View Full Version : Mainline Anchor Post
Amber Gold
09-18-2014, 03:45 PM
Last year, I built a pump house for my vac. pump and electric releaser. I kept it short and my three mainline wires go over the pump house and sap tank to anchor on a tree on the other side of all this. The wires are at neck height and obviously are a nuisance, so I want to take them down. To remove this hazard, I want to put a post in front of the pump house to anchor the mainlines too. I'm thinking a 4x4 PT post, 3-4' in the ground embedded in concrete, with a cable from the top of the post back to the current anchor tree to keep the mainline from pulling the post over. The subgrade is a very hard, dense material, so I don't have concerns about the ground failing. I know mainlines put a pull when they anchor on the tree, so I wasn't sure if this would work. What do you think?
Once I do this, the mainline wire's now going to be too short to do anything else with it, so I want to make sure I have a viable solution before I start cutting things. I'll have my tractor over there soon with a posthole digger, so I can get the job done before frost sets in.
Thanks for the help.
BreezyHill
09-18-2014, 06:32 PM
That is going to be too much for a 4x4 use 6x6 or a tele pole. This past year I have snapped three 4x4 with just fencing strains of 250 # tension. The newer stock is not as tough as the old stock.
Short wires are easily spliced with a reef knot.
Not a fan of concrete on the upper part of a hole. To much frost lift action. Frost can lift a smooth post easily. Just think what it can do on a concrete collared post. drill as deep as possible 4'+ and leave the concrete at the depot. Top guide will hold the top well and the 4' will hold the base.
Ben
maple flats
09-18-2014, 08:30 PM
I have some posts that are in concrete (they are 8" concrete posts made from filling sono-tubes). They are 4 1/2' in the ground and below grade I have 2' of sono-tube set in a 12" hole that extends to the full 4 1/2' depth. In 8 years they have not moved. I think the issue with frost heaving is only when frost can get under the concrete or you have a taper that the frost can lift be pushing inward on the sides of the smaller diameter lower portion. Mine happen to have very heavy cash boxes anchored to them for two pay stations in my u-pick blueberry fields. Inside the sono tubed concrete posts I have 2 rebars and 2 J bolts to anchor the 3/8" wall steel pipe cash boxes on top of the posts. I truly believe if someone hooks a chain to their bumper to pull the posts that the bumper would be on the ground when I found the attempted theft.
BreezyHill
09-19-2014, 09:47 AM
Apples and Oranges.
Sono tube is designed to resist frost in the same fashion that friends in Alaska use grease on any pole that is placed in the ground so that moisture is unable to attach to the sides of a post and lift when freezing.
Concrete is a fairly good conductor of heat. By going down 4.5 feet the ground temp of 50 degrees will keep the lower portion of the post in a heat well and warm the post to limit frost action.
Wood is not a good conductor. 1 R value of insulation is equal to one inch of wood. So the wood will be much easier to have moisture attach to the pores of the wood and lift very well.
Taper action is when farmers need to redrive fence posts annually that are pointed and not in the ground very deep. Concrete cap around a post will amplify taper action.
Concrete post would definitely out live most any other material as long as it is sealed periodically with a silicon treatment as is used on concrete feed mills or painted with a concrete paint. Additional connection points can be added by drilling and using stainless fasteners and unistrut channel. 9827.
The pic is two unistrut channels with a 3" PVC manifold clamped onto them. There are four 1/2" wedgeloks holding the channels to the sugar house wall. This is a dry line manifold. Support wires are attached to the unistrut by way of L brackets on the channel lock. This product and supplies are available at Home Depot.
Ben
markct
09-19-2014, 01:59 PM
how about a post 6x6 atleast that is in the ground and also up higher than head level so the top can be anchored back to a tree which can be further away
lpakiz
09-19-2014, 03:14 PM
I am not a fan of anchoring very high on a tree. The tree will sway, moving and working anything anchored to it.
1 1\2 or 2 inch pipe will work, but look how the power companies anchor their lines. Anchors attach at the same height as the load, and are pretty steep to the ground. The ground will be able to hold its own if the anchor cables/wires are at the top of your pipe, opposite the load. I use two anchor cables, to keep the post stable from side to side.
If this system is used, I think even a 4X4 would work.
Amber Gold
09-19-2014, 04:30 PM
6x6 won't cost much more than a 4x4, so that's no problem.
The mainlines are coming in at about 4' off the ground, I was going to set the cable anchor at about 7' so I could walk under it even with a little snow. I could put a brace back to ground on the mainline side of the post to brace it in that direction as well. I can set the post, attach the mainline to it, and see how it reacts the load to see what bracing/anchoring required...whether in front or in back. My main concern was knowing that I could do this and not be left wishing I hadn't if it didn't work. I know I can splice wire if needed, but prefer not to...potential point of failure with the stress we put on these wires. Square knots do work well when needed. Gripples work until they fail.
In the woods, the frost generally doesn't get very deep because the snow insulates the ground. Two years ago, I set a side tie post in January with a manual post hole digger...<6" of frost. I drive temporary steel posts before maple season, and it takes some hammering at first, but you get through the frost after a few inches.
Unistrut' handy stuff, and I didn't realize Home Depot carried it. Thanks.
Thanks for the ideas guys. Appreciated.
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