Methods used for setting post?

[wroughtn_harv]

A lot of the pole barns on this site are using square poles. The large poles are tapered just like the trees they come from. It's not a great difference, but you can tell one end is smaller than the other. If you ever watch them drive wooden pilings for houses (very common around here) you'll notice that they drill a pilot hole and drive the posts in small end first. I'll' try to find some examples on this site...


Here's one: The tall pole is obviously in upside down...

Hmmmmm, I think you might be incorrect in your assumption.

I've got close to forty years of being around fence work. At seventeen I went into the military and became first an infantry wireman, then a telephone lineman and finally a telephone cable splicer. After the service I spent about twenty years in telephone line construction. In all the years of being around my father doing fencework and working telco line construction I never heard of putting posts into the ground small side down. In fact telephone and power poles come with a bare number six ground wire installed. It is ran to the base of the pole and coiled for ground contact.

There's a lot of engineering in telephone/power pole design. In fact I'll bet the knowledgeable will tell you the telephone/power line industry has to be the most over engineered thing in the whole world.

Wood poles, steel poles, and concrete poles are all designed with a taper and the large end always goes down. I'm sure you're correct about them putting the smaller end down when driving them down. Path of least resistance and all that, not to mention the cavity created on the sides from the big end creating the hole size.

 

[bjcsc]

If we're talking about fence poles, power poles, etc. I would agree. The forces are different. You wouldn't want the heaviest part of the pole in the air for obvious reasons. However, if you're building a pole structure (the topic of this thread), with the majority of the weight transfer down, the small side always goes in first. It doesn't have anything to do with ease of pounding it in - the drivers can pound square in just as easily. It has to do with the weight being transfered along the length of the pole vs. just the tip (again, not relevant to fences and utilities). We're very close to sea level here and they build many houses on pilings. Every single one of them is driven small side down. Again, as I said, for the most part no one builds anything with loads that will matter. But if you intend to build a pole barn to store hay or with living space in the loft, it will matter. Read this.

 

[wroughtn_harv]

If we're talking about fence poles, power poles, etc. I would agree. The forces are different. You wouldn't want the heaviest part of the pole in the air for obvious reasons. However, if you're building a pole structure (the topic of this thread), with the majority of the weight transfer down, the small side always goes in first. It doesn't have anything to do with ease of pounding it in - the drivers can pound square in just as easily. It has to do with the weight being transfered along the length of the pole vs. just the tip (again, not relevant to fences and utilities). We're very close to sea level here and they build many houses on pilings. Every single one of them is driven small side down. Again, as I said, for the most part no one builds anything with loads that will matter. But if you intend to build a pole barn to store hay or with living space in the loft, it will matter. Read this.

I can see your point. But it's only applicable in one situation. That's where posts are driven. If you look a the photo where you show the post as being upside down they're in concrete footers. For your principle to be critical the hole for the concrete footer would have to be tapered. The only tapered augers I've been exposed to are those that have been wore down and should have been replaced at the first sign of taper.

One of the things I've learned about setting posts in clay is one of the worst sins is a tapered hole. The very resistance that's laudable in your driven scenario creates a serious problem in areas with expansive soils like ours. I'm sure the same thing is true where frost heave is a factor.

The resistance that you're talking about is desireable when you're driving pilings. However that same resistance gives heaving conditions grip to move posts up and out of their holes.

You might also consider that the primary reason for driving posts or pilings isn't their efficiency. It's because driving is much cheaper than pouring footers.

 

[bjcsc]

wroughtn_harv, OK so now we're teasing this out a little and I completely agree with you. I never even thought about the frost heave scenario. I appreciate your knowledge! So what do you do in those situations? What do you do in clay? Always pour footers? What about the concrete cookie?