Structural Engineering: 2009-02-15

Saturday, February 21, 2009

Re: Remove from list

It's always "Clinton's fault"..... same ole shit...that's why GOP is out on their ass

-gm

On Sat, Feb 21, 2009 at 4:49 PM, Scott Maxwell <smaxwell@umich.edu> wrote:

To me, all "good politicians" (i.e. Those that get elected and continue to get re-elected) promise ice cream. The difference between a Republican and Democrat are the flavors of ice cream that they offer the people. And for those to the right of me that disagree, I point out the last 8 years, during which the Republicans controlled the whole kit and caboodle for much of the time. They were not to interested in feed and cleaning up after the cow either. Sure, they liked to give tax breaks (there is some nice ice cream for you), but they did not really cut spending overall one little bit. They did cut spending on things THEY don't like, but they also spent a crap load on things that THEY did like (like a money pit called Iraq). And now the Republicans want us to believe that they again are the party of "fiscal conservativism" and "fiscal responsibility". Sorry, no sale here.

And as to notion of blame for the whole mess that Republicans warned Democrats...maybe that is true. But, then if they "knew" about the problems, then why did they not do something about it. The notion of blaming ANYONE side for this mess is just plain stupid. Just as it was stupid to blame all the bad stuff about Katrina on Bush. I dislike Bush...I REALLY dislike Bush...I think he was the worst President we have ever had. But, he was also a major league scap goat on Katrina. His administrations response was certainly MUCH less than stellar and Bush himself did a few REALLY stupid things from a perception point of view, but for me, there is LOTS of blame to go around and that includes the people of New Orleans. As engineers, we should all know that they were playing with fire by living in what essentially amounted to a bowl that was below sea level on a coast that could get hit by a hurricane. It was purely a matter of time before New Orleans got toasted by direct hit by a significant hurricane.

But, then everyone likes their ice cream and don't think about the things needed to get the ice cream nor the potential consequences of eating the ice cream. We all like believe out ice cream never costs us anything, whether directly or indirectly.

And now I will return to shutting up about politics, eh, ice cream (not to mention it is making me hungry for some ice cream even though it is cold out and we just got some snow).

Regards,

Scott
Adrian, MI

On 2/21/09 12:15 PM, "ASLCSE@aol.com" <ASLCSE@aol.com> wrote:

In a message dated 2/21/2009 8:59:45 AM Pacific Standard Time, boyd@boydconsultinggroup.com writes:

How politicans get elected,

From a teacher in the Nashville area.

Who worries about "the cow" when it is all about the "Ice Cream?

The most eye-opening civics lesson I ever had was while teaching third grade this year.

The presidential election was heating up and some of the children showed an interest. I decided we would have an election for a class president. We would choose our nominees. They would make a campaign speech and the class would vote.

To simplify the process, candidates were nominated by other class members. We discussed what kinds of characteristics these students should have. We got many nominations and from those, Jamie and Olivia were picked to run for the top spot. The class had done a great job in their selections.

Both candidates were good kids. I thought Jamie might have an advantage because he got lots of parental support. I had never seen Olivia's mother.

The day arrived when they were to make their speeches Jamie went first. He had specific ideas about how to make our class a better place. He ended by promising to do his very best.

Everyone applauded. He sat down and Olivia came to the podium. Her speech was concise. She said, "If you will vote for me, I will give you ice cream." She sat down.

The class went wild. "Yes! Yes! We want ice cream." She surely could say more. She did not have to.

A discussion followed. How did she plan to pay for the ice cream? She wasn't sure.

Would her parents buy it or would the class pay for it? She didn't know.

The class really didn't care. All they were thinking about was ice cream.

Jamie was forgotten.

Olivia won by a landslide.

Every time Barack Obama opened his mouth he offered ice cream and fifty-two percent of the people reacted like nine year olds.

They want ice cream.

The other forty-eight percent of us know we're going to have to feed the cow and clean up the mess

Doug,
We do know that the "Republicans" warned the "Democrats" many times about the risky Subprime Loans. It started in the Clinton administration. If anyone want's to read the facts, let me know and I will send you a copy of the chronology.
Tony

A Good Credit Score is 700 or Above. See yours in just 2 easy steps! <http://pr.atwola.com/promoclk/100126575x1218822736x1201267884/aol?redir=http:%2F%2Fwww.freecreditreport.com%2Fpm%2Fdefault.aspx%3Fsc%3D668072%26hmpgID%3D62%26bcd%3DfebemailfooterNO62>

To me, all “good politicians” (i.e. Those that get elected and continue to get re-elected) promise ice cream. The difference between a Republican and Democrat are the flavors of ice cream that they offer the people. And for those to the right of me that disagree, I point out the last 8 years, during which the Republicans controlled the whole kit and caboodle for much of the time. They were not to interested in feed and cleaning up after the cow either. Sure, they liked to give tax breaks (there is some nice ice cream for you), but they did not really cut spending overall one little bit. They did cut spending on things THEY don’t like, but they also spent a crap load on things that THEY did like (like a money pit called Iraq). And now the Republicans want us to believe that they again are the party of “fiscal conservativism” and “fiscal responsibility”. Sorry, no sale here.

