Structural Engineering: 2007-06-10

Saturday, June 16, 2007

Re: ASCE 7-05 Errors

Time for everyone to wake up.

The 2% error rate does not seem that high, but what was missed in that analysis, is that if just one formula is completely off, your entire design can be 100% off. That is what you have to keep in mind.

What one has to consider is that this is a legal document. When we as engineers follow this 'technical publication', we become 'legally' responsible for mistakes that are out of our control. Now can someone tell me for sure that all the errors have been picked up? Will a new errata be published 3 months from now, 2 months after I completed a new project? Am I safe in basing my calculations on a publication that is so full of error?

Keep in mind that the same problems were encountered with the '97 UBC and the 3 volumes of the Seismic manuals, and it took a couple of years to iron thing out. That's why there is no excuse for the sloppy proofing this time around!

There has to be more proof reading, and if more time is needed, than so be it. Where is the rush? Are buildings collapsing all around us? Or is this a money making venture?

More mistakes will be made by practicing engineers by this constant code changes, than if the existing code is just left in place for a while longer.

I don't want to get personal with anyone, I just have to vent.

Andrew Vidikan, PE

-----Original Message-----
From: Larry Hauer
To: seaint@seaint.org
Sent: Thu, 7 Jun 2007 2:33 pm
Subject: RE: ASCE 7-05 Errors

Yes, no set of construction documents is 100% error free and no technical publication is 100% error free, but 24 pages of errata sounds excessive. Most constr. docs errors are typos inwhich we can interpret the meaning, (ie. "wood beam" spelled "wood bem." But a mistake in a formula in a technical publication can have disasterous results, (i.e. a "greater than" sign reversed to "less than"). From the postings, it sounds like ASCE dropped the ball at our expense.

Larry Hauer S.E.

>From: "Mark E. Deardorff" <mdeardorff@burkett-wong.com>
>Reply-To: <seaint@seaint.org>
>To: <seaint@seaint.org>
>Subject: RE: ASCE 7-05 Errors
>Date: Thu, 7 Jun 2007 13:27:12 -0700
>
>Not as bad as AISC's goof on the Seismic Design Manual. It was too >extensive
>to treat with errata.
>
>Mark E. Deardorff, S.E.
>Structural Engineer
> <http://www.burkett-wong.com/> Burkett & Wong Engineers
>3434 4th Ave
>San Diego, CA 92103
>P 619.299.5550
>F 619.299.9934
>mdeardorff@burkett-wong.com
>
>
>
> _____
>
>From: Garner, Robert [mailto:rgarner@moffattnichol.com]
>Sent: Wednesday, June 06, 2007 2:15 PM
>To: seaint@seaint.org
>Subject: ASCE 7-05 Errors
>
>
>
>Just a tip that the latest errata for ASCE 7-05 is available from
>SEInstitute.org All twenty four pages! In addition, S.K. Ghosh >published
>some ASCE 7 Seismic Provisions Errata in the April issue of Structural
>Engineer. I don't know if Ghosh's errata was picked up by SEInstitute or
>not.
>
>
>
>These errata are so extensive that I think you can ignore buying ASCE 7-05
>and just download the errata for free.
>
>
>
>I think I'm just going to go ahead and do really sloppy engineering on my
>next project - I can always issue errata, right?
>
>
>
>Bob Garner, S.E.
>
>
>
>R. Garner
>
>Moffatt & Nichol
>
>Tel.: (619) 220-6050
>
>Fax.: (619) 220-6055
>
>e-mail: rgarner@moffattnichol.com
>
>
>
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RE: Can an engineer practice with a felony conviction in California?

Dennis,

Doing a quick search of the BORPELS website, the query returned this entry. http://www.dca.ca.gov/pels/e_plppe.pdf Go to page 20 of the doc, and the answer on the following page indicates a felony is grounds for disciplinary action. What that is, I guess, remains specific to the situation. Good luck.

David A. Topete, SE

From: Dennis Wish [mailto:dennis.wish@verizon.net]
Sent: Saturday, June 16, 2007 3:33 PM
To: seaint@seaint.org
Subject: Can an engineer practice with a felony conviction in California?

