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Extra Reinforcement

Discussion in 'Hardscaping' started by spk64, Jan 17, 2008.

  1. spk64

    spk64 LawnSite Member
    Messages: 3

    I have a question related to a small wall 35' long x 4' I am building. Using Anchor Diamond block (6"x16"x12). The building site will be level above the wall.
    Per their specs you can go to 4' without reinforcement. After reading all the threads related to a wall this height. I would feel better adding some geogrid.
    What would you recommend to beef this type of wall ? I have seen earlier post about adding a single layer 2/3 the way up the wall. But most 4-5' tall reinforced walls seem to have a layer near the bottom and a layer 2/3 the way up. This sounds like the best approach. 1 layer 4' wide at the 2nd course with the 2nd layer at the 6th layer.

  2. ChampionLS

    ChampionLS LawnSite Bronze Member
    Messages: 1,066

    That sounds about right for the information you provided. Whats going up on top of that wall? You should never have a flat surface behind a wall, where water can percolate down and get behind the wall. If it's lawn area, or a planter, it should be pitched forward and allow the water to run off the block. Be sure to include a drain field behind the wall too.
  3. spk64

    spk64 LawnSite Member
    Messages: 3

    The area above the wall will be lawn\patio area. There will be pitch to get the water away from the area. 12" of #57 behind the wall with pipes to daylight.
  4. mrusk

    mrusk LawnSite Gold Member
    Messages: 3,260

    I would do a 4 ft pull after the 2nd course and 5th. Or to be really safe go 1st 3rd 6th.

    Messages: 18

    Your approach sounds like more than enough, ecspecially combined with that particular block at that height.
  6. JimLewis

    JimLewis LawnSite Fanatic
    Messages: 6,872

    Well, there are several factors you should really be looking at to determine whether or not to use the geogrid.

    First, Height. You already know that one.

    Second, Condition above the wall. Is there a slope behind the wall? OR will there be a surcharge directly behind the wall? You already said it's flat behind the wall. So that's good. But what about a surcharge? What's going to be planted or sitting directly behind that wall? A concrete patio? A parked car? Sod Lawn? Just a few flowers?

    Third, Soil type underneath the wall and wall base. You need to be concerned with global stability. If the soil underneath the wall is more clay based, then I'd encourage you to use the grid. But if it's very sandy or rocky soil, you may be able to get by without.

    Fourth, water and rainfall. Even if the wall has good drainage built into it, a wall built in a rainy climate where there can be periodically times where there is a lot of hydrostatic pressure behind the wall can be a lot more prone to failure compared to the same wall build in a climate that doesn't get much rain or water.

    I am no expert. I know there are guys on this board who know walls even better than I do. But these things [above] I do know.

    OUTLANDER LawnSite Senior Member
    Messages: 576

    i think you'll be alright with what you came up with(just as precautions)as to the type wall you're using is very heavy.........that sounded like what we'd do

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