CHRISTCHURCH POST-EARTHQUAKE RECOVERY

The 2010-2011 Canterbury Earthquakes caused significant damage especially in the city of Christchurch. As a result,much of the infrastructure – vertical and horizontal - is being replaced. This presentation describes the process of the Christchurch recovery. The Christchurch recovery only occurred the way it did because of the infrastructure, laws, culture, relationships, and relative costs before, as well as immediately after, the earthquakes. Christchurch had a mix of old and new structures of different sizes and heights. Most multi-storey structures were of reinforced concrete. However, the last two constructed before the earthquakes were of structural steel. Factors influencing the rebuild were the “performance-based” building standard, the wide uptake of insurance, the relatively low cost of structural steel, and the availability of new structural systems, (including low-damage systems, and lightweight economical long-span cold-formed floors (Figure 1-a). The most significant shaking event affecting the city of Christchurch occurred on February 10, 2011. The shaking intensity was greater than twice the design level explicitly considered in current standards. There were soil issues,including slides, slips and extensive liquefaction. Some older buildings collapsed, as did a couple of poor newer structures. The majority of older buildings and many newer buildings remained standing but were damaged and were pulled down. There was a perception that even well-designed concrete structures performed badly, as repair was difficult. On the other hand, the few damaged steel buildings within the city were repaired rapidly. Immediately after the earthquake, decisions were made affecting the later recovery. These included changes to design shaking levels in Christchurch, stair overlaps, ratchetting, and inelastic torsion, as well as others related specifically to reinforced concrete structures.

Keywords:

Canterbury , Earthquake , Organizations , Recovery , Rebuild