Sarjeant Gallery update
The detailed design of the Sarjeant Gallery's earthquake strengthening is complete, and we start the New Year with moves into the next stages of the project.
The redevelopment of the historic 100-year-old Sarjeant Gallery involves earthquake strengthening the existing heritage building and construction of a new wing – Pataka o Sir Archie John Te Atawhai Taiaroa, named in honour of the much loved Whanganui kaumatua.
The Sarjeant Gallery is listed as a Category A building with Heritage New Zealand and is in the Whanganui District Plan's Heritage Inventory. The hill it sits atop, Pukenamu, is an archaeological site under the Heritage New Zealand Pouhere Taonga Act 2014.
I'm honoured to be part of the team working to preserve this rare part of New Zealand's architectural history. The Sarjeant Gallery's national significance has consistently been highlighted throughout the project to date, and recognised by the magnitude of external funds raised for its future. Whanganui is fortunate to be kaitiaki of such a taonga.
Every step of the way we are conscious that the new earthquake strengthening solution is staying on budget and will be fit for purpose. The system has been peer reviewed by a team from Auckland University which specialises in seismic strengthening solutions.
With the seismic solution clearly defined, the contractor is soon due to resubmit the work method and price for our consideration.
The strengthening solution will be Post Tension Strand which is less intrusive on the intricate internal plaster-work of the historical building and more cost effective than the alternative base isolation system.
Stainless steel bars will be inserted through the existing outer layer of bricks from the roof to the basement with a concrete diaphragm on the roof and concrete foundation in the basement. Brick ties will stitch the interior layer of bricks to the outer masonry walls.
The result will be a hidden cage-like structure, appearing as if there's no obvious change, with all the traditional architectural features maintained.
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The gallery extension involves construction at the rear of the existing gallery building including some additions and changes to the roads and footpaths, service installations and landscaping and planting.
A small stand of oaks and Phoenix palms behind the Gallery will need to be removed this month from the site designated for the extension.
Planted in the 1920s, the trees are not protected or listed as having any specific heritage value.
The timber from the oaks will be milled on site and depending on the quantity and quality, we hope we may be able to use it in some way in the build.
New planting will be included in the later stages of the development.
The project is taking longer than expected as we work to finalise the archaeological authority needed to do any digging on a site with this level of historical significance.
It includes anything and everything that penetrates the ground. For example, where vehicles will be parked, the location of signage, scaffolding, the construction fence and site huts, all had to be captured in the application.
Next steps inside the gallery are to drill and test the best method of installation of the earthquake strengthening steel bars. Outside we'll be working on diverting stormwater which could impact the excavation due to start late summer.
•Gaye Batty is a project director at the Sarjeant Gallery.