Shear at Top of Column

[PEinVA]

I have a column 2'6" above a slab that is framed into a steel roof system. The roof system comes in on an angle and creates a kicking force through the column. In some cases this column has split and cracked and we need to repair them. They have been scanned and do not have ties. However in designing a fix, can I account for any help from the concrete with respect to resisting the kicking force?
What do you think?

RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke

http://www.tbastructures.com

 

[hokie66]

RC,

Looks like you are having another bite of the cherry after your previous post. Since your column has cracked and it has no ties, I would say it is useless. I think it broke because it was so short, thus stiff. Thermal forces in the steel structure snapped the stub column.

I am assuming this is some sort of diagonal cracking. If so, without ties, the column has no residual shear capacity to resist horizontal load at top of column. Perhaps it can resist some load at slab level. Three possible solutions: 1) if resistance at slab level can be relied on, wrap columns as suggested by others; 2) chip out column and recast concrete stub column designed to resist all forces, including thermal. Check that roof structure can resist these forces; 3) chip out column and replace with steel column. The third would be my preferred option.