Following the Canterbury earthquakes, BRANZ's structural testing and research contributed to significant retrofit cost savings. It also led to improvements in seismic performance of new New Zealand homes.
Saving millions in strengthening costs
The Ministry of Education saved $800 million in expected costs following our full-scale lateral load testing of timber-framed school buildings. This testing demonstrated that a significant number of timber-framed classroom blocks in New Zealand did not need retrofit strengthening.
Improving seismic performance of New Zealand homes
Our investigations into light timber-framed homes affected by the Canterbury earthquakes identified the need to change seismic bracing guidance. This was the basis for a step-by-step seismic design procedure to improve the performance of New Zealand homes during earthquakes.
Engineering assessment guidelines
Findings from these and other projects contributed to the engineering assessment guidelines. The guidelines provide a technical basis for engineers to carry out seismic assessments of existing buildings within New Zealand.
Guidelines for multi-storey light timber-framed buildings
We conducted research into methods for designing light timber-framed (LTF) buildings beyond the scope of NZS 3604:2011 Timber-framed buildings. This resulted in guidelines for designing LTF buildings up to 6 storeys and includes design methods and guidance for seismic resistance, diaphragms and shear walls. A design example of a 4-storey apartment building is also included.
- SR475 Investigating the impact of the 2019 BRANZ guide on multi-storey light timber-framed buildings
- Multi-storey light timber-framed buildings in New Zealand: Engineering design
ReCast floors project
A national BRANZ-backed research project about the seismic performance of precast concrete floors, ReCast, has led to a Building Code change and to practical solutions keeping people safe.
Precast concrete hollowcore flooring, typically used in multi-storey commercial buildings, performed poorly in the Kaikōura 2016 earthquake. Research conducted under this project provided evidence to effectively stop the use of this system in New Zealand. An amendment to Verification Method B1/VM1 in November 2023 removed the deemed-to-comply pathway for the design of the supports for hollowcore floor systems.
Enquire about structural testing services
To contact our structural and seismic research team, you are welcome to:
- email branz@branz.co.nz
- phone +64 4 237 1170.
Updated: 15 February 2024