Steel jacketing for concrete column

[engOFFG]

Hello

I have two-story old existing building, core tests of some columns show that concrete of some columns are failed , concrete strength is 50% less than design strength
we are are in stage of using steel jacketing ( plates & angles) to strengthen these rectangular columns
please I need to know how to calculate this jacketing components as per ACI , and which ACI code I can use
and if there are there different ideas for steel jacketing
in case of columns at expansion joint where 1 or 2 sides of column are not accessible to put plates , what would be the solution?

Thanks

 

[RPMG]

The most common fix is to place new rebars and concrete around the existing column per ACI. If you're using steel, the design should be by AISC.

 

[engOFFG]

Thanks RPMG