Acid Sulfate Report

                              25 EDWARD STREET, NOOSAVILLE
                              PROPOSED DUPLEX DEVELOPMENT

maximum 250 mm thick (loose thickness) layers and be compacted by repeated rolling to achieve a dry
density ratio of at least 95% of the maximum Dry Density Ratio (Standard Compaction method), or 70% of
the Dry Density Index for cohesionless fills (e.g. sands).
Confirmatory compaction testing must be carried out at regular intervals. Details for inspection and testing of
fill are given in Australian Standard AS 3798-2007 Guidelines on Earthworks for Commercial and Residential
Developments. We recommend placement of structural fill to Level 1 standard and Type 2 frequency per
AS3798.

5.2       Building Foundations
5.2.1        Indicative Site Classification

Site classifications for footing design are determined in accordance with AS 2870-2011 Residential Slabs and
Footings, and depend on the depth of cut / fill undertaken at a site, variations in the natural soil profiles, and
the reactivity of the in situ soil / rock and any imported fill materials. It is recommended that imported fill be
non-reactive, inert material (e.g. roadbase type).

Based on the results of the investigation, the site is classified as equivalent to Class ‘H1’ in accordance with
AS 2870-2011 Residential Slabs and Footings. The estimated characteristic surface movement (‘ys’) due to
volume change as a result of moisture content variations at this site is expected to be less than 10 mm
(assuming non-reactive fill is placed). However, settlement from fill and building loads may be in the order of
30 mm to 40 mm (resulting from very loose to loose sand).

It should be noted that the predicted order of movement is based on the existing soil profile (i.e. no cutting or
filling), and moisture content changes within soils due to normal seasonal moisture variations only.

5.2.2        Footing Design

It is our recommendation that the proposed residence and any associated structures (e.g. pool and retaining
walls) should be supported on high level footings founding in future controlled (certified) fill. Conventional
footings (beams, strip, pads) may be adopted, and be designed for an allowable bearing capacity of
100 kPa.
If higher bearing capacity is required, deeper footings will need to be installed. Due to the loose nature of
the sands at this site, and in order to minimise ground vibrations, it is recommended that screw-in (helical)
steel piles be adopted for deeper footings. Piles founded on the dense sand layer at a depth of 3 m to 3.5 m
BGL may be designed using an allowable end bearing capacity of 300 kPa. Care must be taken so as not to
penetrate through the dense layer. Piling companies must provide their own assessment of suitable pile
types and capacity.

All footings must also found such that they are not adversely affected by any adjacent excavations, batter
slopes, trenches, or retaining walls that are not designed to support building loads (e.g. the existing sewer
along the rear of the site). Footings should found at least below a plane extending 1m horizontally from the
base of trenches/batter slopes/excavations/retaining walls, then rising up at 1V:1H, as illustrated in Text
Figure 7 below.




25 August 2017
Report No. 17265-001-Rev0                                7