Plastic Hinges 5

[GalileoG]

I am having a hard time trying to understand exactly what or how a plastic hinge is formed during the seismic response of a structure. What exactly is a plastic hinge, why is it formed during dynamic (seismic activity) and where do they form? The texts that I possess explains it but I still have not completely grasped it. Thanks.

 

[frv]

I wasn't doubting youngstructural..

You just simply never hear about devastating earthquakes in New Zealand... but that may have more to do with how sparsely populated it is..

You always hear about earthquakes (significant ones, anyway) in Japan, Western US, Chile, Turkey, Mexico, Central America, Indonesia..

Of those countries I just mentioned, only Japan and the US have the research institutions and the capital to do significant research.. it's good to know about New Zealand, though..

 

[hokie66]

Yes, a lot of people in the US have never even heard of New Zealand. Or Australia, until recently, and then only because of a few celebrities from here.

The city of Napier on the east coast of New Zealand has the largest concentrated collection of Art Deco buildings in the world because an earthquake in 1931 destroyed the city, and the whole business district was rebuilt in that style.

 

[frv]

There are a lot of things the "average" US citizen would not know nor care to learn, but that's a discussion for another forum or, preferably, a bar..

I'm not sure if you've lumped me into that category. I assure you my interests extend beyond my immediate surroundings. Never having heard of a major earthquake in New Zealand is NOT the same as never having heard of New Zealand, their people or their culture.

This is not a matter of arrogance, ethnocentric or otherwise, nor is it a matter of "criminal" ignorance..

I'll bet you the majority of people on this forum, many of whom are very bright (at least judging form some very lucid and insightful posts), and many of whom practice in other English-speaking parts of the world, would find themselves surprised, as I was, the New Zealand is the place to go to practice seismic design... (anybody care to chime in?)

Again.. and for the last time.. I'm not disputing it.. I simply found myself thinking .. "hmm.. I did not know that.." when I read the post..

 

[youngstructural]

Alright, I feel that I have to chime in again...

frv: Those lucid and insightful posts as often as not come from you; So I certainly wasn't thinking you were "a [typical] arrogant American". You might be surprised to find that I actually don't think the typical American is arrogant. I think the typical American comes from such a large, diverse and busy country that they simply don't see the forest for the trees that immediately surround them. Again, as you've pointed out regarding your knowledge of New Zealand, there is a difference.

Secondly, let's not let this degrade any further. I want to take responsibility for the degrading that has occurred. Meaculpa. However, please help me move forward and get back to the technical point au courant: Plastic hinging under Seismic loading.

I do have to say that it'll be quite a treat to point out to my own little Kiwi at home tonight that an Aussie came to the defence of "our" countries technical prowess.... DESPITE the fact that such defence was not necessary in the first place as it was all a big misunderstanding mostly of my making.

Anybody want to discuss their views of the finer points of bar development in a plastic hinge zone (such as never, never, never do it, ever?), or hooking into a column in a ductile seismic frame?

Respectfully to all the worthy commentators,
And in the hopes that Structuralnerd hasn't been scared off and might accept some of my literature recommendations,

YS

P.S. Since it's Friday for Hokie66 and I, have a great week-end all. And if you're ever in Christchurch there Hokie66, drop by the Connell Wagner offices and say hello. Beer's on me.

P.P.S. I wonder if I have violated the site policies enough in one day to get my hand slapped or post removed. Hopefully not, as there is a value to seeing deteriorating threads come right! *hint hint*

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[hokie66]

frv and youngstructural,

I agree. Truce! But just to clarify, I have some standing in being able to bag Americans (not you, frv) for ignorance of the wide world, because I am one. I just happen to have married an Aussie girl and have lived here for 26 years. Now, like most Aussies, I tend to complain about all manner of things that occur in the rest of the world, including how many Kiwis are coming to Oz.

That's a decent company you work for, ys. Small world indeed. At the risk of further offending the site police, I retired from CW a few years ago, but still get involved from time to time when the office is busy.

Since you are shouting, I might join you in a bottle of that plonk NZ is becoming known for. As well as earthquakes, that is.

 

[youngstructural]

Ah, a CW man; well that would explain the excellence of your posts... (Now I'm sure a moderator's going to e-mail me).

The wine certainly is good; Moved here for the Engineering, stayed for the woman (singular) and wine. Plus the job's not half bad. We could actually use a hand at the moment. Saturday morning and I'm at my desk with a new job on the go. Can't complain though as I really do love the work.

Do drop in if you're in town. And wine it is.

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[dgkhan]

First of all, I have worked in USA and outside USA too. I am very keen on seismic issues as most of the career I could get away with writing zone 1 .. 4 on dwgs. Not anymore. But I never knew NZ is top most. I do not want to challenge that. BUT can I get facts here. Statistics here. How?

 

[youngstructural]

Unfortunately there really isn't any way to prove it one way or another... It's just an opinion. It also has alot to do with what KIND of seismic design you believe in; There are numerous schools of thought and no one is 100% right.

I do feel confident that I can say that if you believe in Capacity Design, then New Zealand is number one. They invented it, they have pursued research focussing on it and the issues involved for around 40 years and they have implimented it widely throught the country.

If you're a base isolation fan, I think you've got to look at Europe or the states. For active anti-seismic measures (such as active damping or energy dissipation) I'm pretty sure Japan is your ticket.

I prefer and strongly believe in Capacity Design because of how straight forward it is, how robust a system it is, and how it's essentially just our regular Structural Engineering knowledge applied with a view to ensuring certain areas experience the yielding that is inevitable anyways. Capacity Design does not fail if an Earthquake's energy output (or input to the structure) is higher than anticipated; The structure will simply drift more, but still not collapse. It's far more robust than most other design measures for Earthquakes.

dgkhan: You say you're very keen on seismic issues, and I am not doubting that. I am very curious: Where do you practice and what theory is commonly applied there? What theory do you apply?

Regards,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[Qshake]

One need only be keen on learning about earthquake engineering and to take specific note when crossing the writings of Park and Paulay not to mention those of Freider Seible, possibly the most successful research professor of seismic related work in the developed world.

Those are all examples of New Zealanders dedicated to the understanding of and teaching earthquake engineering.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[youngstructural]

I recognize Dr. Seible's name having read and appreciated some of his work, but I didn't think he was a Kiwi.... I had actually thought he was German. I do believe he did one of his graduate degrees in Canada with one of my Professors (at Calgary).

Would be keen to hear if you're sure he's a Kiwi Qshake!

In any case, I think there are at least a few people around who share my belief that NZ is a great place to learn about what to do when the earth shakes...

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...