Mark Center's OHP Ramp.
Love the site. It's very helpful for all interested.
I've been building a ramp in the backyard for quite some time. Here's the url and the skinny:
I got all the 2 x and 4 x wood from a place that contacted out to the local builders to take all their wood scrapes. These scrapes range from useless to nearly 16 foot in length, much of it straight and nail free. Each pick up load (Tacoma short bed), stacked as high as I could cost me $40 to $60 each. I use 5/8 "used" ply for the ribs. I used 5/8 (as opposed to 3/4) because; I found it for $9 a sheet at a used lumber place and I doubled up on the joists since that wood was so cheap and available. 3/4 is the way to go but you gotta use what's available and what's in the budget! In the end, 5/8 works fine as long as you use screw in most of the sections and you use at least 3 layers of ply surface.
I removed all the grass, leveled out the yard and put plastic down. This may or may not be a good idea. When it rains, the water pools under the ramp (I punched a few small holes in each pool, no biggie), but we don't get much rain. Also, the whole ramp sub structure is up off the ground a few inches so there is air flow at all times.
I used 2 and 3/4 inch screws to screw all the joists to the ribs. What a pain in the ass but the half pipe rides very hard and fast. And, I can take it down in sections when I want my yard back. I used one layer 7/16 chip board (not particle board) for the first layer. Off set the second layer of 1/4 inch chip board and then off set the third and final layer of regular masonite for the siding surface. I counter sunk each screw on the skating surface and I used a screw with a square driver head instead of the Phillips because those tended to snap off.
I'm working on the bowls right now. I'm using the same process as before, same wood, same resources. I may not put down the plastic. It won't have any coping on the deep end. It's a pain to get the pipe bent. I "may" glue down some cement coping but, since the deep end is over vert, is doesn't really matter. The shallow end will have a mixture of steel and cement coping. I wont have a "shallow to deep end" drop. I'm just going to bring the sides of the half pipe around in a circle, but, between the 11 and 1 o'clock section, I'm going to relax the transition so the drop in is easier.
I'd say the hardest part of building a bowl is the cutting of each and every joist. Every one has to be custom cut. Depending on theÂ radius you choose, etc., it can take anywhere from just a few minutes to cut one, to almost an hour. This is because of the compoundÂ angles, bevels, etc. If at all possible, keep it perfectly round and simple. I couldn't because of the lack of space in my yard. In short, my deep end is a decreasing radius. never, never, ever again!!!
When it's bowled out I'm going to fab up some sturdy telescoping poles (4 x 4 steel, etc.) to stick in the ground and stretch a green canvas cover over a PVC awning. Inside I will hang a couple of spot lights and a couple of fans because it gets real hot out here in the summer.
Lastly, I'll paint the sides green to blend in with the surroundings and I'll use rug and rug padding to sound proof it as much as I can.
I made up no plans for this. I referred to that Thrasher Ramp Book (somewhat of a help, though not really descriptive)and I just went for it. It will probably take me a year to finish it off, start to finish. I did it all alone, which is both good (I can concentrate and such) and bad (moving the sections around and countersinking hundreds of screws is tough on this 43 year old back!).
That's the skinny.