Q.: Why do we see so many cracks in flatwork around small columns?
A.: The problem seems epidemic in shopping centers. For example, this picture was taken in a shopping center where the quality of the concrete was generally good except at columns. Unfortunately, there were many columns.
There is an old, well-established rule that seems to be widely violated: Always isolate columns from the flatwork by means of joints. In your picture there should have been a joint close to the column and completely surrounding it. A common method is to wrap the base of the column with a strip of asphalt-impregnated fiber 1/4 inch thick and 4 or 6 inches high. Where the two ends meet it can be held in place by tape running circumferentially. But that is not all. There must be contraction joints running to the column. Difficulty often arises because the contraction joint pattern has been established without reference to the column location. Then, even if this pattern is later adjusted, the joints may not be located and installed in a way that makes them function properly. The contraction joint pattern should cause every column to fall symmetrically along the center line of a contraction joint. These contraction joints should be real working joints, not just dummy joints. This means they should be made 1/4 or 1/3 the thickness of the concrete.