When people are repairing a structure, but the rate of damage is outweighing the contribution you would have by repairing, I noticed a suicide charge works very well to distract. Examples would be using a chem trooper against camping MRLS on top of White Out, or Med tanks in the tunnel of Canyon attacking refinery. Using a buggy/humvee works too.
Often times when I tried this, the building was able to be fully repaired when all the arties/meds were focused on me.