Structural steel/concrete column

[woodman1967]

I did a design and spec'd a square HSS 10" column. Anyway, the architect doesn't want such a large column since they still have to fire treat it.

Their request was to design a column of steel encased in concrete.

I've done columns of just steel and columns of steel hollow sections filled with concrete but not like this.

Is there anything I should keep in mind? Should I change the hollow section to a W shape?

Any advice would be appreciated.

 

[JAE]

AISC 13th Edition has tables for composite steel-concrete columns - you could start there.

 

[csd72]

The steel encased with concrete would be larger by a long mile.

Why cant they coat it in intumescant paint - this can give up to 2 hours fire rating in the thickness of a few coats of paint.

 

[kslee1000]

What is the controlling factor on the 10" HSS column? Is it filled or hollow?

 

[vandede427]

I agree, encasing a steel column in concrete is probably going to make your column the same if not bigger than the 10x10 tube.

The problem of fire-treatment and column size AFTER the design was put out seems like a break-down in coordination by the Arch.

Can you make a thicker 8x8 work?

 

[woodman1967]

Thanks everyone for your help

The project requirements have changed and they are now specifying concrete posts and lintels.

So back to the drawing board

 

[kslee1000]

Concrete column would be much larger than 10" HSS. But better in fire rating I guess.

 

[csd72]

Check the minimum column dimensions for the fire rating in the code, check that the concrete can take the axial load as if it was a plain section - thn there is your initial concrete column size for the architect to compare.