And as to notion of blame for the whole mess that Republicans warned Democrats...maybe that is true. But, then if they “knew” about the problems, then why did they not do something about it. The notion of blaming ANYONE side for this mess is just plain stupid. Just as it was stupid to blame all the bad stuff about Katrina on Bush. I dislike Bush...I REALLY dislike Bush...I think he was the worst President we have ever had. But, he was also a major league scap goat on Katrina. His administrations response was certainly MUCH less than stellar and Bush himself did a few REALLY stupid things from a perception point of view, but for me, there is LOTS of blame to go around and that includes the people of New Orleans. As engineers, we should all know that they were playing with fire by living in what essentially amounted to a bowl that was below sea level on a coast that could get hit by a hurricane. It was purely a matter of time before New Orleans got toasted by direct hit by a significant hurricane.

But, then everyone likes their ice cream and don’t think about the things needed to get the ice cream nor the potential consequences of eating the ice cream. We all like believe out ice cream never costs us anything, whether directly or indirectly.

And now I will return to shutting up about politics, eh, ice cream (not to mention it is making me hungry for some ice cream even though it is cold out and we just got some snow).

Regards,

Scott
Adrian, MI

On 2/21/09 12:15 PM, "ASLCSE@aol.com" <ASLCSE@aol.com> wrote:

In a message dated 2/21/2009 8:59:45 AM Pacific Standard Time, boyd@boydconsultinggroup.com writes:

How politicans get elected,

From a teacher in the Nashville area.

Who worries about "the cow" when it is all about the "Ice Cream?

The most eye-opening civics lesson I ever had was while teaching third grade this year.

The presidential election was heating up and some of the children showed an interest. I decided we would have an election for a class president. We would choose our nominees. They would make a campaign speech and the class would vote.

To simplify the process, candidates were nominated by other class members. We discussed what kinds of characteristics these students should have. We got many nominations and from those, Jamie and Olivia were picked to run for the top spot. The class had done a great job in their selections.

Both candidates were good kids. I thought Jamie might have an advantage because he got lots of parental support. I had never seen Olivia's mother.

The day arrived when they were to make their speeches Jamie went first. He had specific ideas about how to make our class a better place. He ended by promising to do his very best.

Everyone applauded. He sat down and Olivia came to the podium. Her speech was concise. She said, "If you will vote for me, I will give you ice cream." She sat down.

The class went wild. "Yes! Yes! We want ice cream." She surely could say more. She did not have to.

A discussion followed. How did she plan to pay for the ice cream? She wasn't sure.

Would her parents buy it or would the class pay for it? She didn't know.

The class really didn't care. All they were thinking about was ice cream.

Jamie was forgotten.

Olivia won by a landslide.

Every time Barack Obama opened his mouth he offered ice cream and fifty-two percent of the people reacted like nine year olds.

They want ice cream.

The other forty-eight percent of us know we're going to have to feed the cow and clean up the mess

Doug,
We do know that the "Republicans" warned the "Democrats" many times about the risky Subprime Loans. It started in the Clinton administration. If anyone want's to read the facts, let me know and I will send you a copy of the chronology.
Tony

A Good Credit Score is 700 or Above. See yours in just 2 easy steps! <http://pr.atwola.com/promoclk/100126575x1218822736x1201267884/aol?redir=http:%2F%2Fwww.freecreditreport.com%2Fpm%2Fdefault.aspx%3Fsc%3D668072%26hmpgID%3D62%26bcd%3DfebemailfooterNO62>

RE: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2

The R factor is intended to indicate the level of performance intended. If you drop the R value low enough, you are approaching an elastic response. As such, inelastic behavior as required by higher R factors, is not necessary. The inelastic behavior of concentric braced frames happens in the connections for systems such as the SCBF.

When we created the nonbuilding structures section in the mid 1990's, it was an effort to address issues such as these. There was an effort to eliminate OCBF's for buildings. We needed to retain them for nonbuilding structures such as large electric power plant boiler buildings. The SCBF's were not practical. And the decision to preclude them from building structures was not well grounded. We made a considered decision to allow OCBF in trade for lower R values which created higher demand. With the implied linear response, we were justified in deleting the ductility requirements as contained in the SCBF section.

The only reason that I brought up structures with no gussets was to exemplify that we do not necessarily need to develop ductility in the gussets. We still have the intended code structural performance with structures that do not meet the ductility requirements.

Regards, Harold Sprague

From: bill@polhemus.cc
To: seaint@seaint.org
Subject: Re: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2
Date: Sat, 21 Feb 2009 08:19:03 -0600

Thanks, Harold.

Problem: virtually all our connections involve gussets. What then?

William L. Polhemus, Jr. P.E.

Via iPhone 3G

On Feb 21, 2009, at 1:25 AM, Harold Sprague <spraguehope@hotmail.com> wrote:

Bill,
Your colleague is correct. ICC has a presence in the development of ASCE 7 and the intent is for the ASCE 7 to be applicable as invoked by the IBC. The nonbuilding structures section was specifically developed in order to address the specific needs of nonbuilding (industrial structures).

There are many industrial structures that require bracing to elements with no gusset plates at all thus the special detailing requirements are not possible. The use of these structures could not be precluded just because they were in a region of high seismic demand. The concept of dropping the R value to a point approximating an elastic response was specifically developed to avoid seismic detailing where seismic detailing was not feasible.

You owe your colleague and me a beer.

