What is Seismic Restraint?

In lay terms, Seismic Restraint, or ‘bracing’ as it is sometimes referred to is the adding of specifically engineered restraint systems to architectural and building services components within a building to prevent those components from swinging around excessively due to earthquakes and either damaging themselves or other nearby components, or detaching form their primary supports and becoming a fall hazard to the building occupants under. It is also necessary to prevent damage to the components in such a way that repair costs are minimized, even for relatively small shakes and would otherwise be unacceptable in accordance with the buildings expected performance and use.

What is required to be restrained?

According to The Building Act of New Zealand, ALL building elements are required to resist any expected loads they may encounter during their design life. This includes the building itself, and the internal non-structural elements. This is made to reasonably prevent injury or hazard to life, or unacceptable damage to property if a design level event were to occur – such as the Canterbury earthquakes of 2010/2011. In essence, this means that all permanent fixtures within a building must be able to resist loads such as gravity, wind, seismic etc. Simplistically this includes; Internal partition walls, ceilings and bulkheads, building services (Mechanical, Electrical, Plumbing, Fire, Lighting, AV & Security, FF&E).

Who needs seismic restraint?

In essence, ALL commercial buildings and projects require seismic restraint to varying degrees.
As a building owner – you are required to meet your obligations under Worksafe to provide a safe working environment.

Compliance with The Building Act is such a way to achieve this. It does not matter if the building is brand new or existing – all owners need to meet this obligation regardless.

If the building is residential, standalone, and you are the occupant – it comes down to owner discretion – since the risk is to your own property and yourself. Naturally this would not apply if there are sub-leases, rentals etc whereby members of the public would be at risk.

For builders – the risk is different. Irrespective of the intended use of the building, you are required, as a Licensed Building Practitioner to ensure the building you deliver is fit for purpose and compliant with all aspects of The Building Act and relevant codes. For most single dwelling houses this is not typically a problem. However multi-unit residential buildings will inevitably have a number of areas of concern.