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

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Our design and suggested construction procedure has taken into account
the critical staged nature of the proposed excavations, close proximity of
adjacent properties (especially the piled pool structure), the additional soil
loadings due to the uphill gradient, the loose and unstable nature of the
upper sand layers (particularly when vegetation is removed or disturbed)
and the limitations of piling machine size which can access the site.

The key features of our design and construction proposed are:-

•       Stabilise surface sands along western boundary using i1RETEK (or
        similar) ground injection
•       Establish survey markers across site and on adjacent properties for
        continual regular monitoring during construction
•       Install extensive "Sediment/Erosion Control" fences
•       Install temporary stormwater collection and disposal system; install
        permanent 450mm stormwater drain in short sections, spoon drain and
        gully pits along west boundary.
•       Avoid ground vibrations
•       Prepare engineered truck turn-around area(s) and access tracks/ramps
•       Construct piled temporary access or engineer-designed cut-fill access
        for 50T CFA pile rig and complete the western contiguous piled walls
•       Progressively remove sand east of new walls and establish temporary
        propping or ground anchor system. The ground tension anchoring
        would be the more economical procedure if adjacent owners give
        permission, but if this is not allowed, compression strutting is quite
        feasible within the site, or top-down construction could be utilised.
•       Extend temporary access/storage/ramp areas towards north and back to
        south-east
•       Complete roof stab (top-down method) for the main house structure or
        continue excavation and propping/anchoring to required levels
•       At all times the retaining walls are fully propped, drainage is in place,
        and the CFA piling rig is operating on stable flat platforms without
        any risk of slip or toppling
•       Floor slabs laterally restrained by raking piles will provide permanent
        horizontal strutting to the base of retaining walls
•        Excavated sand can be removed by small hoist, conveyor belt, or crane
        to dump trucks and used as excellent clean fill at another project
•        Piling contractors have advised it is quite feasible to move the CFA
         piling machine on rubber matting or use rubber tyres on the tracks
         from the Seaview Terrace cul-d-sac to the site
•        Once the contiguous piled retaining systems, piling, screw piles and
         raking piles are in place (gradually progressing downslope), the
         remaining work will be typical formed in-situ reinforced concrete
         construction
 •       Sub-floor drainage will be connected through all contiguous piled
         walls into vertical "wick" drains at approx. 4m centres
    •    Grout piled walls will be patched and grouted where necessary
    •    A "dry" internal masonry wall and drained cavity will be provided at
         all contiguous piled retaining walls


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