Will an employee of a municipality who is a licensed PE and who has just recently been convicted of a felony be allowed to practice? The engineer I am referring to is employed by a municipality outside my area, but this engineer has an open complaint with BORPELS for nearly five years. He was recently convicted of a felony and was an employee in one of the county offices outside our area. He was convicted of taking bribes to accelerate the plan review for pool permits in his county and he pleaded guilty. I notices from the article I read that he was tried by the felony division of the county and has been given 300 hours of community service, a stiff fine and he can not hold public office or work for any municipality in the state.

Will BORPELS pick upon on this automatically, or is he still allowed to practice since he was not found incompetent, only ethically and morally untrustworthy? I have a compliant filed for another engineer with BORPELS and I believe the complaint I filed nearly five years ago that has not been acted upon yet due to loss of financial support from the state has delayed all complaints. However, this is the engineer who is wet stamping the drawings of the non-engineer who is representing himself as a Structural Consultant and is not licensed. It occurred to me after putting two and two together following a comment I heard a local contractor tell this engineer during a seminar I attended over a year ago that the non-engineer may have been given a second stamp and allowed by the engineer who was convicted to seal drawings. The non-engineer has the education and work experience to take the exams but is older and has not applied to take the exams as he worked for a company that did not require him to be licensed. Once he was laid off, he found the need but not the time or the desire and proceeded to set up his company under his own name but using one engineer for a number of years to wet seal all work he has done. The quality of some of his work is questionable – other work he does he seems to be qualified.

Without getting into the PE vs. SE debate in California, I only wish to know if anyone who has knowledge what the California Business and Professional Act has to say about the engineer convicted of a felony? I am cleaning up one of his messes now and have sent a copy of the problem to BORPELS to add to my previous complaint. BORPELS did contact the non-engineer to remind him that he can not operate a firm that is in his name and call it an engineering firm. Rather than have his full name in the Chapter S corporation firms local listings, he shortened it to his initials and BORPELS has left him alone. When I questioned this with the board they indicated that they were not going to come down on PE’s who advertise in the SE section of the phone book since they have attempted to remedy the section name in the Yellow pages and left as frustrated as most of use who are left with Civil or Consulting Engineer that restricts business. Furthermore, they believe that the advent of consulting firms that team up creates the potential for problems with the rules related to under direct supervision and have taken a step back on this to bring it up with the times. They feel that there is no way to enforce laws such as direct supervision when drawings can claim to be sent over the Internet and that this allows the lead engineer to review the work from an additional location. I am sure that providing a stamp and giving the authority to use it to a non-engineer in another office is not in the intent of the business code. However, the way they have delayed addressing this complaint the other party is the luckiest guy on earth.

Any comment or suggestion (interpretation of the code) would be greatly appreciated.

Dennis

Can an engineer practice with a felony conviction in California?

Any comment or suggestion (interpretation of the code) would be greatly appreciated.

Dennis

Re: Problem with SE Reference

Milo,

This is how I had to get some of my references for SE exam.

A simple Google search yields several structural engineering companies in Stockton - call them.

Good luck,

V. Steve Gordin, SE
Irvine CA

----- Original Message -----

From: Gerard Madden, SE

To: seaint@seaint.org

Sent: Saturday, June 16, 2007 13:51

Subject: Re: Problem with SE Reference

Check with your local SEAOC chapter. I here than can do that or supply a group to review some of you past work, but I dunno how long it takes or anyone who's ever gone down that route.

good luck.

-g

On 6/15/07, Zabala, Milo <mzabala@strocal.com> wrote:

I am preparing to take the SE exam in California this October and needs one more of the required 3 SE references. The PE board advised to show my documented work for review to a prospective referee, if satisfied he or she can sign on the reference form.

Is there anyone who may be willing to review my work and become a reference? Please HELP.

thks,

Milo Zabala, PE

Stockton, CA

--
-gm

Re: Problem with SE Reference

Check with your local SEAOC chapter. I here than can do that or supply a group to review some of you past work, but I dunno how long it takes or anyone who's ever gone down that route.

good luck.

-g

On 6/15/07, Zabala, Milo <mzabala@strocal.com> wrote:

I am preparing to take the SE exam in California this October and needs one more of the required 3 SE references. The PE board advised to show my documented work for review to a prospective referee, if satisfied he or she can sign on the reference form.

