2008/0169 Response to information request - 71 Seaview Tce Sunshine Beach · 132008.169

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      •   Areas behind contiguous piled walls will he fully drained by using
          drilled-in steel "wick" drains, connected through the base of the wall
          and discharged appropriately
      •   Upper structure comprises reinforced concrete columns, walls and
          beam/slab system
      •   Roof spans vary up to 12m, requiring lm-2m deep cambered concrete
          beams
      •   Roof/driveway slab will need a high grade trafficable waterproof
          membrane or a trafficable slab may be considered over an insulated
          waterproofing layer on the structural slab
      •   Garden terrace areas will be generally constructed on screw piles,
          ground beams and suspended slabs over voids to avoid imposing
          additional soil loads to the steep sandy slopes
          The pool/bedroom area, etc will be constructed of concrete slabs and
          beams supported on galvanised screw piles penetrating at least 5m
          below the 27° slip line, projected from the base of the slope, and 7m
          below natural ground
      •   The elevated timber walkway running east-west from R.L.34 to
          R.L.26.2 will be supported on 7-8m deep piles, designed to withstand
          lateral drag of the loose surface sands.

6.2   Lateral Resistance

      The lateral resistance to wind, earthquake and lateral soil forces will be
      provided by reinforced concrete and hlockwork bracing walls, cross
      bracing, and a combined column/beam framing action. Raking tension
      and compression piles will be designed and certified by others based on
      their own design-construction methods and shall have the capacity to
      safely resist horizontal loads from wind, earthquake and lateral soil
      pressures, with a permanent factor of safety against sliding exceeding 2.0.

      It is clear that the construction of the fully strutted and braced deep
      contiguous piled walls will add significantly to the general stability of the
      slope and of the areas uphill from all sections of new work, including the
      adjacent properties.

6.3   Drainage

      The areas behind the contiguous piled retaining walls will be drained by
      the use of vertical perforated "wick" drains at approximately 4m centres,
      connected through the piled wall just at the underside of the floor slab
      level.

      The design will include 100mm sleeved agricultural drain lines in gravel
      and geotextile at the bottom of all retaining walls and under all floor slabs
      in cut areas throughout the building.

      Properly designed temporary and permanent drainage and silt collection
      must be installed to avoid the risk of surface sands washing off site, during
      and after construction of the project.


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