Geotechnical Report (1) · MCU21/0212

                              PROPOSED RESIDENCE
                              66 SEAVIEW TERRACE, SUNSHINE BEACH

If steel screw piles are adopted, it will be important to ensure close supervision of installation, as piling may
not encounter sufficient drilling resistance (from torque measurement) in sands at the suggested founding
depth, and piles could extend to much greater depth than necessary.
It is therefore recommended that site specific static load testing be conducted from screw piles, if adopted, at
a minimum. Where tension or compression capacity developed in the footings is critical for the future
structure (e.g. resistance to uplift forces from high winds), then cyclic load tests (including measurement of
deflections under tension and compression cycles) should also be undertaken prior to construction.
Kentledge for static testing, or simulated cyclic loads, should prove the piles to a minimum of two times the
expected working load within tolerable deflections.

Ultimately, the advice of a specialist piling contractor should be sought regarding pile design and
construction. However, where steel screw piles are adopted site specific load testing and the results of this
geotechnical investigation should be considered by the structural engineers in validating any generic torque
to capacity ratios provided as part of the proposed design. An assessment of potential vibration effects on
nearby structures and monitoring requirements should also be included.

Footing design should also account for potential soil reactivity to be equivalent to Class M. It should be noted
that the placement of reactive clay may result in a more significant equivalent site classification, such as Class
H1 (or higher).
All footings should found such that they are not adversely affected by any adjacent excavations, trenches,
retaining walls, or in ground structures that are not designed to support building loads. Footings should
found at least below a plane extending 1 m horizontally from the base of trenches/excavations/retaining
walls/swimming pool, then rising up at 1V:1H, as illustrated in Text Figure 12.




                            Text Figure 12: Footing depth required to prevent undermining

Site drainage should be designed to readily remove surface water and to prevent ponding of water on
subgrade areas during construction and also adjacent to foundations and perimeter slabs once construction
is completed.

It is recommended that footings be inspected by a suitably qualified and experienced engineer prior to
placement of steel reinforcement and pouring of concrete to confirm allowable bearing pressures and
cleanliness of excavations (depending on foundation methodologies).

If any soil conditions encountered during construction are found to differ from those noted in the geotechnical
investigation, Tectonic should be notified immediately and an inspection carried out to determine if changes
to footing design are required.




23 November 2021
Report No. 21370-001-Rev0                                18