Redwood 2"x4" braces are placed between the beams, perpendicular to them. Each brace is about 1' in length. From above, the completed skeleton would look like this:
I used redwood 1"x3" stock for the slats that cover the skeleton. Each slat extends about 2-3" beyond the outer beams and is fastened to each of the three beams with finish nails. I spaced the slats about 1/4" apart.
I then attached small redwood blocks, 5 along each side, to serve as supports for the rails. The blocks are cubes about 1" on a side. The blocks are attached to the slats directly above where the slats are attached to the outer beams. I spaced the blocks evenly along the length of the bridge.
The rails, made from the same 1"x3" redwood used for the slats, are then attached to the tops of the blocks, and bent into a curved shape as they are screwed in place. This is probably the only tricky assembly step, since you have to be careful not to break the rails as you bend them into place. I used clamps to slowly bend the rails, screwing and gluing them to the blocks as I went. I used a waterproof wood glue to attach the blocks to the slats and the rails to the blocks, as well as 2" deck screws that extend through the rail, through the block, and into the slat.
I then gave the whole thing two coats of a semi-transparent gray deck stain. You could also just leave it unfinished since it's redwood, but I wanted it to last longer so I used the stain.
The finished bridge was installed over the stream:
From here, you can move on to any of the other pond pages: