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ZeroGravitas 3 months ago

Building to protect occupants and building to make the structure salvageable afterwards may be two different goals. Think crumple zones in cars.

Almondsetat 3 months ago | parent | next [-]

This is not a good analogy.

Crumple zones in cars exist under the assumption that they will not be occupied by humans. In a house, on the other hand, any place could have a person inside of it during an earthquake, meaning that basically the entire house would need to stand to avoid any human being hurt.

ZeroGravitas 3 months ago | parent | next [-]

I'm not an architect and don't live in an earthquake zone, but I was under the impression that wooden homes flex in earthquakes and if and when they do fall on you, do less damage than concrete homes which are stiff up until a point and then crack and fall.

So the human surviving may come at the cost of more houses collapsing.

onlypassingthru 3 months ago | parent [-]

Can personally confirm. Wooden houses do flex and often survive unscathed. The only major damage is usually due to any masonry attached to the house (see: chimney) or the house moving off of the foundation (see: before ties were in the building code).

wiredfool 3 months ago | parent | prev [-]

It absolutely happens in steel and concrete construction in earthquake loading, when loading past the smaller earthquakes.

Plastic/non-linear deformation is intended in shear panels of steel connections and the core of well confined concrete beams/columns. The idea is to provide a lot of energy damping due to the nonlinear nature of the f*D hysteresis curve. This works long enough for the earthquake to go away and the people to get out of the building, at which point, you need a new building but hopefully no one has died.

earnestinger 3 months ago | parent | prev | next [-]

Nice point. Still, in wast majority of cases, house keeps standing -> habitant survival chance goes up.

Cars being on the move, makes that distinction much much more relevant

hnaccount_rng 3 months ago | parent [-]

For inhabitant survival a sifficient goal is something like “remains structurally intact for ~30 minutes after the end of the earthquake”. Which is significantly leas than is required for staying habitable

earnestinger 3 months ago | parent [-]

Makes sense.

I was fixating on the opposition of goals in the car (if car doesn’t bend/deform, then death risk increases).

llm_trw 3 months ago | parent | prev [-]

Where is the crumple zone in the burned out buildings in California?

HPsquared 3 months ago | parent [-]

Evacuation. Hardly anyone died in these fires.

llm_trw 3 months ago | parent [-]

That's traffic lights, not crumple zones.