The Fence

In doing a bit of research for this post I came across this story from here:

There once was a little boy who had a bad temper. His Father gave him a bag of nails and told him that every time he lost his temper, he must hammer a nail into the back of the fence. The first day the boy had driven 37 nails into the fence. Over the next few weeks, as he learned to control his anger, the number of nails hammered daily gradually dwindled down. He discovered it was easier to hold his temper than to drive those nails into the fence. Finally the ! day came when the boy didn't lose his temper at all. He told his father about it and the father suggested that the boy now pull out one nail for each day that he was able to hold his temper. The days passed and the young boy was finally able to tell his father that all the nails were gone. The father took his son by the hand and led him to the fence He said, "You have done well, my son, but look at the holes in the fence. The fence will never be the same. When you say things in anger,they leave a scar just like this one. You can put a knife in a man and draw it out.It won't matter how many times you say "I'm sorry", the wound is still there. A verbal wound is as bad as a physical one.


Interesting and wholesome until that part about stabbing which is kinda creepy.

OK. so maybe what I did to ruin our fence wasn't out of anger or non-anger, but more just stupidity on my part. One day I thought I could take down a section of fence that separates our front yard to the back yard so that I could drive a truck into the backyard. It seemed like no big deal since I knew the fence section was about 8 feet wide and that the truck was only 6 or 7 feet wide.

Well, I forgot to account for the big bush on the left side that ate up about 18 inches. As I tried to come through, I could tell I was very close to the fence post on the right. I folded in the side mirror, passed it and all appeared to be well. I inched forward and then CRACK! the fence post fell over on top of my little brother Ryan, who was able to catch it as it was falling. I know he has quick, cat-like reflexes, but the way he caught the fence was a little too good. It was only later that he told me that he could see the side of the truck scraping on the fence post the whole time. I was like, "Oh, thanks for saying something." Not only did he not say anything, but he stood right where the thing was about to fall on top of him. Anyway, I might need some putty to fill the holes that my glares left on him that day.

We went through this past winter with no fence on the south side of our house. It wasn't that big of a deal, but the house looked funny and stuff in the backyard seemed a little less safe. Plus we need a place to contain the kids when we're tired of having them in the house. So fixing the fence became our first outside project of this year.

I started by digging out the old post. It came out easier than I thought. Thence I set up a string line and figured where the new post would need to sit.
The fact that the post needed to be replaced presented the opportunity of engineering a removable post system. I remembered that I had some L-shaped scrap metal things at my mom's house, so I used those as a sleeve to facilitate pulling the post out so more vehicles can come to the backyard if ever needed (I want to do a drive-in theater sometime). I wanted a tight fit so that the post wouldn't be too wobbly. As shown, I taped the metal to the post, but as not seen, under the metal I included some asphalt shingles to be spacers.
Realizing that good drainage is key in all earth projects, I planned to sink the hole to 4+ feet below the surface and backfill with gravel before concrete. I got to use the shop vac to get the loose dirt out when I couldn't reach anymore. The soil at about 3.5 to 4 ft below the surface seemed to be somewhat cemented and fairly brittle as if shallow groundwater was once up to that level, which is not all that good considering a mapped spring is fairly close to our house. I will have to do more exploration to see where groundwater really is.

Once the final depth was attained, I set 1-foot of gravel in the bottom of the hole. Similar to laboratory procedures for determining the dry-rodded unit weight of aggregates (ASTM C-29), a tamping rod was used to pack the gravel in.
I thence set the post and placed and rodded another foot of gravel around the post. This step was to aid in drainage and to squeeze the post in place while I prepared the concrete. I mixed 180 lbs of dry concrete mix to a fairly stiff composition and filled up the rest of the hole. Megan and Maggie came out and pushed their hands into the concrete. Maggie was not so sure about it at first but then a couple of hours later I spied her trying to do it again on the other side. She is so cute and a good helper even though she loves to raid my field bag and hoard my tire gauge and markers.
We let the concrete cure for a week and then came the fun part. Holy Sword in the Stone. That post did not want to come out!! So I drilled a big hole through it near the base. I drove a large diameter metal rod through the hole and then grabbed the jacks out of the cars and started forcing that thing out. I had to raise the post about 18 inches before it finally came free. The asphalt shingle spacers worked great. The post was snug, but not too tight and was straight as could be.

I got to use my new cordless drill to attach the hardware to the fence sections. It effortlessly drove those big lag screws. It is so nice to have a macho drill that can instantly sink screws like that. I then hung the fence sections and Voila! It is so awesome! I really like it. I was happy to see that I can complete an idea that comes from my head and still make it look good. It's a good feeling (maybe that's why I want to work at Home Depot).
These are some more pictures of the finished product.

I like the hardware shown here:

I'm a little worried because these are the biggest hinges Home Depot sells. As you can see, the tremendous weight of the big gate is causing the post to bend. This is where the summation of moments comes in handy. For example, consider the big gate to be a cantilevered load. Due to the cantilever, the weight of the gate exerts a lot of pressure on the post and makes the post bend in the direction of the weight. The moment is equal to force time distance. For simplicity the moment acts where the post is stuck in the ground. The moment cannot be greater than the post can bear. The amount of moment that the post can tolerate can be determined by the stiffness of the post material and the cross-sectional area of the post. Those factors relate to the moment of inertia and after a few more calcs that I don't remember, we can know how much moment the post can bear before breaking. Since I'm not all that sharp on my structural engineering, a quick visual observation showed excessive deformation in the post, and I concluded that the moment needed to be reduced if not completely eliminated by allowing the gate to become a span (simply supported beam) instead of a cantilever. So I screwed a block of wood to the other post to allow the gate to rest when not being used. Only problem is that the little gate and the big gate are not even across the top. Maybe that's not such a big deal.

I really like this gate and am happy that we fixed it.