Is there anyone who may be willing to review my work and become a reference? Please HELP.

thks,

Milo Zabala, PE

Stockton, CA

--
-gm

Re: dead end slab control joint

IMHO concrete is smarter than we are. I've seen cracks only a couple of inches away from, and parallel to, a control joint. Who knows? I suspect that if the "control joint" isn't a complete cut through the full depth of the slab the crack will continue through the "T."

Good luck!

Ralph Hueston Kratz, S.E.
Richmond CA USA

In a message dated 6/16/07 12:16:06 PM, mpuccio@mpsqrd.com writes:

Is it wrong to detail a control joint to come to a "T"? I have a floor with geometry such that when I layout the control joint spacing it would work out good if this is okay or will the crack continue thru the T? I can't find any documentation one way or the other on this. I guess a safe thing to do would be to angle the cut or cut full depth – but I am wondering what some of your thoughts and experiences are.

Thanks,

Mark L. Puccio P.E., S.E.

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dead end slab control joint

Is it wrong to detail a control joint to come to a “T”? I have a floor with geometry such that when I layout the control joint spacing it would work out good if this is okay or will the crack continue thru the T? I can’t find any documentation one way or the other on this. I guess a safe thing to do would be to angle the cut or cut full depth – but I am wondering what some of your thoughts and experiences are.

Thanks,

Mark L. Puccio P.E., S.E.

Turn of the nut

Why not just use a DTI (Direct tension indicating) washer under the bolt head? I think you add an extra washer and then the gap is to be 5 thousands when tight. then you don't have to worry about the turn of the nut method. the washer will show you that is tensioned. I like the DTI Squirter type for easy inspection

Tim Rudolph

Bishop,CA

RE: Dumb Question

According to the dictionary, "rhetorical" means ...

[adj] concerned with effect or style of writing and speaking; "a rhetorical
question is one asked solely to produce an effect (especially to make an
assertion) rather than to elicit a reply".

This is my understanding. I.e. some sort of posed supposition, somewhat
unnecessary, but (possibly) a strategy to have someone else get involved in
the thought/idea without actually inviting them to be ...

I take it that Bill sees through that plot and, likewise, I have often
wondered (internally) why the question was even submitted ...

Thor T

-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com]
Sent: June 15, 2007 6:42 PM
To: seaint@seaint.org
Subject: Re: Dumb Question

On Jun 15, 2007, at 6:01 PM, Bill Allen wrote:

> Rhetorical questions.
>
> I hate those.
They only have one answer: 'I assume that's a rhetorical question.
Anyone else?'

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/~chrisw/

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: LL on roof with solar panels.

Gary,

If it is a sloping roof, I wouldn't concern myself with the added weight
assuming that the roof was orignially designed for a code required live
load. If it is a flat roof, I would check for both the required live load
and the new solar panel dead load combined. My logic is that the roof live
load would account for some unusual lodaing such as ponding water if a roof
drain clogged up.

Larry Hauer S.E.

>From: garyg@structuralstuff.com
>Reply-To: <seaint@seaint.org>
>To: seaint@seaint.org
>Subject: LL on roof with solar panels.
>Date: Fri, 15 Jun 2007 11:34:51 -0400 (EDT)
>
>
>When you have flat panel solar panels on a roof, is there still a need to
>apply the roof live load to the supporting members? I've always been
>taught that yes it would still be required but common sense says that since
>the solar panels are glass, it is unlikely that there will be any live load
>while the panels are in place.
>
>All opinions are welcome.
>
>Gary Grinstead, SE
>
>
>
>******* ****** ******* ******** ******* ******* ******* ***
>* Read list FAQ at: http://www.seaint.org/list_FAQ.asp
>*
>* This email was sent to you via Structural Engineers
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Friday, June 15, 2007

RE: turn of the nut

Make a few mock-ups from the material that you are tapping in a size that
you can put in a Skidmore. Put the mock-ups in a calibrated Skidmore and
measure the tension. Use the RCSC turn-of-the-nut method QC process.

