Residential foundations

The Canterbury earthquakes provided a demonstration of the effects that a major seismic event can have on building foundations when the ground is poor. As the primary connection between the ground and most buildings, foundations bore the brunt of the earthquake’s energy. Liquefaction, lateral spread and differential settlement damaged the foundations of a large number of properties.

However, while some foundations were badly damaged, others performed remarkably well under the same conditions. In residential properties in Christchurch, shallow slab foundations generally performed well, except where they were badly undermined by liquefaction, particularly when unreinforced, used brittle reinforcement mesh or were not tied to the perimeter foundations. Residential-type piled foundations with perimeter foundation walls also often performed well, and where damage did occur, it was relatively easy to fix.

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