Your comment, "...wondering if the bracket will be as strong as original after I hammer it....", prompts me to think that you haven't been using them properly, and this caused yours to bend (and I'll bet that the long bolt is also bent).

The brackets are not meant to maintain belt tension indefinitely (key words being "not" and "maintain") -- they are for adjustment purposes only. By its mild steel makeup, it was never meant to hold the belt's tension for long periods, but only intended as a convenience to get the alternator rotated to the correct belt tension.

What I mean is that, in the old days (before these brackets), you had to use some pry bar or large screwdriver to pull/push on the alternator (or P/S pump) to achieve the correct belt tension, and then tighten the nut or bolt to hold the unit there. Not only were your two hands busy (and you could have used a third hand), but that pry bar would usually twist the alternator or pump casing so that the belt wasn't correctly tensioned.

Then this adjustment bracket was introduced, and you could adjust the tension on the belt by simply turning a small bolt, and it would tighten the belt without twisting the alternator on its mounts! However, you're not supposed to leave the bracket's bolt in that position. After tightening the larger adjusting nut actually meant to hold the alternator (or P/S pump) in place with the correct belt tension, you're supposed to slack off on the small, long bolt on the adjusting bracket to relieve the tension on the bracket. I usually back the bolt off about three or four turns, so it lies loose -- saving it for the next time that I change the belts and need it. Not only does this prevent the bracket from bending, but it will also save that long bolt from bending and its threads from being stripped, which is also a common result of misuse.