MCU16.0099.01, RAL19.0036 & OPW 19.0282.01 - Response to Information Request (final) 10.03.2020 · MCU16/0099.01

Aurecon Australasia Pty Ltd            T +61 7 3173 8000
ABN 54 005 139 873                     F +61 7 3173 8001
Ground Floor, 25 King Street           E [email protected]
Bowen Hills QLD 4006                   W aurecongroup.com
Locked Bag 331
Brisbane QLD 4001
Australia




Memorandum
    To             Adam Pfitzner                                     From                     Con Sweeney
                   Matthew Dunworth, Mitti Goon,
    Copy                                                             Reference                247473-CROIBH
                   Tom Montgomery
                                                                     Pages
    Date           2020-02-19                                        (including this page)
                                                                                              8 + Appendices
    Subject        Cooroibah waterway crossing – access construction trafficability

A site investigation of the waterway crossing located on Lot 46 at 23 Jirrima Crescent in Cooroibah
included geotechnical testing at the concrete crossings edges, and assessment of the trafficability of
the concrete crossing. Discussions with the land owner about the crossing construction as well as
visual inspection notes have been detailed.

1          History of water crossing
The following information on the history of the waterway crossing was obtained from the land owner’s
recollection 20-25 years ago, when the crossing was first constructed:
◼     Initially around $900 worth of rock was dumped into the waterway to form a crossing. All rock
      eventually sunk into the waterway.
◼     The land owner was a concrete truck driver who would intermittently place leftover concrete over
      the waterway. Over time, the concrete gradually formed the existing crossing.
◼     The concrete strength may vary between 20MPa to 40MPa.
◼     It has been confirmed that there is no steel reinforcement in the concrete crossing.
◼     The concrete thickness varies between 200 - 400mm and potentially 450mm in the middle of the
      crossing. The concrete thins out towards the vehicle access edges on the eastern and western
      sides.
◼     Concrete lines the dam edge 1-2 m into the water on the southern side of the crossing (opposite to
      the property fence).
◼     It has been advised that RFSQ (Rural Fire Service Queensland) have previously used the crossing
      to access properties on the western side of the crossing in emergencies.

2          Visual inspection of concrete crossing
The following observations were made upon visual inspection of the extent of the concrete crossing:
◼     Crossing dimensions: 26m (East to West) x 13.5m (North to South). The crossing dimensions are
      marked on the image of the crossing in Figure 1.




                                              Project 239146 File Pavement repair design fee proposal: Curlew street 2020-02-192020-02-19 Revision A Page 1