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Thread: light pole bases / foundations question

  1. #1
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    light pole bases / foundations question

    I'm going to be installing 5 light pole bases which will be a first for me. The specs say 5' in the ground with rebar cage but that's about it. How do you guys make the rebar cage? Sections tied together to make a square then several of those tied to vertical sections to make a 3D rectangle? I saw one post where the horizontals were bent in circles with verticle bars tied to it to make it a cylinder. I guess you would do that with a torch? Also I planned on putting my sono tube all the way down into the ground the 5 feet but I saw an older post where some disagreed with that. Also can fiber reinforced concrete take the place of rebar? I can make the decision even though the specs say rebar. The specs are borrowed from another contractor that put poles on this property previously.
    *Sometimes I wonder why the frisbee keeps getting bigger...and then it hits me!

  2. #2
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    If spec is rebar use rebar, round square, no matter tie pole base bolts to rebar; tube in or out of ground no matter.
    Just get the crete in befor it rains.
    No spec or drawing of what is required? follow what the other guy put in.
    How tall are the lights? 5' deep should be ~20' pole.

  3. #3
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    Quote Originally Posted by sameguy View Post
    If spec is rebar use rebar, round square, no matter tie pole base bolts to rebar; tube in or out of ground no matter.
    Just get the crete in befor it rains.
    No spec or drawing of what is required? follow what the other guy put in.
    How tall are the lights? 5' deep should be ~20' pole.
    Be careful what you install, here we require an engineers stamp on light pole bases.

    Jobs like this is where I lose all of my sympathy for EC's screaming about guys doing electrical work. Leave the concrete work to the concrete contractors.
    I can build anything you want if you draw a picture of it on the back of a big enough check.

    There's no substitute for hard work....but that doesn't mean I'm going to give up trying to find one.

    John Childress
    Electrical Inspector
    IAEI / CEI / C10
    Certified Electrical Inspector

  4. #4
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    Aug 2011
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    Southern California
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    Typically there is or has been a structural design for the pole base. It depends on hieght, weight and style of the pole in addition to the wind rating of the location its in. I have done tons of light poles and the concrete contractor will build the specified rebar and install into the sono-tube that they install as well. The sono-tube is usually recessed in the ground just far enough to where you wont see the end of it. No need to have it all the way down. Once the sono-tube and rebar is installed, then you install your conduit then they pour the concrete. I just stub the conduit out of the area then tie it in after concrete is done. The diameter and length of anchor bolts are to be specified and supplied by the light pole manufacturer.

  5. #5
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    Quote Originally Posted by Electron_Sam78 View Post
    I'm going to be installing 5 light pole bases which will be a first for me. The specs say 5' in the ground with rebar cage but that's about it. How do you guys make the rebar cage? Sections tied together to make a square then several of those tied to vertical sections to make a 3D rectangle? I saw one post where the horizontals were bent in circles with verticle bars tied to it to make it a cylinder. I guess you would do that with a torch? Also I planned on putting my sono tube all the way down into the ground the 5 feet but I saw an older post where some disagreed with that. Also can fiber reinforced concrete take the place of rebar? I can make the decision even though the specs say rebar. The specs are borrowed from another contractor that put poles on this property previously.
    It is a good practice to embed the anchor bolts into the base and have standoff nuts to keep the base of the metal pole from sitting on the concrete, leaving a 1-2" air-gap. It avoids corrosion of the base and the pole to fall over.

  6. #6
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    Quote Originally Posted by weressl View Post
    It is a good practice to embed the anchor bolts into the base and have standoff nuts to keep the base of the metal pole from sitting on the concrete, leaving a 1-2" air-gap. It avoids corrosion of the base and the pole to fall over.

    It is also a bitch to level the pole if you don't use double nuts ......... but of course I have never seen anyone try to just crank a site pole tight to the concrete, that would be dumb.

    Typical spec is double nuts, level the pole and grout under the pole leaving a nice chamfer to let the water run off.

  7. #7
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    If you can find someone to do the bases have them do it. We have done it in the past but have seen a few put together. None have fallen yet so they must be good, right? What will work in good undisturbed soil won't be worth diddly in the sand just a few miles South of here.

    We helped set a small wind gen a few weeks ago and the persons responsible for that base used fiber instead of a large rebar cage. They still had a small cage around the base bolts.

    Google light pole bases or something similar.
    Tom
    TBLO

  8. #8
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    Quote Originally Posted by cowboyjwc View Post

    Jobs like this is where I lose all of my sympathy for EC's screaming about guys doing electrical work. Leave the concrete work to the concrete contractors.
    I couldn't agree with you more. They have the tools, the technique and the knowledge. Do what you do best and sub the rest.

  9. #9
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    Palm Bay, FL
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    The specs I have are for 30' poles. I'm putting in 20'. Like I said in the first post I'm borrowing the specs from another contractor since he just put some poles on nearly this exact site. We have no inspection authority we have to answer to we just need them not to be blown over. I figure if I use specs for the 30' poles I should be good. I will have help from people that have installed these before I just want to have an idea of what I'm doing beforehand. So what I have so far is:

    Dig hole with auger,
    build rebar frame,
    use plywood pattern to position anchor bolts,
    attach anchor bolts to rebar,
    install rebar frame in hole (use something to keep it off the bottom of hole),
    install conduit stub-ups and tape or cap,
    install section of sono-tube above ground with reinforcing wood frame/stakes to keep it in place,
    pour concrete,
    keep anchot bolts level,
    wait for curing,
    remove sono tube, plywood,
    install pole & wire
    *Sometimes I wonder why the frisbee keeps getting bigger...and then it hits me!

  10. #10
    Join Date
    Aug 2011
    Location
    Southern California
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    Quote Originally Posted by Electron_Sam78 View Post
    Dig hole with auger,
    build rebar frame,
    use plywood pattern to position anchor bolts,
    attach anchor bolts to rebar,
    install rebar frame in hole (use something to keep it off the bottom of hole),
    install conduit stub-ups and tape or cap,
    install section of sono-tube above ground with reinforcing wood frame/stakes to keep it in place,
    pour concrete,
    keep anchot bolts level,
    wait for curing,
    remove sono tube, plywood,
    install pole & wire
    Dig hole
    set sono-tube staked off with 2x4's
    build rebar and drop in tube
    hang rebar cage from top of tube via steel stake bridge and tie wire
    install conduit stubs
    build plywood template for anchor bolts and assemble with 4" of exposed bolts
    pour concrete
    install anchor bolts into wet concrete and square off
    pull wire before you set the pole

    This is the norm here in CA, may be different in other places, but I have never seen the anchor bolts attached to the rebar, instead they are at least 24" long with a "L" on the end buried in the high strength concrete.
    Here is a generic sample....
    Attached Images Attached Images

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