Wednesday, September 15, 2010

New Zealand Earthquake - Interior Damage


"I cannot understand why a new council building is put out of action by an earthquake and an art gallery, surrounded by glass is used as the Civil Defence headquarters," Anderton said.

Ok, kiddies, this earthquake may tell us to pay more attention to interior damage! I really think a building should remain functional at 10 cm/s PGV. The building codes pay no attention to this, since they are just interested in preventing collapse, and allowing a safe exit. Every time I go to the cottage, I watch this office building going up. It hasn't go a shred of shear stiffness! The steel looks like a house of cards! I'm blaming 'limit state' design on this, since the old methods always forced a shear wall. This building will never collapse, but the inside will be thrown up against the wall! I shudder to think what the fundamental frequency is, with the building fully loaded. Oh well, we'll find out about this in the next earthquake!


Anonymous said...

Question for you - Most of the damage in New Zealand seams to be old brick walls. With our modern construction of tieing the bricks to the wooden frame of a house with metal straps, would our brick veneer hold up better. Does the rigid brick in conjunction with a flexible wooden frame make our houses stronger or does the weight factor of the brick negate any shear strength advantage?

Harold Asmis said...

Well-mortared brick has good shear strength. I would not expect any damage to the brick veneer of a modern frame house, up to the point of total collapse.

Now, the chimney is a different matter. And the interior.

Anonymous said...

Thanks for the answer. I guess the next question is - would your mag 7 scenario for Hamilton collapse a modern wood framed brick veneered house?????

Harold Asmis said...

Even on a swamp, that house wouldn't totally collapse. It's the interior things that would injure someone. They have these 3 story homes on the major sag pond of the Hamilton fault. I'm sure things and people will get thrown.