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Soil classification - possible to turn a Class S site to Class A site?

Discussion in 'Development' started by Serendipitous, 15th Sep, 2015.

  1. Serendipitous

    Serendipitous New Member

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    14th Sep, 2015
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    Australia
    Hi All,

    I recently obtained a property that is classified as Class S and I would like your help.

    Is it possible to turn a Class S site to a Class A site? How much does the site work roughly cost?

    When mentioned about the expensive site work for class S (over Class A), what do we refer this to? Is this the structure/engineering of the building needs to be stronger, hence cost most? or is this referring to the preparation of the site?

    Thanks
    Serendipitous



    Extracts from the geotech report:
    • Strip off topsoil of approximately 100 mm. Topsoil can be re-used after screening off unsuitable materials.

    • Considering site condition, we strongly recommend that a qualified geotechnical engineer should visit the site after stripping of the topsoil so as to confirm that all the unsuitable materials and topsoil have been removed from the site.

    • Provide a sand Pad 700 mm from middle of the property to the rear of the road and compact as per AS3798.

    • Compact the site up to 1.05 m depth to a Dense condition. We recommend, 150 mm for seating, 8 PSP blows for 150-450 mm, 9 PSP blows for 450-750 mm and 10 PSP blows for 750-1050 mm.
    As the site is in loose condition, following steps can be considered:

    • Strip off top layer of approximately 500 mm. Boxing out of site soil and stockpile ready to replace. The depth of boxing out soil can vary based on the compacting equipment used onsite, considering site has to be in dense condition to a depth of 1.05 m from the existing surface level.o After compacting the base to dense condition, replacement of site sand previously boxed out. The maximum thickness of each backfill layer should not be more than 300 mm and each compacted layer has to achieve "Dense" condition (minium of 8 PSP blows per 300 mm penetration) until final recommended elevation is achieved.

    • Site should be prepared in a way so that surrounding stormwater does not pass

      through the building envelop. Care will need to be taken when compacting in the vicinity of existing structures to avoid damage from excessive vibrations. Retaining wall is required if there is an elevation difference of 0.5 m.
     
  2. clemont

    clemont Member

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    S class is not bad, will be worried if class P (due to KDR or fill).
     
  3. TML

    TML Well-Known Member

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    AS3798 does not define and explain the different classes of soil.

    Does anyone know which standard defines Class P , S, A , etc
     
  4. clemont

    clemont Member

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  5. Be Developer

    Be Developer Property Developer Business Member

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    Structural engineer will work around soil conditions. Just need to get right structural engineer to design slab.

    Is it ppor or ip?
     
  6. trivial

    trivial Member

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    Your founding material is good, but you're likely on a fill site over it.

    There is an old joke about Class A costing an extra $100 for the soil tester.

    You're after AS 2870.
     
  7. sdprop

    sdprop New Member

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    Yeah sounds like good foundation soil with crap over it. You are going to have to put a far few dollars into preparing your pad for the slab. As mentioned above talk to a structural engineer about the best way forward. The engineer may even come up with an alternative method so you can cut down on earth works expenses ie. piers.
     
  8. Serendipitous

    Serendipitous New Member

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    Australia
    Thanks guys. This is for an IP, not PPOR.

    Thanks @trivial and @sdprop .

    Omg......I just found out that the site IS NOT currently classified as class S; it states that it will only be Class S if the outlined recommendations were followed.....