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Earthquake near DC
3

Earthquake near DC

Earthquake near DC

(OP)
5.8 mag earthquake on the east coast.

RE: Earthquake near DC

Latest reports have people reporting the earthquake from Mass and CT and NY all the way down to the Carolina's.   

The North Anna nuclear plants near the epicenter are reported shutdown.    Probably automatically.   5.5 is really pretty minor to industrial facilities, but structural and residential framing and masonry, painting, trim, plaster over lathe, and drywall cracking will likely be very large.   

 

RE: Earthquake near DC

This event makes my point in another forum string here that I made a few days ago - regarding eliminating the seismic requirement in Florida.

 

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

Why did you do it, Mike?  Pretty drastic way to make your point.

RE: Earthquake near DC

msquared - lets not get ahead of ourselves, I didn't feel any earthquake down here in the Sunshine State

RE: Earthquake near DC

@ash This quake was not on the real problem fault the New Madrid, that sure how much of an issue but I would not rule it out because of this one.

RE: Earthquake near DC

Finally got to experience a quake; I work in NYC.  In 1985 we had a 4.5 about 25 miles north NYC but I was in West Virginia.

Interesting feeling.  

RE: Earthquake near DC

I love this!!:  

The Hill is reporting that the Park Service is stating there is no serious damage to any of D.C.'s national monuments:

U.S. Park Police in Washington made an initial survey of the city's monuments after a 5.9 magnitude earthquake and found no serious damage.

According to The Washington Post, the Park Police checked the monuments by helicopter shortly after the earthquake on Tuesday.


Yep - that is the proper procedure to check out a structure after an earthquake - get in the chopper with your binoculars and check it out!


 

RE: Earthquake near DC

What gets me is that they evacuaated ... the PENTAGON ... after all that retrofitting over the last few years.  God help us if the pentagon can't take a little 5.8.

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

Oh, and ash060...   Yea, I was a little off aim with my haarp.

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

People are making a big deal about this 5.8 earthquake, but it doesn't sound like it caused any real structural damage.  I practice in Louisiana where the largest we've ever had is 4.2, and yet seismic can still actually govern over wind in hurricane country.

Something is wrong with that.

RE: Earthquake near DC

Not for a consrete structure with a low wind exposure in one direction...

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

Or a concrete bridge...

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

hokie66,
Wow...they actually gave credit to "structural engineers" instead of using the term architect.

Not sure how a crack at the very tip top would be seismically induced but you never know.  I'd expect cracks closer to the base, or maybe at mid-height.

 

RE: Earthquake near DC

Having lived thru a 6.8, 6.4 and several 5+ earthquakes, looks like they are making a very big deal out of 5.8.
 

RE: Earthquake near DC

The media is making a big deal about it because it's a rare occurrence. The 1985 EQ in NYS, was only a 4 (the epicenter was near a nuclear reactor)but it led to the requirement for seismic design in NY.

For years the seismic gurus were saying that most of the east coast would never experience anything higher than the mid-5's. Today the sky-is-falling crowd in NY is predicting a 7.0 is going to hit NYC.

Last night when I was leaving work, some people (not engineers) on the elevator were saying "we have to do something to stop these earthquakes."

RE: Earthquake near DC

@bridgebuster -  I got a laugh out of that quote.

RE: Earthquake near DC

I heard a "news" report this morning where they found some professor and got him to say that New York City will crumble when the big one hits since the buildings were not designed to sway like California buildings are.  

I guess they couldn't find an engineer who would say what they wanted to report- so they went to academia.

For the area impacted- 5.8 is obviously big (in California- they don't put down their coffee until a minimum 6.0), but I would bet that for 95% of the buildings, the seismic load didn't approach the wind load the buildings were designed for. The primary buildings where I would expect to see structural damage to would consist of un-reinforced brick walls that were not designed to current codes or buildings that were not constructed properly.   

  

RE: Earthquake near DC

kawkaz - In the late 90's I went to a conference about the seismic requirements for NYC, and one speaker said exactly what you said about wind loads controlling and un-reinforced masonry buildings being more of a concern.

RE: Earthquake near DC

We felt it up here in Ottawa Canada, shook the stuff on desks, paintings hanging on walls rattled, etc ... for about 20 secs, mind you the buildings 'floating'  on top of 150 feet of Lake Champlain marine clay then finally bedrock.
Despite all the seismic reinvigoration that's gone on over the last 6 years for us, we're still having the most damage and problems with wind, winds we aren't required to design for but are getting with increased frequency and increased speed.

