Point Fraser, Perth, Western Australia
Background
Point Fraser is a public recreation reserve, of 6.13 hectares in area, on the Swan River Foreshore at the Eastern Gateway to The City of Perth.
In June 2008 planning approval was given by council for the final phase of the redevelopment consisting of an $18 million mixed-use hospitality development to be located west of the existing Causeway.
Three commercial buildings will be constructed on site with two of those buildings to be constructed on the foreshore. The third building will be constructed over the river itself providing a public boardwalk along with ferry and boat access.
Scope
CMW conducted a geotechnical investigation of the site in our prorating the following:
- Undertake a borehole investigation to depths of approximately 30 metres (~6 metres into Guildford formation) to provide more certainty with pile foundation levels;
- Assess the likely impact of acid sulfate soils on pile design; and
- Provide onsite testing of a test pile to assist in confirming the capacity of the underlying materials to accommodate working loads ranging from 200 - 2000kN
Findings/Challenges
Historical aerial photographs show that the site comprises land reclaimed prior to the 1950’s and therefore contains surface fill. Additional research indicated significant depths of recently deposited, weak and compressible alluvial / estuarine sediments of the Swan River Alluvium (SRA).
In the past, numerous investigations comprising of Cone Penetrometer Test (CPT) investigations had been carried out by other Geotechnical Consultancies. These CPT’s were conducted to refusal at depths of up to 24 meters below ground surface and confirmed the above mentioned conditions.
However, no one had drilled Guildford formation and it was our opinion that insufficient information had previously been obtained to adequately demonstrate the presence of appropriate bearing stratum and selection of relevant design parameters for the support of pile foundations with the proposed loads.
CMW investigated deeper ground conditions by drilling 4 machine bore holes into the Guildford formation and made recommendations for design parameters for Pile design.
The CMW team consulted closely with our client and provided them with three different Pile options, at various price points to meet their budget, along with ground settlement options for the foreshore structures.