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asshat - snarg - 06-02-2005

in re the landslide in cali:

how do the builders get permits to build and is it possible to do so safely?
TIA

asshat - asshat - 06-02-2005

Every state is different regarding permits. In Texas, there is no permiting process or license for builders. There are builders associations that help control things. Other states (Fl for example) have very strict licensing for builders.

But, the problem in Laguna Beach appears to be more of an engineering problem, than a building problem. The engineers that designed the foundations for that area may have made a mistake. If the builders built them as they were engineered and they fail, it is not the builders mistake.

I don't know enough about what caused the problem to say. All I heard was that they were blaming it on unusually heavy spring rains.

If you have a soil condition that absorbs moisture, then that soil will continue to soak up water until it reaches its shear failure state. In other words, every different soil type has a different ability to absorb water. Once it reaches its shear failure, it will slide off at an angle (shear angle). If you have ever been driving down a highway and seen a slope beside the road that has failed, it is because it absorbed too much water and was at too steep of an angle to withstand the shear. If you see a sand pile (which sand absorbs no water and is always at its shear failure state), then the angle of the sides of the pile are its shear angle.

So, in Laguna, once that soil absorbed enough water, it failed in shear. If there were any homes built on the area within the shear angle failure zone, then they should have been engineered to withstand a failure. Evidently they were not.

asshat - Beaucephus - 06-02-2005

Man with all of those houses falling in the mudslides over the years there, I have just drawn one simple conclusion. That is to not build your house on the side of a fucking hill.

asshat - snarg - 06-02-2005

thanks, i agree, it is an engineering problem
in cali, the permit process is very rigorous, so someone probably cheated here

i just read another article that there was a large house under construction where the slide occurred

they are speculating that it was not being built properly, that the foundation did not reach bedrock, and that its failure caused the slide

asshat - asshat - 06-02-2005

snarg Wrote:thanks, i agree, it is an engineering problem
in cali, the permit process is very rigorous, so someone probably cheated here

i just read another article that there was a large house under construction where the slide occurred

they are speculating that it was not being built properly, that the foundation did not reach bedrock, and that its failure caused the slide


The speculation is probably right. If they had tied all of the foundations to bedrock, then the soil probably would not have failed because all of the drill shafts would have given it enough support to overcome the shear forces trying to bring it down. They should have probably also provided some type of dewatering system to insure that the soil saturation level never reached the critical stage. That would have been simple to do.