Need to build a strong ramp for garage.

I'd think the least expensive and easiest option would be to get metal car ramps from a place like Harbor Freight - the small ones that allow you to get the car just a foot or so off the ground. I'd securely fasten them in the proper place with bolts through the floor. Otherwise, it seems you'd need to build a complex ramp system with wood that won't last or an expensive ramp from concrete.

https://www.harborfreight.com/solid-steel-auto-ramp-set-63250.html

https://www.google.com/search?newwindow=1&rlz=1C1SQJL_enUS800US800&biw=1280&bih=882&tbm=shop&ei=U_-sW_qlBJCuswX2oK_gBQ&q=metal+14%22+high+car+ramps+to+get+into+garage&oq=metal+14%22+high+car+ramps+to+get+into+garage&gs_l=psy-ab.3...353.1048.0.1742.5.5.0.0.0.0.452.452.4-1.1.0....0...1c.1.64.psy-ab..4.0.0....0.E5Eo7Jn67C4

Be very careful if that shed is not permanently attached to piers in the ground. If it is sitting on blocks if you drive in it with a car or truck the whole thing could shift. Another thought would be if the floor of the building is strong enough to support a vehicle.

The car ramp idea sounds good from Harbor Freight or local auto supply stores otherwise build a ramp using pressure treated wood and also check the load limit of the floor.

I built ramps to get my mower into my shed. The car ramps previously mentioned could/should work. My shed sits in the middle of the yard so when i attached them to the shed I hinged them so I just drop them down when I need them but they stand up just inside the door when not in use. Makes mowing/trimming around the shed really easy. May not be important to you.

Based on what I see in the photo you posted the supports do not appear to be strong enough to support a car/auto. This is why most garages are built directly on the ground to spread the load/weight of the car/auto over a larger area.

IF the garage is rated for a car and nothing needs to be done to the floor, I would get with a local cement contractor for the ramp. The size you need probably wouldn’t cost but a couple hundred bucks.

This may be an easy method

http://azoffroading.com/blog/do-it-yourself-wooden-car-ramps/

Curious to know what you ended up doing. We just had a Weather King 12' x 30' delivered and am facing a similar situation although it's not as high off the ground.

Hey did you find a solution. I'm facing the same issue also does the garage shift when you drive your vehicle inside/up the ramp.