geotech

                              PROPOSED UNIT DEVELOPMENT
                              9 BOTTLEBRUSH AVENUE, NOOSA HEADS

Due to the presence of loose sands, open bored piers or driven piles are not considered to be suitable for
this site and it is expected that steel screw piles could be utilised. Steel reinforced concrete bore piles may
be possible; however, the use of sacrificial liners (e.g. formatube etc.) would be required. The advice of a
specialist piling contractor must be sought regarding feasibility, design and installation of the piling system
for this site, including an assessment of potential vibration effects on nearby structures, and monitoring
requirements.
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.

Footing design should also account for potential soil reactivity to be equivalent to Class M. It should be noted
that placement of reactive clay may result in a more severe equivalent site classification, such as H1 or
greater.
All footings should found such that they are not adversely affected by any adjacent excavations, batter
slopes, 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 10.




                        Text Figure 10: 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.

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.




13 July 2021
Report No. 21169-001-Rev0                               12