RE: Earthquake near DC

The media is making a "BIG DEAL" about this little earthquake because it happened underneath their very own shaking little bottoms.   If the same shaking happened outside of NYC and Washington DC, "they" the national media would not care.   

Compare this "evacuation" of federal buildings and mass "leave work early to check on the family" quasi-hysteria in the media to a real 6.0 earthquake in say, Alaska or Washington state or Oregon.   Or Peru.      

RE: Earthquake near DC

JAE:

It depends on the harmonic it saw, but I agree - I thought of the whiplash effect here, and the fact that the structure is over 120 years old since completed, and 230 years since the conceptual design.  Not too many computers back then.   

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

I'd be WAY more concerned with Irene then a tremor of that magnitude if I lived in the NE right now. Lucky for me it just means I will be doing some surfing here in Florida in the upcoming days...

Mike- as to your point and that other string on seismic design in Florida, I thought about that too. Since the largest seismic event ever in Florida is estimated in the lower "3s", and this one was a 5.8 and did not cause much in the way of serious structural damage in an area with much older structures (that I have seen so far), I would be further convinced our state is just fine in not requiring seismic design since we have 100-150mph wind design requirements...

But who knows, maybe the geophysicists have missed something and we will get a big one in our lifetime!

 

RE: Earthquake near DC

2
We had a about a 4.2 here in St. Louis about two-three years ago at 2:00 am.

Woke my a$$ up.  Not my wife.

Told her our bed hadn't moved that much in twenty years!!  

I still haven't gotten all the teeth fixed!!

RE: Earthquake near DC

a2mfk:

The thing that worries me about the Florida situation is the proximity geologically to Haiti and what happened there.  There are some pretty serious fault lines running east-west there with a long history.  That coupled with the fact that we do not know it all, as you said, worries me.  Maybe not for a "big one" as we visualize for the west coast, but more than bargained for in Florida for the concrete structures there.  That's my concern.

Mike McCann
MMC Engineering

 

RE: Earthquake near DC

Quote:

Mike- as to your point and that other string on seismic design in Florida, I thought about that too. Since the largest seismic event ever in Florida is estimated in the lower "3s", and this one was a 5.8 and did not cause much in the way of serious structural damage in an area with much older structures (that I have seen so far), I would be further convinced our state is just fine in not requiring seismic design since we have 100-150mph wind design requirements...

What was the max earthquake in Florida?

http://earthquake.usgs.gov/earthquakes/states/florida/florida_eq_history.php

The link about doesn't say the magnitudes but the highest on the modified mercalli scale is MMVI, which would correspond to a magnitude of about 4.3.



 

RE: Earthquake near DC

Here in Northern NJ the PGA was about 1%. At the epicenter it was 30%. We design in NJ for around 40% of PGA. Trains and Tandems rumbling are about 0.5% +/-

RE: Earthquake near DC

This link has a photo of the crack on the top area of the Washington monument:

Wash Monument Crack

 

RE: Earthquake near DC

JAE,

is this really true? this seems to be at the top area of the monument. and it seems that the crack was exaggerated.

I was expecting that for a free standing structure the crack should be major at the bottom.

Anyway, I was born in the land where 8-9.0 magnitude is possible.

As observed, for some countries..earthquake magnitude never goes down. year 90's it was magnitude 4-5 only and that is the highest. Nowadays, no more of these magnitude yet this is the lowest.

This must have something to do with the last days.

Regards,
E104909

 

RE: Earthquake near DC

(OP)
If they shut down the Washington Monument for that crack they need to start shutting down all the bridges, all the government buildings, all the airports, all the...

My initial response is too many lawyers, but I'd conclude with too much ignorance.  There is too much money/prestige to be gained by scaring people and no consequences for false alarms.  Land of individualism - the rugged have all left.

RE: Earthquake near DC

True Story:

I'm based out of the SE (Carolinas) and my firm had recently finished construction of a large (for this area) 15 story tower for a client in NC. Well, this EQ hits Mineral, VA and our client is suddenly very aware that Earthquakes do, in fact, happen (who knew right?). Anyway, for the past two weeks I've been doing some THA stuff and comparing the Mineral, VA EQ to essentially it's equivalent EQ in NC.

Results? I was actually surprised to find there are some parts of the design response spectrum [ASCE 7-05] that were exceeded by the Mineral, VA EQ. We saw peaks exceed the spectrum for a natural period of .6-.8 seconds and again at 1.1 to 1.3 seconds, the later being much less pronounced(Our data was obtained from the CERI center out of Memphis).

With the realization that more people than just Engineers sit on the Building Codes, anyone got the over/under on the Seismic requirements on the East Coast increasing in the next few code cycles? I know which way I'm betting.

-HF

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