Earthquake and fire resistance construction 1

[TechBear]

I've been doing some research on the best construction technique for earthquake and wildfire prone areas, like california. I come from Italy where the standard construction is concrete rebar. earthquakes go up to 7.3 richter over there. I noticed the standard construction in CA is wood frame, but that's quite flammable. I saw that iconic picture of the multistory mansion which survived the oakland fire, apparently it was covered with stucco, which provides some fire resistance to the wood frame. I know about other basic proofing from wildfires (mesh or shutters over any vents, tempered glass, non-flammable buffer zone around the house...).

every time I mention concrete rebar the standard response is that it is too dangerous in CA because of earthquakes. yet I know that you can make concrete rebar more earthquake proof, for example by decreasing the distance between the metal joints in the metal frame before you pour the concrete (sorry I'm not familiar with the american technical jargon). having read that concrete rebar can resist several hundred degrees before structural failure (about 400° C I think), it should be more fire resistant than stucco+wood frame.

what do you think is the best earthquake and fire resistant construction technique? I'm trying to understand whether the expert consensus is, as it seems to me that the people I talked to so far are prejudiced against concrete rebar, maybe because many contractors may not be too familiar with it.

in case one of you is an expert in fireproof construction, I've also tried to look at air temperatures around forest wild fires, to estimate what temperature the external wall of a house at about 50-100 ft from a forest fire would be, but found very little literature on the subject, most just theoretical models of temperatures within the actual wild fire.

 

[WARose]

As far as construction goes, properly detailed (i.e. "special") steel & concrete moment frames tend to be the best at handling earthquake forces. (In terms of dissipating energy.) But it's rare to see those types of frames used in home construction in the US. Most of the time, we use wood.

As far as fire resistance goes (for protection against wild fires), some techniques include fireproof roofing tile, masonry/brick exterior, and limiting/eliminating flammable exterior materials. Some of that is non-structural. For example: limiting the amount of brush near and around your house is important. Looking at some of those fires that burned those houses out in California: they had bushes right up under the eaves of the roof. They also had lots of leaves, rolls of garden hoses, etc right next to the exterior as well. Even if you have the most fire proof frame in the world.....that doesn't mean the rest of the house cannot burn.

 

[atrizzy]

Following WARose's statement, wood panel shear walls have been shown to resist large seismic forces rather well. Millions of nails bending and creaking do eat up a lot of seismic energy, it tunrs out. Up in BC Canada we now permit up to 6 stories of wood framing and panel shear wall construction, providing that the shear walls are continuous for the height of the building. Hold-down forces can become excessive in these situations so it's important to have long segments of walls as well, but it is done.