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Comment by epistasis | Hacker News Reader

In most of California, older low-rise buildings are by far the most dangerous buildings out there:

https://en.wikipedia.org/wiki/Soft_story_building

Rebuilding these as new modern apartments would make everyone a lot safer in case of an earthquake.

Also, we don't outlaw ways of life based on safety. For example, larger cities are far safer when it comes to fire deaths, than small towns, but we're not about to outlaw communities < 2,500 (see Figure 5):

https://www.nfpa.org/education-and-research/research/nfpa-re...

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Your linked Wikipedia article doesn't say that low-rise buildings are particularly dangerous. A "soft story" building is one that doesn't have good sheer strength due to missing sheer walls inside. It has nothing to do with being a low-rise or apartment building. As mentioned in the Wikipedia article, apartment buildings in Turkey were by far the most dangerous place to be during the 2023 earthquake.

Soft-story buildings are the most dangerous buildings in earthquakes in California, and they are all low-rise. In the article:

>Soft-story failure was responsible for nearly half of all homes that became uninhabitable in California's Loma Prieta earthquake of 1989 and was projected to cause severe damage and possible destruction of 160,000 homes in the event of a more significant earthquake in the San Francisco Bay Area

There are special warnings about soft-story buildings for home buyers, apartment renters, etc. in California. There are not such warnings for high-rises.

I don't know much about Turkey's buildings, but if there were less than 5 stories then they were all low-rise too. And I doubt that they would meet California code if they collapsed in a 7.8 earthquake.

Again, most buildings are low rise, especially old buildings, so of course most soft story buildings are low rise. But both low rise and high rise buildings can be soft story.

The reason buildings don’t collapse under shear (think side to side force like would be applied by strong wind or an earth quake) is in part because the interior walls offer shear strength. If you have too few interior walls, and you haven’t compensated via other mechanisms like stronger sheathing, then you risk catastrophic collapse. This is a risk in old construction where walls may have been removed or in cases where building weren’t constructed to appropriate standards. In Turkey, this was particularly bad because the use of concrete in floors and roofs results in more shear force.

The tl;dr is that this isn’t a low-rise vs. high-rise thing. It’s mostly an old vs. new thing.

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