Recent earthquakes in New Zealand have starkly revealed the vulnerabilities of our built environment, highlighting the importance of rigorous seismic performance requirements in the New Zealand Building Code. New legislation has emphasised the value of seismic resilience in protecting our heritage.

The challenge

One of Auckland's most vulnerable heritage buildings, the earthquake-prone Mercury Theatre, is located on Mercury Lane. Originally known as Kings Theatre, the Mercury Theatre was designed by architect Edward Bartley and built in 1910 by John Fuller and Sons. It stands as one of Auckland’s oldest surviving theatres. After waiting over a century, the Mercury Theatre has finally received the seismic upgrades it deserves.

Leading the project is Seismic Performance (SP) Ltd, an Auckland-based earthquake repair specialist. The team from SP warmly welcomed Simpson Strong-Tie and offered a rare opportunity to see the project from a unique perspective. They explained the challenges of strengthening the theatre's thick brick walls and ensuring their connections to the ceiling diaphragm bracing. They are collaborating with architect Pattersons Architects and Centraus Structural Consulting to not only strengthen the theatre but also restore it to its former glory.

The solution

SP has used Simpson Strong-Tie products and solutions for other seismic upgrade projects. The team were enthusiastic in explaining that the HTT4 holdown bracket uses 290mm long 16mm threaded rod, embedded 200mm deep into the walls, providing a cost-effective strong connection to the ceiling diaphragms. “We are going to upgrade this building to 70 percent NBS (new building standard),” said the project manager with a look of pride on his face.

The project manager explained that the HTT4 offers cost-effective, exceptional tension capacity over un-tested pre-fabricated brackets. The HTT4 is a single-piece formed tension tie — no rivets, no welding points and a 4-ply formed seat. No washers are required.

The results

The use of HTT4 Tension Ties, E5 Angle Brackets, Strong-Drive hex-head SD connector screws, and Set-XP Anchoring Adhesive in the Mercury Theatre project serves as an excellent case study of Simpson Strong-Tie products in strengthening structures against earthquakes. Simpson Strong-Tie is proud to provide products and solutions that contribute to building safer, stronger structures with improved seismic resilience for New Zealand.