Touching base with the Town Hall project

Before the work was done the building was resting on its original unreinforced concrete piles on reclaimed land. But construction teams have, in phases, re-piled the building – propping the building up with steel, and installing new foundations.  

As part of that work rubber lead bearing base isolators have been installed throughout the building. Famous already in Wellington for being used in some of our most important buildings, like Te Papa and Parliament House, base isolators are a key part of making a building more likely to get through an earthquake safely.  

They’re a combination of rubber, steel, and lead. In an earthquake, they help the building move more gently than the shaking ground and dissipate the earthquake’s energy, which helps reduce damage to the building and what’s inside.   

Senior Project Engineer Eric Osborne, from Holmes NZ LP, says it’s a huge milestone to get that part of the project complete.  

“It’s one of the main critical structural elements of the project.  

"It’s been a huge effort from everyone involved. From the design team to the contractors, the subbies. It marks the next phase of the project now that the building has a resilient structural system.”  

The base isolators allow the building to move back and forth, side to side, but less than the shaking earth. They help limit the movement inside the building, helping to preserve the many heritage and important parts of Te Whare Whakarauiki.  

Inside the building are low friction sliders, that are like steel dinner plates sitting on top of columns, again allowing the building to move in a safer way during a quake.  

And yet another measure that’s been built into the refurbishment is something called a rattle space. 

This is a space around the base and sides of the building that allows the building to move without it hitting anything, like close buildings or walls.  

It’s not the first time the Town Hall has been strengthened, Eric says along the way they’ve seen evidence of strengthening done in the 1940s, 50s, and 90s.  

Eric says it was interesting to see what was done in the past, and how it compared to today’s standards.  

“There's a history around the whole building strengthening-wise as well as various work that was done to remediate damage that happened in previous earthquakes as well.” 

Below Te Whare Whakarauiki the basement has been dug out further, and fully waterproofed, another big milestone for the project.  

Now that the foundations have been safely laid, Eric says the next exciting milestones for the redevelopment of the building will be finishing the roof, and completing the auditorium ground floor, marking the first time the Te Whare Whakarauiki, the Wellington Town Hall has had a complete ground floor in years.  

Find out more about Te Whare Whakarauiki and other works in Te Ngākau Civic Square on our website.