Expert: Veto Varma - 10/8/2007

Question
QUESTION: in designing a single storey  building at which points should the columns have to be rested?

ANSWER: Hi Ali,

In a single storey building, columns have to be rested on foundation. Foundation can be of any type e.g. spread footing, piles or thickened edge slab. Usually steel columns rest on steel plate on top of foundation. Concrete column uses dowels to connect to foundation.

Column are also laterally supported on top by joists or floor system or roof structure.

Keep in mind that if the height of column is more, check for slenderness ratio and it might need some lateral support in between also.

Hope this answers your question if not, do not hesitate to e-mail me.

Regards
Veto


---------- FOLLOW-UP ----------

QUESTION: how to design a foundation footing?

Answer
Hi Ali,

For foundation design you need to know the loading on the footing and soil conditions. Soil condition will give you bearing capacity of the soil and it will tell you whether it is fit for footing or not.

Once these things are known designing is very straight forward and any standard text book will give you detail. I will give you some preliminary idea about it.

Load divided by bearing capacity will give you the area of the footing where from you can find out width of the footing while actual load on the footing will help you determine the depth of the footing based on shear. if it is a reinforced concrete footing then based on moments you can find required steel area. Use the cantilever analogy to find the moments.

I hope this answers your question. Please feel free to e-mail me for your further inquiries.

Regards
Veto