Regards, Harold Sprague

> Date: Fri, 20 Feb 2009 21:14:40 -0600
> From: bill@polhemus.cc
> To: seaint@seaint.org
> Subject: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2
>
> I'm having a disagreement with a colleague regarding what I perceive to
> be a conflict between IBC 2006 Section 2205.2.2, which states that
> seismic detailing of structural steel is required in SDC D, E and F, and
> ASCE 7-05.
>
> Since we're doing mostly industrial, petrochemical and refinery work, we
> frequently make reference to Chapter 15 of ASCE 7. In Table 15.4-1 of
> ASCE 7, it allows the use of R = 1.5 for ordinary concentrically-braced
> steel frames in SDC "D" when you don't want to use the Seismic
> Provisions of AISC 341-05. This fellow has taken to doing this in all
> cases so that they don't have to worry about all the detailing
> provisions - in essence, they can just do a "normal" frame for
> equipments supports, platforms, etc. You end up with potentially heavier
> foundations - eh, it's just concrete - and maybe a bit more steel, but
> you don't have to worry about all the detailing for ductile behavior,
> goes that theory.
>
> I, however, believe that Section 2205.2.2 of IBC 2006 takes precedence,
> and overrules ASCE 7 on this score. Of course, you can still use R = 1.5
> if you want to, but you're still going to have to do the detailing.
>
> My friend claims I'm "reading it wrong," and seems to feel that the IBC
> 2006 applies ONLY to Chapter 12, and that Chapter 15 is another kettle
> of fish, so to speak. I respond that Chapter 15 specifically says that
> it's provisions are to be used IN ADDITION to those of Chapter 12, to
> handle non-building structures.
>
> And so back and forth it goes, with no resolution in sight. I think this
> guy is very "ASCE 7" oriented, whereas I'm more inclined to look at the
> hierarchy of the documents - IBC 2006 incorporates ASCE 7-05, not the
> other way around.
>
> Comments?
>
> ******* ****** ******* ******** ******* ******* ******* ***
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Re: Remove from list

In a message dated 2/21/2009 8:59:45 AM Pacific Standard Time, boyd@boydconsultinggroup.com writes:

How politicans get elected,

From a teacher in the Nashville area.

Who worries about "the cow" when it is all about the "Ice Cream?

The most eye-opening civics lesson I ever had was while teaching third grade this year.

The presidential election was heating up and some of the children showed an interest. I decided we would have an election for a class president. We would choose our nominees. They would make a campaign speech and the class would vote.

To simplify the process, candidates were nominated by other class members.  We discussed what kinds of characteristics these students should have.  We got many nominations and from those, Jamie and Olivia were picked to run for the top spot. The class had done a great job in their selections.

Both candidates were good kids. I thought Jamie might have an advantage because he got lots of parental support. I had never seen Olivia's mother.

The day arrived when they were to make their speeches Jamie went first. He had specific ideas about how to make our class a better place. He ended by promising to do his very best.

Everyone applauded. He sat down and Olivia came to the podium. Her speech was concise. She said, "If you will vote for me, I will give you ice cream." She sat down.

The class went wild. "Yes! Yes! We want ice cream." She surely could say more. She did not have to.

A discussion followed. How did she plan to pay for the ice cream? She wasn't sure.

Would her parents buy it or would the class pay for it?  She didn't know.

The class really didn't care. All they were thinking about was ice cream.

Jamie was forgotten.

Olivia won by a landslide.

Every time Barack Obama opened his mouth he offered ice cream and fifty-two percent of the people reacted like nine year olds.

They want ice cream.

The other forty-eight percent of us know we're going to have to feed the cow and clean up the mess

Doug,

We do know that the "Republicans" warned the "Democrats" many times about the risky Subprime Loans. It started in the Clinton administration. If anyone want's to read the facts, let me know and I will send you a copy of the chronology.

Tony

A Good Credit Score is 700 or Above. See yours in just 2 easy steps!

RE: Remove from list

Bill:

You should listen to this ice cream eating idiot! He’s well informed! It’s amazing that someone so eloquent would so completely understand that it is people from Texas that are responsible for the end of Democracy. I received an amusing email that sums it up nicely!

Doug

How politicans get elected,

From a teacher in the Nashville area.

Who worries about "the cow" when it is all about the "Ice Cream?

The most eye-opening civics lesson I ever had was while teaching third grade this year.

The presidential election was heating up and some of the children showed an interest. I decided we would have an election for a class president. We would choose our nominees. They would make a campaign speech and the class would vote.

To simplify the process, candidates were nominated by other class members. We discussed what kinds of characteristics these students should have. We got many nominations and from those, Jamie and Olivia were picked to run for the top spot. The class had done a great job in their selections.

Both candidates were good kids. I thought Jamie might have an advantage because he got lots of parental support. I had never seen Olivia's mother.

The day arrived when they were to make their speeches Jamie went first. He had specific ideas about how to make our class a better place. He ended by promising to do his very best.

Everyone applauded. He sat down and Olivia came to the podium. Her speech was concise. She said, "If you will vote for me, I will give you ice cream." She sat down.

The class went wild. "Yes! Yes! We want ice cream." She surely could say more. She did not have to.

A discussion followed. How did she plan to pay for the ice cream? She wasn't sure.

Would her parents buy it or would the class pay for it? She didn't know.

The class really didn't care. All they were thinking about was ice cream.

Jamie was forgotten.

Olivia won by a landslide.

Every time Barack Obama opened his mouth he offered ice cream and fifty-two percent of the people reacted like nine year olds.

They want ice cream.

The other forty-eight percent of us know we're going to have to feed the cow and clean up the mess

From: erik_g@cox.net [mailto:erik_g@cox.net]
Sent: Friday, February 20, 2009 11:12 PM
To: seaint@seaint.org
Subject: RE: Remove from list

Bill, shut your face. It is scum bag Big Texan loud mouthed people like yourself that have ran our economy into the ground. Now go stuff your fat face with a few big macs, "Freedom fries" and a few diet Coke's.

-----Original Message-----
From: Bill Polhemus [mailto:bill@polhemus.cc]
Sent: Friday, February 20, 2009 6:18 PM
To: <seaint@seaint.org>
Subject: Re: Remove from list

I just wanted you to know, I was so impressed with your message that I printed 96 copies to hand out to all the folks in our office.

Thanks. I feel like I just gave Mother Gaea a B-I-G hug!

William L. Polhemus, Jr. P.E.

Via iPhone 3G

On Feb 20, 2009, at 6:14 PM, "Souther, Joseph" <SoutherJT@cdm.com> wrote:

P Please consider the environment before printing this email.

Re: Wind loads: ASD or Strength?

>>> Now, the issue of C&C vs MWFRS pressures is a wee bit more messy and
>>> is not suprising that many get confused...
>>But it's not "confusing" for the same reason. It's a completely
>>different concept than "service vs. strength." It has to do with
>>statistical probabilities that a small area is equally likely to see a
>>higher pressure as an entire MWFRS is to see an "average" pressure.
>>The Commentary is your friend.
>
> I agree with Scott on this one. CC isn't nearly as simple as you've
> stated – if it were, why wouldn't we just use the large trib area
> loading based on CC for the Main wind systems?

Please note I didn't say "simple." I agree, it's confusing. It's just that it's "confusing" for a different reason than the explanation of why seismic loads are "strength level" while wind loads are "service level."

I guess I was trying to be clever. I should NEVER try to be clever.

> I've heard an entirely different opinion of what CC means from nearly
> every engineer I've asked. I've even witnessed several engineers
> debating this "line" for hours only to never completely agree...

I had it explained to me by Kishor Mehta and the late Dale Perry. Their explanation was not hard to follow (with pictures), and I came away believing I understood it.

Yea, me.

******* ****** ******* ******** ******* ******* ******* ***
* Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
* This email was sent to you via Structural Engineers
* Association of Southern California (SEAOSC) server. To
* subscribe (no fee) or UnSubscribe, please go to:
*
* http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad@seaint.org. Remember, any email you
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* site at: http://www.seaint.org
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Re: Wind loads: ASD or Strength?

>From: Bill Polhemus <bill@polhemus.cc>

>To: seaint@seaint.org

>Subject: Re: Wind loads: ASD or Strength?

>Scott Maxwell wrote:

>> Now, the issue of C&C vs MWFRS pressures is a wee bit more messy and

>> is not suprising that many get confused...

>But it's not "confusing" for the same reason. It's a completely

>different concept than "service vs. strength." It has to do with

>statistical probabilities that a small area is equally likely to see a

>higher pressure as an entire MWFRS is to see an "average" pressure.

>The Commentary is your friend.

I agree with Scott on this one. CC isn’t nearly as simple as you’ve stated – if it were, why wouldn’t we just use the large trib area loading based on CC for the Main wind systems?

I’ve heard an entirely different opinion of what CC means from nearly every engineer I’ve asked. I’ve even witnessed several engineers debating this “line” for hours only to never completely agree...

However, the opinion that I’ve come across the most, and come to believe to be the most correct myself, is that CC loads are bloated loads, based on (as you said) peak loads over a smaller area – much like a wave crest can be substantially higher than mean sea level - purposed for protecting the integrity of the building envelope. i.e. anything that would change the system from, say, enclosed to partially enclosed given its individual failure - keyword here being individual. Take residential roof trusses for example - If only truss connection fails, the envelope will not likely be compromised, thus the use of MWFRS loads is acceptable. But if say the truss plates fail, the truss may come through the ceiling pulling the sheathing in with it – thus they are CC. But what about wall studs? The truss itself? This is where professional opinion and local precedence starts taking over and the debates begin. Some engineers don’t even agree that the truss clip should be MWFRS...

Richard Calvert

Re: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2

Thanks, Harold.

Problem: virtually all our connections involve gussets. What then?

William L. Polhemus, Jr. P.E.

Via iPhone 3G

On Feb 21, 2009, at 1:25 AM, Harold Sprague <spraguehope@hotmail.com> wrote:

Bill,
Your colleague is correct. ICC has a presence in the development of ASCE 7 and the intent is for the ASCE 7 to be applicable as invoked by the IBC. The nonbuilding structures section was specifically developed in order to address the specific needs of nonbuilding (industrial structures).

There are many industrial structures that require bracing to elements with no gusset plates at all thus the special detailing requirements are not possible. The use of these structures could not be precluded just because they were in a region of high seismic demand. The concept of dropping the R value to a point approximating an elastic response was specifically developed to avoid seismic detailing where seismic detailing was not feasible.

You owe your colleague and me a beer.

Regards, Harold Sprague

> Date: Fri, 20 Feb 2009 21:14:40 -0600
> From: bill@polhemus.cc
> To: seaint@seaint.org
> Subject: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2
>
> I'm having a disagreement with a colleague regarding what I perceive to
> be a conflict between IBC 2006 Section 2205.2.2, which states that
> seismic detailing of structural steel is required in SDC D, E and F, and
> ASCE 7-05.
>
> Since we're doing mostly industrial, petrochemical and refinery work, we
> frequently make reference to Chapter 15 of ASCE 7. In Table 15.4-1 of
> ASCE 7, it allows the use of R = 1.5 for ordinary concentrically-braced
> steel frames in SDC "D" when you don't want to use the Seismic
> Provisions of AISC 341-05. This fellow has taken to doing this in all
> cases so that they don't have to worry about all the detailing
> provisions - in essence, they can just do a "normal" frame for
> equipments supports, platforms, etc. You end up with potentially heavier
> foundations - eh, it's just concrete - and maybe a bit more steel, but
> you don't have to worry about all the detailing for ductile behavior,
> goes that theory.
>
> I, however, believe that Section 2205.2.2 of IBC 2006 takes precedence,
> and overrules ASCE 7 on this score. Of course, you can still use R = 1.5
> if you want to, but you're still going to have to do the detailing.
>
> My friend claims I'm "reading it wrong," and seems to feel that the IBC
> 2006 applies ONLY to Chapter 12, and that Chapter 15 is another kettle
> of fish, so to speak. I respond that Chapter 15 specifically says that
> it's provisions are to be used IN ADDITION to those of Chapter 12, to
> handle non-building structures.
>
> And so back and forth it goes, with no resolution in sight. I think this
> guy is very "ASCE 7" oriented, whereas I'm more inclined to look at the
> hierarchy of the documents - IBC 2006 incorporates ASCE 7-05, not the
> other way around.
>
> Comments?
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * Read list FAQ at: http://www.seaint.org/list_FAQ.asp
> *
> * This email was sent to you via Structural Engineers
> * Association of Southern California (SEAOSC) server. To
> * subscribe (no fee) or UnSubscribe, please go to:
> *
> * http://www.seaint.org/sealist1.asp
> *
> * Questions to seaint-ad@seaint.org. Remember, any email you
> * send to the list is public domain and may be re-posted
> * without your permission. Make sure you visit our web
> * site at: http://www.seaint.org
> ******* ****** ****** ****** ******* ****** ****** ********

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Re: Remove from list

I missed this place!

William L. Polhemus, Jr. P.E.

Via iPhone 3G

On Feb 20, 2009, at 10:12 PM, <erik_g@cox.net> wrote:

Bill, shut your face. It is scum bag Big Texan loud mouthed people like yourself that have ran our economy into the ground. Now go stuff your fat face with a few big macs, "Freedom fries" and a few diet Coke's.

-----Original Message-----
From: Bill Polhemus [mailto:bill@polhemus.cc]
Sent: Friday, February 20, 2009 6:18 PM
To: <seaint@seaint.org>
Subject: Re: Remove from list

I just wanted you to know, I was so impressed with your message that I printed 96 copies to hand out to all the folks in our office.

Thanks. I feel like I just gave Mother Gaea a B-I-G hug!

William L. Polhemus, Jr. P.E.
Via iPhone 3G

On Feb 20, 2009, at 6:14 PM, "Souther, Joseph" <SoutherJT@cdm.com> wrote:

P Please consider the environment before printing this email.

Friday, February 20, 2009

RE: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2

Bill,
Your colleague is correct. ICC has a presence in the development of ASCE 7 and the intent is for the ASCE 7 to be applicable as invoked by the IBC. The nonbuilding structures section was specifically developed in order to address the specific needs of nonbuilding (industrial structures).

There are many industrial structures that require bracing to elements with no gusset plates at all thus the special detailing requirements are not possible. The use of these structures could not be precluded just because they were in a region of high seismic demand. The concept of dropping the R value to a point approximating an elastic response was specifically developed to avoid seismic detailing where seismic detailing was not feasible.

You owe your colleague and me a beer.

Regards, Harold Sprague

> Date: Fri, 20 Feb 2009 21:14:40 -0600
> From: bill@polhemus.cc
> To: seaint@seaint.org
> Subject: IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2
>
> I'm having a disagreement with a colleague regarding what I perceive to
> be a conflict between IBC 2006 Section 2205.2.2, which states that
> seismic detailing of structural steel is required in SDC D, E and F, and
> ASCE 7-05.
>
> Since we're doing mostly industrial, petrochemical and refinery work, we
> frequently make reference to Chapter 15 of ASCE 7. In Table 15.4-1 of
> ASCE 7, it allows the use of R = 1.5 for ordinary concentrically-braced
> steel frames in SDC "D" when you don't want to use the Seismic
> Provisions of AISC 341-05. This fellow has taken to doing this in all
> cases so that they don't have to worry about all the detailing
> provisions - in essence, they can just do a "normal" frame for
> equipments supports, platforms, etc. You end up with potentially heavier
> foundations - eh, it's just concrete - and maybe a bit more steel, but
> you don't have to worry about all the detailing for ductile behavior,
> goes that theory.
>
> I, however, believe that Section 2205.2.2 of IBC 2006 takes precedence,
> and overrules ASCE 7 on this score. Of course, you can still use R = 1.5
> if you want to, but you're still going to have to do the detailing.
>
> My friend claims I'm "reading it wrong," and seems to feel that the IBC
> 2006 applies ONLY to Chapter 12, and that Chapter 15 is another kettle
> of fish, so to speak. I respond that Chapter 15 specifically says that
> it's provisions are to be used IN ADDITION to those of Chapter 12, to
> handle non-building structures.
>
> And so back and forth it goes, with no resolution in sight. I think this
> guy is very "ASCE 7" oriented, whereas I'm more inclined to look at the
> hierarchy of the documents - IBC 2006 incorporates ASCE 7-05, not the
> other way around.
>
> Comments?
>
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Windows Live™: Discover 10 secrets about the new Windows Live. View post.

RE: Remove from list

-----Original Message-----
From: Bill Polhemus [mailto:bill@polhemus.cc]
Sent: Friday, February 20, 2009 6:18 PM
To: <seaint@seaint.org>
Subject: Re: Remove from list

I just wanted you to know, I was so impressed with your message that I printed 96 copies to hand out to all the folks in our office.

Thanks. I feel like I just gave Mother Gaea a B-I-G hug!

William L. Polhemus, Jr. P.E.
Via iPhone 3G

On Feb 20, 2009, at 6:14 PM, "Souther, Joseph" <SoutherJT@cdm.com> wrote:

P Please consider the environment before printing this email.

Re: Wind forces

Tarek Mokhtar wrote:

Re: Wind forces
Hugh,

I believe this design wind pressure stayed until and including the 1982 UBC, and all these buildings

designed under these codes were destroyed >:-o

Actually, there were QUITE A FEW of them in Florida that were destroyed in H. Andrew. That's the reason Florida finally got on the stick and finally enacted a statewide building code.

http://www.allbusiness.com/fabricated-metal-product-manufacturing/architectural/706113-1.html

Re: Wind loads: ASD or Strength?

Jordan Truesdell, PE wrote:

The code gives you no option for taking a more conservative route.

That's because competition leads to economy. Thank Obama for steel studs. (Not meaning to blaspheme, of course).

Re: Wind loads: ASD or Strength?

Scott Maxwell wrote:
> Now, the issue of C&C vs MWFRS pressures is a wee bit more messy and
> is not suprising that many get confused...
But it's not "confusing" for the same reason. It's a completely
different concept than "service vs. strength." It has to do with
statistical probabilities that a small area is equally likely to see a
higher pressure as an entire MWFRS is to see an "average" pressure.

The Commentary is your friend.

Re: FW: Wind loads: ASD or Strength?

Andy Heigley wrote:

Jason:

I don't know where he's finding the wind pressure to be a strength level load, especially if you are using the Allowable Load Combinations of the building code... I would tell him that he's not following the Allowable Load combinations of the Building Code, and what he's using is not listed as an alternative load combination either...

It is astonishing to me how complicated people can make such a simple concept.

Everything is "service level" except for earthquake. That's pretty much it.

IBC 2006 - SEISMIC DESIGN OF STEEL - 2205.2.2

I'm having a disagreement with a colleague regarding what I perceive to
be a conflict between IBC 2006 Section 2205.2.2, which states that
seismic detailing of structural steel is required in SDC D, E and F, and
ASCE 7-05.

Since we're doing mostly industrial, petrochemical and refinery work, we
frequently make reference to Chapter 15 of ASCE 7. In Table 15.4-1 of
ASCE 7, it allows the use of R = 1.5 for ordinary concentrically-braced
steel frames in SDC "D" when you don't want to use the Seismic
Provisions of AISC 341-05. This fellow has taken to doing this in all
cases so that they don't have to worry about all the detailing
provisions - in essence, they can just do a "normal" frame for
equipments supports, platforms, etc. You end up with potentially heavier
foundations - eh, it's just concrete - and maybe a bit more steel, but
you don't have to worry about all the detailing for ductile behavior,
goes that theory.

I, however, believe that Section 2205.2.2 of IBC 2006 takes precedence,
and overrules ASCE 7 on this score. Of course, you can still use R = 1.5
if you want to, but you're still going to have to do the detailing.

My friend claims I'm "reading it wrong," and seems to feel that the IBC
2006 applies ONLY to Chapter 12, and that Chapter 15 is another kettle
of fish, so to speak. I respond that Chapter 15 specifically says that
it's provisions are to be used IN ADDITION to those of Chapter 12, to
handle non-building structures.

And so back and forth it goes, with no resolution in sight. I think this
guy is very "ASCE 7" oriented, whereas I'm more inclined to look at the
hierarchy of the documents - IBC 2006 incorporates ASCE 7-05, not the
other way around.

Comments?

Design of Double Angle Shear Connection for Extreme Ductility

Dear Mr. Felker:

I suggest the following references for information on ductility of
bolted double angles subjected to rotation and rotation combined with
tension pull out.

1.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib1>
A. Astaneh, M. Nader and L. Malik, Cyclic behavior of double angle
connections. /J. Struct. Engng/ *115* 5 (1989), pp. 1101–1118.

2.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib2>
M. De Stefano, A. de Luca and A. Astaneh, Modeling of cyclic
moment–rotation response of double-angle connections. /J. Struct. Engng/
*120* 1 (1994), pp. 212–229. **
<http://www.sciencedirect.com/science?_ob=RedirectURL&_method=outwardLink&_partnerName=3&_targetURL=http%3A%2F%2Fdx.doi.org%2F10.1061%2F%28ASCE%290733-9445%281994%29120%3A1%28212%29&_acct=C000059607&_version=1&_userid=4420&md5=d7a8879d3515a56a3ef15bcd278cabbf>
3.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib3>
A. Astaneh and I. Ho, Behavior and design of angle connections subjected
to cyclic axial force and shear. In: A.H-S. Ang and R. Villaverde,
Editors, /Structural engineering in natural hazards mitigation, vol. 2/,
ASCE, New York (1993), pp. 1232–1237.

4.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib4>
Azizinamini A, Bradburn JH, Radziminski JB. Initial stiffness of
semi-ridig steel beam-to-column connections. J Construct Steel Res
1987;71–90.

5.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib5>
S. Guravich and J.L. Dawe, Bolted double angle connections in combined
shear and tension. In: /Proceedings of the AISC National Steel
Construction Congress/, American Institute of Steel Construction,
Chicago (1998) [8/1-8/15].

