Gallery extension begins with geotechnical testing
Published on 05 December 2023
Work has begun, as three geotechnical tests took place on the site of the planned Forrester Gallery extension.
Cone Penetration Test (CPT), hand auguring and sonic drilling tests were conducted on the land assess the quality of the ground, allowing for more cost effective foundations and an understanding of the environment for construction. More information is available in the attached fact sheet.
The former Bank of New South Wales building was also originally home to the manager of the bank, with an extension to the rear of the building containing a laundry and other household functions. When construction does begin it is expected, although not certain, that evidence of the extension will be unearthed.
The extension to the 1884 Category One heritage building is scheduled to begin construction in 2024, with a planned opening date of March 2026.
Earlier this year the Regional Culture and Heritage Fund awarded a $6.5 million grant which, alongside contributions from the Lottery Environment and Heritage Fund, the John Westwood Christie Trust and the tireless fundraising efforts of the Friends of Forrester Gallery, allowed the long proposed project to move forward.
Waitaki District Council Museums and Gallery Director Chloe Searle: “It was very exciting for me and the team to see the machinery on site for the geotechnical tests. It makes the project feel very real now after years of planning and fundraising work.”
Geotechnical Testing Fact Sheet
Cone Penetration Test (CPT) up to 15m deep or to refusal x 2 tests.
CPT is performed by hydraulically advancing a penetrometer rod into the ground while measuring tip resistance, friction and pore water pressures. This testing will supply high quality information vital to making cost effective foundation and environmental decisions.
CPT data is used to:
- Detect soil layers to centimetre accuracy
- Assess soil properties, such as type, relative density, shear strength, stiffness
- Assess soil liquefaction potential
Hand augering (1.5 - 2m depth) x 2 tests
Sonic Drilling - 2x 15m boreholes, including Standard Penetration Test (SPT)
13 per hole at 1.5m spacing.
Sonic drilling is an advanced soil penetration technique which uses highfrequency energy generated inside a sonic head to advance a core barrel downwards through the required substrate.
The vibrations emanating from within the sonic head have a liquefying effect, loosening the surrounding soil structure’s integrity and allowing for smoother drilling as a result.
Once the core barrel has been advanced, the rig’s telescopic casings are placed over the core barrel. This then enables core retrieval to take place with no risk of collapse, even in more unconsolidated substrates. Core samples obtained is used for lab analysis to determine the geological context and behavioural type of the material.
ENDS