Cost of Reinforced Concrete Columns 1

[asixth]

Hi guys,

I have a situation where some isolated 800 x 300 reinforced concrete columns (2.5' x 1') have been offset from the gridline. There are no architectural requirements to have these columns this dimension at this particular location, so I was wondering if it would be more economical to provide a 400 x 400 (1.25' x 1.25') square column in this location if it is easier to form and build and therefore, reduce cost.

What is the contibuting factor to the cost of reinforced concrete columns, should I call up all columns the same dimension for the re-use of forms or would reducing the material used be more economical?

 

[JAE]

One of the keys to economical columns is minimizing the complexity of the column ties. With a square column with only 4 vertical bars, you only need a "square" tie. If you have more bars in the column (such as 8) or if you use the rectangular 800 x 300 column, you would probably have more than 4 bars and need additional cross ties for the intermediate bars...which adds cost.

I think what you are hinting at is also true to an extent...that odd shaped rectangular column forms are more expensive than square column forms which many times are formed with standard form systems...but I think that some form systems are fairly versatile.

http://www.formtechinc.com/columnM.htm

http://www.symons.com/products/adjcolum.htm

And read from the bottom of page 9 on this link:

http://www.foxcor.com/images/EST_CONC1_paper.pdf

 

[hokie66]

JAE has a point with the ties, but with your example, I think the main difference in cost would be that the rectangular column is 50% bigger than the square one.