column shape comparison

[vavaving]

If two concrete columns were holding up a beam between them (that went through the concrete), how would the following two shapes compare, structurally?

Two 8-inch cylindrical columns

-vs-

Two 12-inch half-cylindrical columns with the flat sides facing one another

 

[kslee1000]

The first pir is easier to design by established method. Don't see any advantage in the 2nd pair (I would never use it unless for architectural reasons).

 

[RHTPE]

Why attempt to construct a column with a half circle cross-section (unless it's absolutely required by the architect)?

Just cuz concrete can assume any shape doesn't make it easy to construct. A column cross-section like that would prove to be much more expensive to form (there are no "standard" forms for that cross-section). And, whatever form the contractor dreams up is unlikely to produce reliable results.

Although I suppose you could use half of a steel or FRP circular column form combined with a sheet of plyform bolted to it. If the circular forms are readily available in your area.

Just my NTBH opinion.


Ralph
Structures Consulting

 

[vavaving]

I see, thank yous.

 

[dik]

Some jurisdictions have a minimum column size for concrete.

Dik

 

[Dinosaur]

The eight inch diameter circle has slightly less area, but probably has a higher moment of inertia on the weakest axis. Therefore, I can think of no reason to prefer the half circle cross section. As others have noted, forming the half circle will add cost to the half-circle columns. Good luck.

 

[rday]

What is this? A homework problem in a concrete class?

 

[vavaving]

Just a hypothetical question... it wasn't intended to be a logistical discussion, by the way. Thanks again!