Understanding structural selection decisions in Christchurch's reconstruction

After the Canterbury earthquakes, the city of Christchurch has changed from being a concrete city, with almost all buildings using concrete frames or walls to resist earthquake shaking, to a city with a variety of structural forms and a predominance of steel structures. This is a dramatic departure from past practice. Much of that activity is taking place at the heart of the city, in Christchurch's Central Business District (CBD). To quantify the extent of the shift in construction practice taking place there, and, more importantly, to identify some of the drivers that have influenced the decisions about the choice of structural material and specific structural systems, the authors have conducted a series of interviews with the structural designers of more than 60% of the post-earthquake buildings constructed to date in Christchurch's CBD, as well as with an architect, a project manager and a developer. Data was also collected from various sources (including Christchurch's City Council database), and quantitative information on structural forms and decision drivers has been assembled. Results show that the drivers are diverse and include costs, construction speed, perceptions of damage and of structural performance, tenants requirements, engineering culture, and other factors.