Smaller Concrete Columns

If you don't like the projections on the inside...put 'em on the outside..or vice versa...

Look upon them as a 'feature' or an oportunity...

Embrace their coulumnar characteristics...

be of the column Grasshopper...

Sure, but not always. I am using projections nicely in some locations, but some places (eg. where a row of columns with some staggered ones) it is a problem. If I can hide them, making them to six inches, that's all.

L shaped is a good solution to corner columns, as mentioned by some other viewer.

Thanks,

You could always consider a L shaped column. A 10" x 10" L has about the same area as a 9"x9". Or bevel the inside corner. Calculate or have it done fore you.

Dear Hendrik, It was me (ameega) raised the question as a guest. I need your help in this, pls.

Are you planning to build a single-storey or a 2-storey building?

There has been a very interesting thread about "bamboo" .If you use 2 or 3 bamboos lashed together and pour your conctete around them you will achieve far greater strenght than steel . Try a small test and go to destruction and you will have all the security you want or need.

Labor

Speaking of bamboos, I think I'm familiar with the grass. I grow up as a farm boy and had lived in a local bamboo house where the roof framing system are of bamboo materials. Our flooring are bamboo strips made from an "aged enough" bamboo poles wherein one of good quality should have aged at least 7 years. Some of this floor strips are still in good strength condition after more than 40 years.

Dear Willyap06, it's a two storey one.

If it's really important to hide the columns then you might need to work-out with bearing walls. Instead of supporting your second floor loads with concrete columns you can have the bearing walls do the supporting.

Concrete filled pipe columns , (Lalleys), might carry the same load at 6' dia.

"6' dia."

I believe this is a mistype. Pipe columns of that size is "huge" unless you are trying to use it as a support for a heavy structure...

Please clarify.

Presumably this structure has to meet some sort of building regulation approval?

I'd suggest looking at the regulations...

(PS the 6' must be a typo for 6"....it cant be 6mm 6cm 6m or anything else!)

You can use the wall as loadbearing, maybe even a concrete wall. 6" is a bit thin to obtain the cover to the reinforcement for a two layered reinforcement system and a one layered system may not give the strength required when considering buckling.

Another solution is to give up on a 3" strip and make the wall thicker. Generally you only see a wall from one side and so its thickness is not critical.

Steel windposts/columns can also be useful in these locations. A series of 5" x 5" posts can support the load better than concrete but the foundations are slightly different as is the need for beams to accomodate the transistion to whatever you have above. The reason for the slightly smaller dimension than the 6" is the additional requirement for fireproofing which takes up some thickness.

Friends--

If you go to ICF (Insulated Concrete Forms) for your walls, the required cover over the steel is reduced to 1" because the foam forms eliminate nearly all the drying of the concrete surface during the curing time. Therefore, two layers of reinforcement is easily encased with strength equivalent to a conventionally formed 8" thick concrete wall. They are included in the International Residential Code (IRC) for home construction of up to two stories over a basement, so engineering approvals are not needed as long as the design conforms to the tables and text in the IRC. This would eliminate the need for separate structural concrete columns.

Negative side: The cost of the wall increases by 10-25% over a conventionally built wall. The time to build will depend on the workers' experience. The thickness of the wall will be between 9.5 and 11.5 inches before application of interior or exterior finishes (the thickness depends on which form brand you use). Dimensions work best when put into multiples of 6" or 8" (depending on the form manufacturer's reinforcing web spacing), and almost always require a minimum spacing increment determined by the spacing of the forms' interlocking "bumps".

Positive side: In most climates, the effective insulation value of the wall is much more than the values from the standard heating and cooling people's heat loss tables (the tables are based on the assumption of light-weight construction). The wall is much stronger (can withstand 150-mph winds easily). The wall has a 4-hour fire rating. Sound transmission through the wall is much less. Mold and mildew growth are minimal, and the polystyrene does not provide food for boring insects such as termites or carpenter ants. Also, concrete can be poured in the winter without needing heat, extra insulation, calcium chloride additives, etc.

Neutral "side": Almost any house design that can be built with wall panels or stick framing can be built using ICF's.

Yeah, I've used them and I really like them. --John M.

You originally asked for a 9X9 collumn with a wall thickness of 6". The great think about cast in place concrete is you can make it any shape you want like a rectangel. I can design a collumn with a max width of 5.5" then you have space for sheetrock and all walls will be smooth. You can email me the loadings you have calculated, or I can assume the Massachusetts loads. I will design based on ACI (american concrete institute). I will send you all calculation then go get the design stamped, or I can stamp the plan for a negotiated amount if you live in Massachusetts. My email is NY_10@yahoo.com.

"I can design a column with a max width of 5.5""

What version of the ACI Code is your reference?