“The main concern was that while some people on the team were familiar with sheet piling, no one was familiar with driving sheet piles immediately adjacent to the unreinforced brick masonry of the Town Hall. We weren’t sure how the building would behave once we started driving the sheet piles into the ground, as the vibrations would emanate through the ground and up through the structure.”
Visual monitoring of the site was undertaken by the team before the sheet piling construction started, so they could identify any new cracks or damage caused by the process.
“We were all ready to start the works, and then we had to check the building again because a magnitude six earthquake happened the night prior to the sheet piling commencing. The building remained safe and secure through this earthquake, and it was a testament to the structural design and construction," says Anthony.
“It was a really timely reminder about why we’re doing what we're doing, putting in the new foundations to strengthen the Town Hall and protect it against those sorts of events in the future.”
After around six weeks the sheet piling was completed. Since then, the team have dug out the basement for the NZSO rooms, toilets and stage lifts, and have begun the screw piling process for the auditorium foundations.