Originally Posted by Robert C
I may show this, but I really need something that can be bolted to existing concrete. This design would require existing concrete to be broken, a hole dug and then the concrete to be patched in an attempt to match the original concrete. I really can not see anyone going for it. Designs that use an expansion bolt only require a hole to be drilled in the concrete.
I can see this being adapted to have a flat plate on the ends of the downtubes and then bolted in place. However, that would use a lot of bolts, and bolts are expensive. Think in terms of very inexpensive labor but very expensive materials.
I am thinking of asking that a steel cable be welded to the a couple of poles and then people can attach a lock to the cable. Remember, what you are defending aginst is a couple of guys driving up in a truck and throwing all the free locked bikes in the back and working on the locks later.
Drill a hole in the concrete large enough to drive in a peace of rebar matching the position of each end of the bike rack that will be contacting the cement. Fill the hole with grout or cement and drive in the rebar allowing enough of the rebar above the cement to provide a suitable length to be welded to the bike rack. After the grout or cement is dry weld the bike rack to the rebar. No one will be able to pull the bike rack out of the cement. Rebar is cheap and required lengths can be salvaged from construction sites.