Every once in a while there's an earthquake somewhere that does some decent damage. Recently it happened in Bam Iraq, and the city wasn't structurally prepared. 35,000 or so died.
Satellite image of Bam after Quake.
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A few more mud building pics
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Iran's quake: Nothing 'natural' about this disaster
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"The earthquake in Bam reached a magnitude of 6.6 and killed more than
20,000; yet an earthquake in San Francisco in 1989 that measured 7.1 and caused $10 billion worth of damage, resulted in only 63 deaths."
Buildings should be built to withstand a reasonable earthquake, even in an area where such events are unlikely.
One of the newer safeguarding methods is rapid prediction and warning. Apparently, even in an area very near the earthquake-producing fault, you can get perhaps a minute - it depends - of warning. In this time, trains can stop, elevators can make it to the nearest floor, gas lines could be shut off, etc.
But the main method of structural preparedness is designing to accommodate lateral forces.
What are the better methods to design and build for an earthquake?
There is not just one technology providing safer structures, but those avaible is all High-tech , and to restore structures to face what would happen in the future , you must count in more than one technology.
Also you can not just restore ,you need to restore for the future.
Enforcement of building codes helps too. When an earthquake hit Turkey in 1999, the damage was far more widespread than it should have been. The reason was that while the building codes on the books would have helped prevent much of the damage, they simply weren't being enforced. I'd bet money that the same was true in Bam Iran.
A good book about this is PEACE OF MIND IN EARTHQUAKE COUNTRY, endorsed by Charles Richter, of Richter Scale fam, himself. But it's important to get the second edition because it was written after the LA quake and was revised to say that stucco and shiplap wooden sheathing require plywood backing, where the previous edition said that welded wire lath and stucco was adequate for moderate quakes.
Many areas have inadequate or no earthquake codes, including parts of the U.S. Southeast, where one of the worst quakes ever in the U.S. hit in the 19th century. Homes should be built on one-piece foundations, not on individual piers, and wooden homes bolted to it every 4 feet, including within 1 foot of each corner. All structural lumber should be tied together with metal brackets, like StrongTies, and covered with 3/8" or thicker plywood nailed all along the edge and center studs. I don't know if OSP waferboard is an acceptable substitute. Masonry block construction is probably not a good idea because it really needs reinforcement about every 12", horiziontally and vertically, and every hollow has to be filled with grout, adding substantially to the cost. Poured, sprayed, or tilt-up masonry is probably cheaper and much stronger.
Many of my relatives are in the construction business in Japan and are paranoid about quakes, so even here in southern Arizona our masonry house was reinforced with steel I-beams in the garage, and our current home was built on shock absorbers.
If you build out of unreinforced mud brick, you'll get collapse. San Fran, OTOH, has some of the most advanced earthquake designs around and the design standards are upgraded with every major earthquake. Iran is relatively poor, California is rich - go figure.
If you design for progressive collapse, common in many jurisdictions, you'll satisfy many of the requirements for basic earthquake protection. This should be adequate in areas where earthquake risk is quite low.
And you'd be wrong some of the time. Earthquakes are assumed by most folks to generate lateral forces, however, they can generate considerable vertical and torsional forces as well. You have to design for all these things. Take a look at the collapse of the Olive View Medical Center in San Fernando in 1971 - all four corners of the building moved in a different direction - it collapsed in torsion (the ultimate flaw was incorrectly placed reinforcement in the concrete columns - the spiral containment wasn't run thru the floors but stopped short). (Actually the building was L-shaped in plan IIRC, so take "corners" figuratively).
Just go to the best building codes - start with California's.
I visited Tehran on business a couple of times just before the Shah's got overthrown, it probably was 1978. It was quite an interesting place with a significant dichotomy between the haves and have-nots. Manpower made up for a lack of construction equipment in a noticable way.
Last week's earthquake reminded me of something I observed there and never forgot. They were building what looked like a 5 or maybe 6 story steel framed office building right across from my hotel and I could look out my room windows and watch the progress.
The first thing which stuck me was that the steel skeleton was noticable thinner than my recollection of similar constructions over here. I immediately thought "earthquake".
