 5 degrees?

 

[apsix]

AS/NZS1170.2 (Australian/New Zealand) stipulates that there is no shielding if the (member spacing/projected width) ratio is greater than 8.
For ratios up to 4 there is a shielding factor of 0.2, interpolate between.

Dinosaur also raises a valid point.

 

[CHARLESCOSTA]

Thanks apsix for giving requirements of AScode.This information was not available with my code(IS)to the best of my knowledge.Its because of the same reasoning as
given by Dinosaur that I have never considered shielding in such cases.Confirmation from both of you have definitely
given me confidence.

 

[haynewp]

I don't include shielding.