Originally Posted by Bayner
Strange it sheared right there, and not at the bolt hole...
Not strange at all... The sharp corner on the bar is a giant stress concentration and a great place for a fatigue crack to start. While holes also exhibit these qualities they do much better than sharp corners. (Trust me, I studied fracture mechanics, the most common methods of introducing a crack into a sample coupon is to machine a 90 deg sharp corner into it)
Like John suggested a sleeve with new holes and removing that whole mid section crap should be strong enough to keep going.