Double column design 1

[azh]

I have a circular 600 mm diameter column which may need to be halved to accommodate an expansion joint.Obviously the column will become a semi-circular column and may become slender( am i right). Which book is the best to refer to.Can anyone help ? How would I design the foundation/pilecap?

 

[JAE]

You are right that the column is now two, semi-circular shapes taking less load than the singular column would have. The design would proceed according to the code you are under. For irregular shapes, the development of an appropriate interaction curve is difficult. We would normally rely on the PCACOL and IRRCOL programs written by the Portland Cement Association (in the U.S.).

For the caps, normally you don't see the expansion joint taken through the cap. Simply tie the columns into a common concrete cap as you normally would.

 

[phuduhudu]

If you want to halve the column JAE's advice sounds good but the question is can you not move the joint to one or other side of the column? A MJ through the middle of a circular column sounds a bit of an odd solution. Otherwise how about having two smaller rectangular columns side by side? It will be worth goign through all the visual implications with the architect. Carl Bauer

http://www.bauerconsultbotswana.com

 

[azh]

Thanks JAE and Carbauer. The architect may not be in favour of having two smaller rectangular columns side by side.When u say "move the joint to one or other side of the column", do u mean do not split the column and put the joint somewhere between beams/slabs instead and design these elements as cantilever ?

 

[dik]

Moving the joint, if you have a spandrel beam, likely means using a corbel and teflon bearing to support the spandrel beam on the column and designing the column for whatever moment is generated by eccentricity.