I resolved to make a new gate. A better gate. A gate that would last forever. Or at least, for as long as the property owner lives.
The original gate was made with a frame of four 2x6s of unknown wood, with a fifth 2x6 as a diagonal brace and 1x6 slats filling the center. The whole thing was put together with nails and it had two hinges, held in place with fairly small lag screws.
My initial plan was to build a gate with four vertical and five horizontal pieces of 2x6 pressure treated lumber, with 4 hinges, the whole thing held together with coated Torx-head deck screws 3-1/2 inches in length. But when I got the initial frame assembled, I found it weighed a ton, and that was just 4 of the 9 boards. A quick Google search and some calculations gave a finished weight of over 175 pounds! Eliminating any of the horizontal boards would have left a large gap in the middle.
Then I noticed we had some wire frame panels. I picked through them and found there was one that almost perfectly matched the size of the frame. So I went with a frame of three vertical and three horizontal members, leaving four large holes. I then placed the wire panel over the middle and attached with with screws and metal strapping. I could have used staples like a normal person, but I prefer screws. The wire panel stuck up over the top of the gate by about 4 inches.
Some quick math and I came up with a finished weight of just 125 pounds, well within the 150 pound rating for each individual hinge. Because the gate had only 3 horizontal members, I could only use 3 hinges, but that's still way more than enough, and half again as much as the old gate.
Old gate hanging precariously behind the finished new gate.
I intentionally made the new gate slightly longer than the opening, so it would close against the posts on either side, which is much stronger than a gate that can swing either way. My initial plan was to have it open inwards, which would make it impossible for the animals to push it open, no matter how hard they hit it, but the ground was too uneven in the barnyard. So I had to hang it so it swung outwards. But this presented a new challenge, the hinges were now on the wrong side of the gate! The solution was simple, I just flipped the gate over. This placed the overhanging wire underneath the gate now, which led to my next problem.
I over-compensated for the wire and installed the hinges on the post too high, leaving a sizable gap underneath. While none of our current goats could get under it, it would be simple for baby goats, and the gap might encourage the dogs to try digging underneath. So I got some 1x4s and 1x2s from the garage and built another, lightweight frame underneath. I'm not sure what the 1x4s were, but the 1x2s are cedar. I held them in place with lots of screws.
Yes, the wire fence is distorted in one area, but it's cosmetic only and doesn't affect its structural integrity. It was the only piece that was the perfect size, anything else would have been too small or required extensive cutting.
The finished gate has 3 heavy-duty hinges attached to the gate with 5/8" carriage bolts and washers, and I put metal straps on the edges of the wood to prevent it from ever ripping out, the larger plates held in place with massive lag screws.
I would have preferred the gate open inwards, which would have made it nearly infinitely strong to resist animals inside the barnyard, so since it had to open outwards, I installed a heavy-duty latch. The loop goes through a 6x6 post and is secured with washers and nuts, while the hook end has 4 bolts, washers and nuts (I'm actually short one bolt at the moment, so it's only got a screw right now). The latch is self-locking and should be nearly impossible for the animals to manipulate with their horns. I may try getting a metal plate or something to reinforce the hook side. For now, this is the weakest point on the gate.
My roommate took one look at it and said, "I think you overengineered this."
Yeah, I do that.