How long until abandoned bike can be cut from bikerack?

There are two old bikes on the bikerack outside my work. They are both very rusty (chains are rusted through). I have never seen these bikes be used since I've worked here; they've just always been on the bike rack.
They take up a lot of room and I frequently have to lock my bike to my coworkers because there is no more room on the rack.
Can I have these removed from the bike rack? I mean, legally? How long do I have to wait until it's no longer theft, just removal of abandoned materials?

Er, that should say that I lock my bike to my coworker's bike... not my coworker ;)

Just do it. If anybody complains, that is one of those cases where it is easier to apologize than ti get some twit to give you permission. If the chains are rusted through, just move the bikes off beyond the end of the rack.

depends. Why not ask your boss or human resources. If its junk and you are not going to sell it to make profit or use it to an advantage, you could take unilateral action to "remove" junk from the property.
I think I'd ask first and volunteer the removal.

It sounds to me like this is your employer's problem more than it is your own.

I'd place a sign on the bike rack that says "All Bicycles left here after midnight become property of COMPANYNAME" however, I'd think only your employer could do that.

They are not your bikes and it is not your bike rack. Find out who owns the rack and ask them to take action.