6.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib6>
S. Guravich and J.L. Dawe, Simple beam connections in combined shear and
tension. /J. Construct. Steel Res./ *46* (1998), pp. 241–242.

7.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib7>
C.W. Lewitt, E. Chesson, Jr. and W.H. Munse. /Restraint characteristics
of flexible and bolted beam-to-column connections. Bulletin Number 500/,
Engineering Experiment Station, University of Illinois (1969).

8.
<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2Y-44B22K9-G&_user=4420&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059607&_version=1&_urlVersion=0&_userid=4420&md5=b5184e643b1f484cb7a039adf6635acb#bbib7>
K. Hong, J.G. Yang and S.K. Lee. /Moment-rotation behavior of double
angle connections subjected to shear load. /J. Engineering Structures,
Elsevier Science Ltd., (2002).

9. J. Shen, and A. Astaneh-Asl, A. / "Hysteresis Model of Bolted Angle
Connections"/, J. of Steel Constructional Research, 54, (1999), pp.
317-343.

In number 1-3 and 9 we have reported on test results of double angles
subjected to cyclic rotation as well as rotation plus axial push pull.

Based on what we know of the behavior, the bolted/bolted double angles
where the angles are bolted to the beam as well as to the column (or
girders) have quite large ductility , in the order of 0.10-0.15 radians
rotation , provided that failure mode of the bolts in tension or shear
do not govern. Also net section failure of the angle should not be
governing failure mode. The governing failure mode has to be the angle
leg yielding followed by bearing failure of bolts in sher. The edge
distance of bolts on the back to back legs also needs to be greater than
what is in the AISC spec ( about 1.5x dia) . We have suggested edge
distance for these cases of catenary force applications be at least 2 x
dia of bolt. If the angles are welded to the column, the ductility would
be much less than bolted/bolted ones and not as reliable either.

Other sources that might be of some help (I hope, since they are my own
Steel TIPS reports ) are:

1. Progressive Collapse Prevention of Steel Frames with Shear
Connections <http://www.steeltips.org/steeltips/tip_details.php?id=97>
2. Notes on Design of Double-Angle and Tee Shear Connections for Gravity
and Seismic Loads <http://www.steeltips.org/steeltips/tip_details.php?id=91>

These two reports have information on behavior and design of shear
connections including double angles subjected to bending and axial tension.

If you have a specific concern or question, specially on our own work,
please send me an e-mail off the list and I will be happy to help.

Best wishes
A. Astaneh-Asl, Ph.D., P.E.
Professor and Consultant on structural and Earthquake Engineering and
Protection of Structures against Blast and Impact
(www.ce.berkeley.edu/~astaneh), (www.astaneh.net)

---------------
Subject: Design of Double Angle Shear Connection for Extreme Ductility
Date: Thu=2C 19 Feb 2009 21:10:43 -0500
From: bfelker@mmmdesigngroup.com
To: seaint@seaint.org

I am currently trying to design a double angle connection for ductile response
to catenary loads induced by support removal. This is for a progressive
collapse avoidance design. In order to achieve the assumed catenary structural
response assumed in the tie forces design method=2C the beam end connections
for structural steel members utilized as ties must be designed to
undergo 0.20-radians of rotation=2C and still maintain the required capacity.
I think I have figured out a way to do this=2C but would like to see if
any research has been done on this type of behavior=2C and/or if a text has
been written which addresses this issue. Any direction would be much appreciated
as I'm not sure where to start looking. Thanks.

Brian P. Felker, PE
Building Section Manager
Structural Department
MMM DESIGN GROUP
bfelker@mmmdesigngroup.com
757.623.1641

_________________________________________________________________
Windows Live=99: Keep your life in sync.=20
http://windowslive.com/howitworks?ocid=3DTXT_TAGLM_WL_t1_allup_howitworks_0=
22009=

Re: Remove from list

I just wanted you to know, I was so impressed with your message that I printed 96 copies to hand out to all the folks in our office.

Thanks. I feel like I just gave Mother Gaea a B-I-G hug!

William L. Polhemus, Jr. P.E.

Via iPhone 3G

On Feb 20, 2009, at 6:14 PM, "Souther, Joseph" <SoutherJT@cdm.com> wrote:

P Please consider the environment before printing this email.

Re: Tilt Up Building Seismic force Resisting System

It may be a special concrete shear wall...

What are your site parameters dictating? have you calc'd SS, S1, Sds, Sd1? Occupancy?

On Fri, Feb 20, 2009 at 4:08 PM, Doug Mayer <doug.mayer@taylorteter.com> wrote:

From what I understand, it would typically be an intermediate precast shear wall (B-9).

Doug Mayer, SE

From: xmy987@gmail.com [mailto:xmy987@gmail.com]
Sent: Friday, February 20, 2009 3:53 PM
To: seaint@seaint.org
Subject: Tilt Up Building Seismic force Resisting System

Does someone know which item from ASCE7-05 Table 12.2-1 would apply to a concrete tilt up building?

Thanks

Bill

--
David Topete, SE

RE: Tilt Up Building Seismic force Resisting System

From what I understand, it would typically be an intermediate precast shear wall (B-9).

Doug Mayer, SE

From: xmy987@gmail.com [mailto:xmy987@gmail.com]
Sent: Friday, February 20, 2009 3:53 PM
To: seaint@seaint.org
Subject: Tilt Up Building Seismic force Resisting System

Does someone know which item from ASCE7-05 Table 12.2-1 would apply to a concrete tilt up building?

Thanks

Bill

RE: Tilt Up Building Seismic force Resisting System

But there are special, ordinary, precast, etc.., which one?

