What's the magnitude and direction of the load? I've had a 2" thick piece of timber sat on a concrete floor for years without moving, and it didn't take any bolts at all :)
It was going to be to run a decking joist along the edge/side of my shed's concrete base instead of having the joist up on posts but the dimensions don't work for bolting it to the concrete anyway.
What's the magnitude and direction of the load? I've had a 2" thick piece of timber sat on a concrete floor for years without moving, and it didn't take any bolts at all :)