Rfi - Scg 32167(S)

Floor Slab Details

The thickness and reinforcement for slabs on ground are shown on the structural plans.

Ground slabs may require thickenings or stiffening beams incorporated in their construction. It may be
advantageous to excavate them at the same time as the perimeter footings. Refer to the structural plans for the
locations and extent of these.

Where the stiffening beams intersect a perimeter footing, their base must be graded down to the footing base
level, 3 x N12 bars must be cogged into the footing and lapped 500 with the beams trench mesh. Refer to the
structural plans for details.

Where the stiffening beams intersect a blockbase or retaining wall, 3-N12 bars must be dowelled 150mm into the
blockbase and lapped 500 with the beams trench mesh. Refer to the structural plans for details.

A levelling layer under the ground floor slab is to comprise of granular material such as clean sand or crusher
dust compacted in 150mm layers. Either well graded sand or crusher dust can be used.

An approved polyethylene damp proof membrane of 0.2mm (min) thickness is to be placed over the levelling
layer. Laps are to be a minimum of 200mm and be taped. All service penetrations and punctures are to be fully
taped. The membrane is to be extended down the inside face of the perimeter footings and must continue under
any thickenings or stiffening beams.

Drilled Piers Supporting the Slab

Slab piers are required where there is more than 300mm of uncontrolled fill beneath the slab. They are to be
founded at a minimum of 300mm into the NATURAL MEDIUM DENSE SILTY SAND. Special attention must be paid
to the extra slab thickening required over slab piers as detailed in the structural plans.

Where drilled piers supporting columns or posts are not poured with the slab they must be connected to the slab
in the following manner:

   • 4-N12 bars must be anchored 500mm into the drilled pier and be bent 300mm horizontally into the footing
     or slab as required.

   • Where a column penetrates a beam or footing 3-N12 bars must be bent around the column to lap the
     trench mesh by 500mm both sides.

Steel Screw Piers Supporting the Slab:

Alternatively steel screw piers can be used to support the loads nominated in the structural plans. The slab piers
are to be designed and installed by a specialist contractor. Special attention must be paid to the extra thickening
and reinforcement required over each pier as detailed in the attached plan and details. The contractor must
satisfy themselves with the soils information contained herein to achieve the loads nominated on the structural
plans. Further testing may be required and is beyond the scope of this report.

Drilled Pier Reinforcement

                             Pier Depth mm        Perimeter Piers       Slab Piers

                                up to 1500        None required        none required
                                1500-2500          2xN12bars           none required
                                2500-4000          4xN12bars            2xN12bars
                                4000-6000          6xN12 bars           4xN12bars

Pad Footing Details

All pad footings must be founded to the depth nominated on the structural plans. Where this depth is not 300mm
into the NATURAL MEDIUM DENSE SILTY SAND they must be deepened down to this level.




     SCG Consulting Engineers                              4                                     SCG Ref: 32167(S)