Thanks

From: David Topete [mailto:d.topete73@gmail.com]
Sent: Friday, February 20, 2009 3:59 PM
To: seaint@seaint.org
Subject: Re: Tilt Up Building Seismic force Resisting System

Concrete shear wall/bearing wall

On Fri, Feb 20, 2009 at 3:52 PM, <xmy987@gmail.com> wrote:

Does someone know which item from ASCE7-05 Table 12.2-1 would apply to a concrete tilt up building?

Thanks

Bill

--
David Topete, SE

Re: Tilt Up Building Seismic force Resisting System

Concrete shear wall/bearing wall

On Fri, Feb 20, 2009 at 3:52 PM, <xmy987@gmail.com> wrote:

Does someone know which item from ASCE7-05 Table 12.2-1 would apply to a concrete tilt up building?

Thanks

Bill

--
David Topete, SE

Tilt Up Building Seismic force Resisting System

Does someone know which item from ASCE7-05 Table 12.2-1 would apply to a concrete tilt up building?

Thanks

Bill

Re: Steel connection design

Dear Mr. Cabalero:
I would also add the following publications which have design oriented information on connections:

1. Handbook of Structural Steel Connection Design and Details, by Akbar R. Tamboli, published by McGraw Hill. This is a more recent book relative to Omer Blodgett's and the AISC books recommended in other responses, which by the way I second their recommendations.

2. Guide to Design Criteria for Bolted and Riveted Joints, Second Edition, by G.L. Kulak, J.W. Fisher and J.H.A. Struik, published by the AISC and freely available for download at: http://www.boltcouncil.org/files/2ndEditionGuide.pdf. This is a must-have for anyone who does bolt or rivet design or evaluation.

As for strength of the splice (in steel and composite structures) and what it should be, it depends on the type of structure and the loads the splice has to resist. Traditionally, in buildings, and even in current practice, splices that carry only gravity load are designed to resist the applied design forces and not for the capacity of the spliced members. For loads that involve wind, the situation is not very clear to me. In most cases i have seen for cases that involve combined wind and gravity , the designers still use the applied forces established by the analysis to design splices. In some important cases, the splices for wind+ gravity cases are designed for the capacity of the members connected as well. We have to remember that this decision is left to discretion of the structural engineer.
For cases involving seismic, again depending of the type of the structural system and level of ductility demand one can decide to design the splices for either applied design forces or for the capacity of the members. If If ductility demand is high , say the R-factor (Response Modification Factor) is higher than 3.0, then it might be prudent to design splices for the capacity of the members. certainly if the lateral force resisting system is "special" such as Special Moment Resisting Frame or Special Concentrically Braced Frame, then the splices of the lateral force resisting system system should be designed for to develop capacity of the members spliced. Even the splices of collectors and primary gravity load carrying members such as columns, in my opinion , should be designed for capacity of the members since the actual seismic forces developed in the entire structure will be different than the simplistic Static Equivalent forces we use in force-based design.

In bridges, the situation is different and is more stringent than buildings. Until 1940's AASHTO specifications required that the splices be designed to develop member capacities ( allowable strength of splice be greater than the allowable strength of the members). Since then the requirement has been watered down and the current AASHTO Specifications (2007) requires that splices be designed to the larger of 75% of the capacity or (Capacity+applied forces)/2 . These requirements are regardless of the nature of applied loads.

If I had a choice , I would design all splices that are on the non-redundant load path to develop capacity of the members since in these cases, the failure of a splice and lack of a parallel redundant load path can result in partial or full progressive collapse. That catastrophe of course would be a very high price to pay for not using couple of hundreds or even couple of thousands of extra bolts in the structure that may not cost more than a 0.1% of the total cost!

I am more of a follower of the late John Alexander Low Waddell(1854-1938) , one the greatest bridge engineers and structural engineers of all times who in his famous "Des Pontibus" book in 1898 has said: "The strength of a structure is measured by the strength of its weakest part". I don't want to make the splices to be the weakest part of my structure and determine the strength of the entire structure. Do you?

Hope this is of some help.

A. Astaneh-Asl, Ph.D., P.E.
Professor and Consultant on structural and Earthquake
Engineering and Protection of Structures against Blast and Impact
(www.ce.berkeley.edu/~astaneh), (www.astaneh.net)
=====================================

Dear List

Please advise me with a good reference material discussing steel
connection design or related to steel connection design(i.e. code, books,
pdf, sites or lectures).

Furthermore, on splice connection design, what do thing is the best design
approach(force based design method or member capacity based design
method). Using member capacity design, it may require huge number of bolts
and a thicker plates especially if the member that is spliced is a huge
size wide flange member. Please advise which is the correct approach.

Thank you in advance.

Regards,

David Francis C. Caballero
Structural Engineer
License No. 0103970
Professional Regulation Commission
Manila, Philippines
email: engrfrancis05@yahoo.com
CP#: +63917-981-8588

RE: ASCE 7-05: RSA Procedure per 12.9

-----Original Message-----
From: bill@polhemus.cc [mailto:bill@polhemus.cc]
Sent: Friday, February 20, 2009 11:05 AM
To: seaint@seaint.org
Subject: Re: ASCE 7-05: RSA Procedure per 12.9

>> ...The result should be
>> compared to the equivalent lateral force base shear and only
increased
>> if it is below 85% of that value -- you cannot scale it down.

That is correct. Thanks.

> More later, I'm sure. Hope this is helpful to others listening in.

Thanks again.