Compressive Strength Capacity of Composite Members?

[Dlmyln]

Good afternoon. I am designing a structure using composite members (HSS Tubes filled with concrete) using ETABS software.

The latest version of ETABS lets you design these members without problems. What I am confused about is that when I use the same member (HSS 8x4x16ga. filled with 3000 psi concrete) as a column and as a beam the compressive capacity greatly changes. All the other capacities (shear & moment) stay the same.

Why is this happening? Is there a reduction factor applied?

 

[Celt83]

Review the unbraced lengths.

Lucolumn = 96
Lubeam = 528

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Mjkkb2]

I see one issue
One member is 8 ft long vs the other 44 ft long. It's no revelation the capacity as a compression member will be different due to KL/r.