All-orbital space station

[Daymare17]

Sorry for cross posting here and in the astronomy forum but the problem falls under both categories.

 

Imagine if you have a gigantic circular space station that is tethered with numerous space elevators, is concentric with the earth and spans the entire geostationary orbit (I think A.C.Clarke played with this idea in one of his early works). My question is, at what altitude would it need to be tethered to provide 1g of centrifugal force in the "roof" of the space station, so that people can walk around up there in a normal way?

 

Some numbers that might help, which i found from a NASA study but the interconnection of which I do not understand since I do not know the maths of centrifugal force. Can anyone who does, help me?

 

1 rotation per minute (rpm) gives 1g at the inner circumference of a "circle" that is about 1600 meters across. 1g is achieved at 3 rpm with a 200 meters diameter, and a 4 rpm rate gives 1g if the circle is 110 meter across. There are 1440 minutes in one day, which is the rotational time of a space elevator/station, thus it would rotate at 1/1440 rpm. Earth's equatorial radius is 6,378 km. LiftPort corporation, which are currently planning to build an elevator within a few decades, calculates a length of 100,000 km.