galaxy flyer
The PCNs for ramps and taxiways are not usually published by the airport, and there is no easy answer. I guess you have to ask each airport (and hope you get an answer - I often find that they don't know or won't tell).
Most airports will have strength data for each ramp and taxiway, and will taxi/park you where they think it is strong enough. Some do not have any technical data, and work off previous experience (which is little help if your plane is larger than normal). A very few are without care or attention.
If the airport is long established, the strength varies significantly between the different ramps and taxiways. Normally, the airport will deliberately map out a path of high strength taxiways and aprons to match the strength of the runway, so that a heavy plane can safely taxi in and park. When they overlay or strengthen the runway, they also work on this path of high strength taxiways and ramps.
But airports generally take a more relaxed view about overloading these because if you sink into a ramp, it can always be closed and repaired later. And if the thing ruts a lot, no-one is too worried because there are no high speed aquaplaning or roughness issues to worry about. The same cannot be said about the runway. My own place has high strength taxiways that are so badly rutted that they can't be fixed by asphalt overlay and will have to be rebuilt from the bottom up. But they still work, the surfacing is intact, and so we're not planning to rebuild anything just yet.
There are a couple of tricks for GLEX (and similar) pilots to use. When arriving at an airport for the first time, ask for high strength or airline parking (in case the airport doesn't realise that you are in the jet-airliner weight class). Then after you have parked and before you refuel, look at your tyres and the wheeltracks leading into the parking position and see if you have created progressively deeper ruts as you slowed down to a stop, or see if you are sinking in. If you have, drive or tug out of there before refuelling or loading.
If you have the luxury of checking out an airport before you operate there for the first time with a heavy aircraft, ask them to drive over slowly (also called proof roll) the suspect areas with the biggest fire truck or refuelling tanker. If it takes the weight of those, it should be OK for a 45 tonne aircraft. You can use a simple rule-of-thumb: each axle on a laden truck weighs 10 tonnes (or 20,000 lbs). So a small refuelling truck with 3 axles is probably 30 tonnes, and a fire truck is 20 tonnes. And if the pavement takes those without breaking, it should be OK for 1 pass of your 45 tonne (100,000 lb) aircraft.
Cheers
Overrun