Earthquake

[repton_infinity]

So, there's been a big earthquake in Christchurch. I have told people, in the past: "When early settlers came to NZ, some built in brick and some in wood. Then big earthquakes knocked all the brick buildings down, but the wooden ones stayed up, and so after that they built only in wood. And so today, practically all NZ houses are wooden."

The

Comments

[exiledinpn]

The brick stuff is all old; there hasn't been a serious earthquake in Chch for about a century, and it was either built shortly afterwards, or survived the first one.

[jwm]

Indeed. Brick facades fell off, brick fences fell over and so forth. The CBD had a lot of old brick buildings that are in a bad way, while other parts of the city around the Avon and towards the sea suffered from liquefaction of the soil, so they're a mess, too.

Riccarton and Addington hardly had any damage at all; interesting because there's a place in Addington called The Mill which is a big old brick mill turned into flats and later condemned as an earthquake hazard. Some friend who lived there drove past to check it out, and it looks fine.

So its entirely possible that the old brick stuff just got lucky the last time there was a big enough earthquake in chch. Generally, it pre-dates the Napier quake of '31.

[mashugenah]

Brick is relatively common. About 15-20% of houses that come through our office have at least some brick. The difference is that it's a single-layer veneer tacked onto the outside of the house as a cladding. In an earthquake the expectation is that it gets badly knocked about, but doesn't compromise the gravity structure of the house.

The design loads for CHCH buildings are notably lower than Wellington, but still high enough that brick doesn't seem like a good idea.