concrete filled tube composite section

[dougantholz]

I have a canopy for a walkway that cantilever's up from a single column, up over the sidewalk. Because of the loads I cannot get a size the architect likes for the column. Does anyone know a way to bond concrete that is filled inside a tube in order to increase the bending moment capacity?

 

[mjohan]

You can go to

http://www.steeltubeinstitute.org/hsslit.htm

and click on the composite column load icon to get all HSS allowable loads for concrete filled columns.

 

[dougantholz]

mjohan,
I downloaded the design tables, and a few more. Thanks for the link. But at the top of each table states that the loads in the tables are CONCENTRIC. I have moment and axial load.

 

[mjohan]

I believe the tables will give you the values you will need to do a combined loading calculation on a column. They do not give you the E composite value but you can back that number out by solving for it using equations E2-1 or E2-2 in section 5-42, chapter E of the AISC manual. Then refer to chapter H to check for combined stresses.

Good Luck

 

[dougantholz]

mjohan, I have a question about strain combatability, crack control & bonding of the concrete to the tube in bending. Does anyone have any guidence?

 

[Ingenuity]

dougantholz,

There is a paper by Bradford in ACI Structural Journal #93/2 March /April 1996 pp 229-235 using strain compatability approach for axial and moment strength of short rectangular CFT's. It references a paper by Tomii et al in Japan Concrete Institute proceedings on bond issues.

Unfortunately, I do not have the Tomii paper so I cannot comment on what are significant bond issues.

HTH a little.