The work force on that building had some ways of doing things which I'd never seen back home. A large number of the workers "slept on the job" overnight, by curling up in bedrolls on the ground floor. I used to see then preparing their meals there in the morning and evening.
But one scene I never forgot was watching them move a pile of bricks from ground level to the third floor, before the walls went on. OSHA would have loved it.
A guy on the ground was bent over the supply pile picking up one brick at a time and throwing it upward without straightening up or looking overhead. A worker on the second floor was leaning out by hanging onto an upright with one hand, catching the bricks with his free hand, and flipping them up to a guy similarly stationed on the third floor, who cought them and flung them onto a pile on the floor slab.
No hard hats of course, and I suppose those guys had some sort of signal they'd yell out if one of them missed a catch.
Come to think of it what they were doing wasn't too far removed from what I'd read used to be common practice here when steel building skeletons were fastened together with rivets. One guy would heat rivets red hot in a portable furnace and then grab them with tongs and toss them one by one to the riveter, who cought them in a bucket, stuck them through the holes in the parts to be joined and headed them over before they cooled down.
The other qua> Every once in a while there's an earthquake somewhere that does some
I've seen an old unreinforced standstone building get cut off of it's footings and have 450 new rubber pads installed underneath it. Each pad was made up of alternating layers of rubber (recycled tired) and steel plates. The whole foundation was "squishy." It was pretty cool to see the building "floating" over the existing foundation (only from the crawlspace below).
............ ...First of all, as you cannot control the Nature, none can control its phenomenon neither. Therefore, as any earthquake is a just among those phenomenal exteriorization along any concentration, one way or an other, of an energy along its faisibility and need of an adequate utility. Something, however, none and nothing would be having any adequate ability to determine along a space time.
Therefore, for the time being, none as nothing can determine its interference, it remains only to prevent along a faster destruction as along a global destruction along the appearance of an any earthquake, whether it does remains as still any bad things for some, is a good things for others, as this a part of the human nature.
However, when we do turn around to construction industry, an advancement of the construction would as should a definitely as a systematically apply. Ultimately, out of missing, that in the case of an earthquake the mouvement of a destruction is a definitely along the third dimension, and this a part of the power and the force of the nature, definitely as a matter a fact!!!!!!!!!!!!!!!!!............ ...
"Ahmed Ouahi, Architect" skrev i en meddelelse news:btesiv$3tf$ snipped-for-privacy@nyytiset.pp.htv.fi...
, the mouvement
True, earthquake run in waves so an interconnected assembly framewoork will not be affected by single frames movement. If a structure is huge enough covering a lot of spaces, then a framework structure will follow the earthquake waves surviving by not resisting the forces. Such matters shuld be build-in with computers, but I guess these are (computers) better for lotto.
I rather deal with tomorrow , than making today into studying estoday, ------ I se no reson why a 3D-H can't act as supporting structures ,holding the restored , but it will _not be Lego style ;))
.......... ...The most true is that you do still and you would definitely and forever remain the most stupid on the shell of the earth. When you do, furthermore, allow your ignorance to provide you with such stupidity, definitely as a matter a fact.
As you do know a shit how anything, whether everything the way and how it does run, out of a scannig any stupid publicity and let the computer to show it to you differently, something you do destroy definitely!!!!!!!!!!!!......... ...
............ ...First of all, as you cannot control the Nature, none can control its phenomenon neither. Therefore, as any earthquake is a just among those phenomenal exteriorization along any concentration, one way or an other, of an energy along its faisibility and need of an adequate utility. Something, however, none and nothing would be having any adequate ability to determine along a space time.
Therefore, for the time being, none as nothing can determine its interference, it remains only to prevent along a faster destruction as along a global destruction along the appearance of an any earthquake, whether it does remains as still any bad things for some, is a good things for others, as this a part of the human nature.
However, when we do turn around to construction industry, an advancement of the construction would as should a definitely as a systematically apply. Ultimately, out of missing, that in the case of an earthquake the mouvement of a destruction is a definitely along the third dimension, and this a part of the power and the force of the nature, definitely as a matter a fact!!!!!!!!!!!!!!!!!............ ...
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