Also how do you build a ramp up to an 18" high bridge on even dirt? Dig into the soil first? Never done this.

Yeah, I think it’s very similar to how we built the lake ramps….just dig into the dirt to sink the vertical boards underneath the decking below grade

Looks like we can level by 1/ dig off top layer of leaves n junk on the ground 2/ mark out the area. with string on spikes or else with 2x4s. 3/ add dirt from nearby (should be easy at this site) 4/ tamp down our dirt pile so it flat (need tool)

I think unless we want to rent a mechanical tamper thing, we should focus on subtractive landscaping rather than additive

Another approach: cut an angle into the beams, so the decking just slopes down at the end

yup I was thinking we could cut an angle, but i was thinking the angle would be on the bottom

from Home Depot:

Learning how to build a ramp for a shed is not as complex as building a ramp for accessibility but there are still plenty of variables.

Determine the rise needed and the desired slope. The rise for sheds is often only several inches and riding mowers can easily handle a 1:8 slope.

Pressure-treated lumber rated for ground contact should be used to build a shed ramp. Use a circular saw to cut triangular stringers based on your rise and slope measurements.

The nominal size of the boards you select depends on the ramp rise. For example, 2- x 6-inch lumber could be used as stringers if the rise is less than 5 1/2-inches; a rise greater than that would require a 2- x 8-inch board.

A ramp 4-feet wide will use four stringers; two at each outside edge and two evenly spaced inside.

Brace the high end of ramp with a 2-inch board that has been cut to length and rip-cut to the height of the rise. Use 3-inch exterior deck screws to attach it to the each of the stringers.

For additional support, cut smaller lengths of lumber to fit snugly in between the stringers and fasten with the screws.

Use 2- x 6-inch boards for the ramp surface. Cut them to length and secure to each stringer with the deck screws.

Stain or paint as desired. Use slip-resistant tape if extra traction is needed.

yup, i was thinking 2x8s here. doubled up like the main bridge?

The main 2x12s are on piers, right? So about 8" off the ground? I like the idea of the 2x8s ultimately resting in little trenches Fastening them to the main structure by bolts to the main 2x12 or an additional 2x8 seems fine. So I guess I'd favor using the existing 2x12, rather than adding a 2x8 on the ground just for this purpose?

the additional 2x8 is an extra part, but it frees us of having to cut an angle cut. It also has the advantage that it’s repositionable if the ground is re-graded. With a cut, it might have to be recut. But I don’t feel strongly either way, the angle cut isn’t hard.

1/ 2x8s in trenches and mounted to additional 2x8s 2/ leveling the ground at each end as described above

cool