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...2 inches for such a tall building is such tiny angle If it sinks does this mean the first floor is slightly below the street level ..it probably means that the areas around the door and where the concete meets the street are cracked
"To cut costs, Millennium did not drill piles to bedrock." What are the implications for earthquake safety?
My house is on a steep hill, and Seattle has a reputation for hills sliding away under heavy rain. Before building it, I hired 3 separate geologists to evaluate the site. After digging holes, they said the site was sitting on "glacial till", which is clay that was compacted by about a mile of ice, and said there was nothing to worry about. Paying them was worth it for the peace of mind. (Turns out the till was so har…
Loving your attitude. I often feel like with a lot of building (big and small) there is insufficient evaluation of site factors. For example: Is there a hill above the site? THAT needs to be evaluated (sometimes they do, sometimes they don't). Is the site on a traditional floodplain? If so what actions have been taken to redirect the water flow? Does the system have the capacity to move the water away? Is the site it…
My most expensive mistake was not having a geothermal heading system installed when the yard was all dug up anyway. I could have had it essentially for free, and save 30% on the heating bill.
My house is on a steep hill, and Seattle has a reputation for hills sliding away under heavy rain. Before building it, I hired 3 separate geologists to evaluate the site. After digging holes, they said the site was sitting on "glacial till", which is clay that was compacted by about a mile of ice, and said there was nothing to worry about. Paying them was worth it for the peace of mind. (Turns out the till was so har…
One of the geologists told me a simple way to judge the slide risk. Look at the tree trunks. If tree trunks are leaning, or are curved, that indicates the ground under them is shifting.
The other thing to look at is fence posts if they are old.
The article doesn't talk about the how this practically affects the entrances to the building. Do the doors have to be adjusted for such a drastic sinkage, or are buildings somehow designed so this isn't noticeable to the public?
Nuff said.
Nuff said.
My house is on a steep hill, and Seattle has a reputation for hills sliding away under heavy rain. Before building it, I hired 3 separate geologists to evaluate the site. After digging holes, they said the site was sitting on "glacial till", which is clay that was compacted by about a mile of ice, and said there was nothing to worry about. Paying them was worth it for the peace of mind. (Turns out the till was so har…
I was told by a contractor that it's extremely common for houses to have shifted considerably, sometimes by several feet. Mine certainly has, though not nearly that bad.
Most of the houses are built on concrete foundation walls that go about 3 feet into the sand. Despite being unreinforced and using water-permeable cement, they've seemed to hold up reasonably well. It's usually the whole house that shifts and racks. Yet looking from the street you wouldn't expect that because all the houses abut each other, with only a few inches or none of space in-between. (Perhaps this has mitigated the problem somewhat, though.)
Despite being built entirely on giant sand dunes, the Richmond district is only "moderately" prone to liquefaction. And there wasn't much notable damage during the 1989 earthquake, AFAIK. I think (though cannot confirm) that similar foundation techniques were used as far back as 1905 and earlier, in the Richmond, Sunset, and elsewhere, and judging by their survival and continued use of the foundation techniques I'm not particularly worried. (While widespread building in the western half of the city didn't begin in earnest until about 1910'ish, there are hundreds of buildings many decades older randomly distributed, especially closer to the beaches.)
The bigger problem is that almost all houses in the western half of the city were built with so-called soft stories as the first floor--basically a giant open space supported almost entirely by the external walls. Interestingly, AFAIK this design came before the widespread introduction of cars. These days nearly all houses use that space as a garage, but I believe they were built as unfinished first floors intended to be finished as desired--e.g. workshop, additional family rooms, in-law apartments, etc--while keeping the initial purchase price low.
Earlier quoted context omitted.
How much would it have cost to dig down to bedrock, and pour a concrete foundation from the bedrock up to surface level? Between the amount of sand to be moved and the amount of concrete to be poured, it sounds like an enormous fortune; I guess that the relevant questions are whether the market could bear it and whether it would be cheaper than the rapidly-developing lawsuits. It may be that the building didn't make…
The real problem with digging down to bedrock is destablizing the building. Though there may be enough redundancy in the pilings to do it one at a time.