Attachment C - Geotechnical investigation

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8.3 Footings
In accordance with industry standards, a geotechnical engineer from Arcos should undertake
the testing within the footings to confirm that the encountered material is in alignment with
the adopted parameters and assumptions provided within this report. Where this does not
occur, Arcos cannot be held liable for any of the information presented within this report.

All footings will need to be designed to accommodate potential ground surface movement,
settlement values and any additional settlement values associated with the placement of new
fill.

Settlement for suitably sized and designed high level footings should be in the order of 1-2%
of the width of the footing.

If footings are located adjacent to an underground service or other obstruction that is not
homogenous with the founding strata, the footing should be extended a minimum 0.3 m
below an imaginary line projected at a 45 degree angle from the lowest point of the
service/obstruction. This is depicted graphically for reference:




Where footings found into medium dense sands, they may be dimensioned for a maximum
allowable bearing pressure of 100 kPa. Based on the borelogs, the above material is
encountered at approximately 2.0 m depth below existing surface levels at the time of the
investigation. It should be noted, however, that in order to obtain a “Low” risk rating the
footings must be constructed at least 1.5 m into the medium dense sands. Therefore, the
footings should be founded to at least 3.5 m below the current ground surface level.


The ultimate geotechnical end bearing and shaft adhesion parameter are presented in Table
3. The values given will need to reduced by applying a suitable geotechnical strength reduction
factor (Φg) for limit state or divided by a suitable factor of safety for working stress methods.
The Φg should be selected by the designer.




09 Feb 2021                                                        Proposed Residential Dwelling