Let's say half of them. And let's say that at least two were over 4.0 magnitude. Where there's a 4.0 there's a 5 lurking and a 5.3 waiting to shock the living daylights out of everyone. Seattle is definitely more subject to seismic activity because it sits on the ring of fire, but they hadn't had a bad quake in forever and the oldest inner-city infrastructure was mostly un-reinforced. In 2001 they had a 6.1 that lasted for something like 45-50 seconds and the damage was profound. My point is that you're gonna have one here and there and all it takes is a 3.5 in an old unreinforced building to blow everything up. I'm not advocating we brace everything everywhere or retrofit where it hasn't been mandated already, I'm just saying that generalizing isn't an accurate MO.
But here's an idea for those allergic to bracing: if you're in one of these areas that's active, but where magnitudes are generally sub-3.0, why not observe flexibility and restrain the branches? SML -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Todd - Work Sent: Friday, February 21, 2014 2:05 PM To: [email protected] Subject: Re: seismic bracing calcs Steve, I have seen that list. If you look closely, most of those readings are from the eastern provinces of Canada. There are some in CT, but most are in the 1.0 to 2.0 range (see Moodus Noises). There have been some dish rattlers in the past, but not too many. The 1755 quake was estimated to be in the 6.0 range. The majority of the more significant ones have been centered in NH. FYI, one of the quakes noted on 11/29/13 was located within 1000 ft of a church I did several years back. No damage. As far as the last paragraph, I will leave that alone. As a Pats fan (and also have done a fair amount of work for Bob Kraft's companies), I hope they have learned to get a good receiver and finally boost the defense. Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT www.fpdc.com 860-535-2080 (ofc) > On Feb 21, 2014, at 4:33 PM, "Steve Leyton" <[email protected]> wrote: > > That's what you think. Go here: > http://aki.bc.edu/cgi-bin/NESN/recent_events.pl > > Most recent temblors in New England were last week. Not big ones, but > you have them all the time. This feeds into what I said about changing > times: those maps in the annexes of older NFPA 13 editions are obsolete. > Throw them away. > > There was also a pretty severe jolt on Jan 18 that was thought to be a > seismic event but turned out to be about 1.3 million people all > sitting down at the same time when the clock ran out on the Pats in > the AFC Championship game. > > Steve > > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > Todd - Work > Sent: Friday, February 21, 2014 1:21 PM > To: [email protected] > Subject: Re: seismic bracing calcs > > I think you also need to take into account regional differences. Some > areas, like Leytonland, have a lot of earthquakes and potential for > serious ones in the future. They need to be on top of that. The last > major earthquake in New England was in 1755 off the coast of MA. > Earthquake potential is not taken as seriously out here. You go to > places like TX and it is virtually non-existant. There isn't the > consistent demand on a national level. > > The only time in the last 10 years I have had a direct involvement > with a structural engineer in when one guy used all his mechanical > dead loads to support the solar panels and forgot about the 3 - 8" > mains directly underneath going to the ESFR systems (which somehow was > my fault). The mechanical engineer looks to see if we meet their spec, > the architect wants to make sure it looks pretty, the insurance > company reviews it for _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler .org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
