Pragmatic improvements to seismic resilience of non-structural elements

The recent Canterbury earthquake sequence and the more recent Seddon, Lake Grassmere and Castlepoint earthquakes have raised awareness of the vulnerability of non-structural elements of buildings (e.g. ceilings, cladding, building services equipment and piping, etc.). With architectural and building services components comprising up to 70% of a building's value, significant damage to these elements resulted in some buildings being declared economic losses, even when the structure itself was not badly damaged. Impacts on business continuity due to the damage of non-structural elements have also been identified as a major issue in recent earthquakes in New Zealand, as well as worldwide. It appears a step change is required in the seismic performance of non-structural elements in New Zealand. This paper explores whether the current approach being used in New Zealand for non-structural contractor designed elements is appropriate in meeting society's expectations. It contrasts the approach that has historically been taken in New Zealand, with that followed overseas. The paper goes on to explore a pragmatic "best bang for the buck" approach to upgrading non-structural elements in existing buildings. The approach is presented through illustrated examples of issues and solutions that have been adopted. It also discusses the challenges with trying to upgrade non-structural elements within existing operational buildings including for example, congestion issues and practicalities of access. The paper concludes with ideas on possible ways to improve the seismic performance of non-structural elements within the New Zealand environment and regulatory regimen from both design and construction perspectives.