Anchor depth

My anchors are 1" diameter and expand after they break thru the concrete. They can never pull out.

As far as concrete strength 4" is plenty thick. Mine is 3 1/2" of six bag mix with fibermesh. I installed my lift in 1995. It's an older model Weaver made from 1" thick steel...weighs over 1500 lbs. itself. I have used it to lift my one ton vans and duallies. No issues ever.

Everyone goes beserk about lifts and thick concrete. I bought a HD 9K lift as it's much stronger than the cheap Chicom junk that had flooded the market. The concrete will never fail.