Re: Bolting a safe to the floor. Need advise
I'd use a Hilti Drop in Anchor. 3/8" are pretty strong, we use em a lot for work. Though if you want something even more solid the 1/2" anchors work really good as well. The sell both short and deep anchors, the latter having more strength obviously. Drill to depth, use their setting tool to flare it, then buy bolts and washers accordingly, and you're GTG.
There's another type of Hilti anchor commonly referred to as "quick bolts". You drill these extra deep, however no setting tool is required. Just pound it straight into the ground. As you pound it in, it flares on it's own. However, you'll have to lift the safe up and over onto the anchor, as there's already a threaded end built into it. This is also very solid, but may be a lot more troublesome