Rare Example of Instrumented Bldg Damaged During During An Earthquake
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From: Bret Cahill on 22 Jun 2010 14:58 > > > http://www.usc.edu/dept/civil_eng/Earthquake_eng/Selected_Publ/PDF/IC.... > > > > Two interesting questions: > > > > Why aren't they instrumenting bldgs today with relatively cheap MEM > > > accelerometers? > > > > Who decided to spend the equivalent of 200K on force balance > > > accelerometers and other electronics 40 years ago for a public bldg > > > 1) Parkfield, CA > > 2) Caltech's Millikan Library. > > > Every time Southern California shakes a Caltech Earth Sciences grad > > student writes his PhD. > > In the 1970's, there was a lot of concern over the > so-called Palmdale Bulge. Trouble is, it now appears > the bulge never existed. > > http://www.kilty.com/bulge.htm- Hide quoted text - A good article underscoring the need for precision distance measurements of fault lines. Some article said frequency drops as a reinforced concrete structure is degraded -- kind of like burning out resistors in circuit. Bret Cahill
From: Bret Cahill on 22 Jun 2010 23:38
> http://www.usc.edu/dept/civil_eng/Earthquake_eng/Selected_Publ/PDF/IC... > > Two interesting questions: > > Why aren't they instrumenting bldgs today with relatively cheap MEM > accelerometers? > > Who decided to spend the equivalent of 200K on force balance > accelerometers and other electronics 40 years ago for a public bldg > out in the desert? Someone in coastal California pretty much knew the building was coming down. "Hey, the hayseeds out in Imperial Valley just build this county services bldg. that cannot survive a 6.0. WHAT AN OPPORTUNITY! We'll instrument it and find out what happens to the frequency response of RC structures during an earthquake . . ." Bret Cahill |