Compiled Reference Documents - MCU24/0153 & OPW24/0202

        Given the sandy soil profile and depths of footings required, steel screw piles are considered to be a
        suitable foundation type for the proposed unit development generally. However, in areas of cut
        exposing medium dense (or denser) sands at the subgrade level conventional high-level footings may be
        adopted. It should be noted that excavation for concrete strip footings (or similar) may loosen the base.
        Therefore, the use of a vibrating plate and ample water would be required to densify any high-level
        footing bases prior to the placement of reinforcing steel.
        Due to the presence of loose sands, open bored piers or driven piles are not considered to be suitable
        for this site. Steel reinforced concrete bore piles may be possible; however, the use of casings or
        sacrificial liners (e.g. formatube etc.) would be required. Cast in place continuous flight auger (CFA) piles
        may also be suitable for foundation piles (and shoring piles) provided a small rig capable of traversing
        the site can be sourced.
        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 (which is not recommended) 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, 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 overleaf.




        Proposed Unit Development
        30 September 2024 | 24265-001-Rev0                                                                              14
Document Set ID: 23376055
Version: 1, Version Date: 28/11/2024