I'm not in the business but I have gone through this before more than once. I've been a member of clubs where we had the exact same type of ramp built.
What you can do to keep people from using it is this:
When it is being poured, secure some vertical pipe (at least 3") on either side of the entrance to the ramp. Next, use a chain across the two pipes to form as a gate over the entrance to the ramp. You can either cut holes in the pipe or weld the chain to the pipes. We normally route the chain through the pipe and use a combination lock to secure.