Regards,
Harold Sprague

>From: raincat1@aol.com
>Reply-To: <seaint@seaint.org>
>To: seaint@seaint.org
>Subject: turn of the nut
>Date: Wed, 13 Jun 2007 19:29:09 -0400
>
>
>Say I have a tapped hole, and I needÂ full pre-tension on the bolt. How do
>I apply the "turn of the nut" method? How do I test representative samples
>as required by AISC? In this connection - I don't have a nut!
>
>Thanks !!
>
>
>Rainier C. Catubig
>San Diego, California
>
>
>
>
>________________________________________________________________________
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RE: Steel Properties for SAE 1045 at Higher Temperatures

Brian,
Take a look at ASME STS 1 Steel Stacks, Appendix B. Match the AISI SAE 1045
chemical composition to the ASTM chemical compositions listed in Appendix B.
They list mechanical properties relative to temperatures.

Regards,
Harold Sprague

>From: "Brian S Bossley" <BSBossley@venturaengineering.com>
>Reply-To: <seaint@seaint.org>
>To: <seaint@seaint.org>
>Subject: Steel Properties for SAE 1045 at Higher Temperatures
>Date: Fri, 15 Jun 2007 07:09:37 -0400
>
>I am in the process of analyzing a drum-type dryer at high temperatures
>(1000 degrees F), can anyone give me some guidance on where I would be
>able to find out how to figure out how the steel will behave at this
>temperature?
>
>
>
>Brian S Bossley, PE
>
>Ventura Engineering
>
>7610 Olentangy River Rd
>
>Columbus, OH 43235
>
>
>

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Re: Dumb Question

On Jun 15, 2007, at 6:01 PM, Bill Allen wrote:

> Rhetorical questions.
>
> I hate those.
They only have one answer: 'I assume that's a rhetorical question.
Anyone else?'

******* ****** ****** ****** ******* ****** ****** ********

Stability of block structure?

I am designing a free standing block structure that is in the shape of a
"C". It is approximately 15 feet tall. I want to run the steel horizontal on
the back of the "C" and have the legs of the "C" work as a cantilever from
the base.

How do I investigate the lateral stability of the legs? I know if it was
steel that I would have a buckling problem of a laterally unsupported edge.

TIA,

T. William (Bill) Allen, S.E.
ALLEN DESIGNS
Consulting Structural Engineers

Problem with SE Reference

I am preparing to take the SE exam in California this October and needs one more of the required 3 SE references. The PE board advised to show my documented work for review to a prospective referee, if satisfied he or she can sign on the reference form.

Is there anyone who may be willing to review my work and become a reference? Please HELP.

thks,

Milo Zabala, PE

Stockton, CA

RE: Dumb Question

The fourth type:

Rhetorical questions.

I hate those.

T. William (Bill) Allen, S.E.
ALLEN DESIGNS
Consulting Structural Engineers

> -----Original Message-----
> From: Christopher Wright [mailto:chrisw@skypoint.com]
> Sent: Friday, June 15, 2007 2:00 PM
> To: seaint@seaint.org
> Subject: Re: Dumb Question
>
>
> On Jun 15, 2007, at 2:08 PM, Bill Cain wrote:
>
> > Regarding your subject line, a colleague of mine frequently says:
> > "the only dumb question is the one that doesn't get asked!" I
> > strongly agree.
> I'll quibble with this. I've heard plenty of dumb questions. Mostly
> they can be categorized as questions which allow more than one
> correct answer (What kind of panda eats shoots and leaves?) and asked
> by someone who doesn't understand enough to sort out which answer is
> useful. Another category of dumb question is one that isn't
> researched well enough to allow the questioner to distinguish a wrong
> or incomplete answer from a correct answer. (Can I weld stainless
> steel?) There's a really good web site 'How to ask questions the
> Smart Way <http://www.catb.org/~esr/faqs/smart-questions.html> that
> explains how not to ask dumb questions.
>
> There's actually a third type of dumb question--sharpshooting.
> Questions which attempt to score points on a speaker wastes
> everyone's time and may get the questioner a public verbal smack in
> the mouth when the speaker knows his stuff.
>
> Christopher Wright P.E. |"They couldn't hit an elephant at
> chrisw@skypoint.com | this distance" (last words of Gen.
> .......................................| John Sedgwick, Spotsylvania
> 1864)
> http://www.skypoint.com/~chrisw/
>
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
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> *
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> *
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Re: Dumb Question

On Jun 15, 2007, at 2:08 PM, Bill Cain wrote:

> Regarding your subject line, a colleague of mine frequently says:
> "the only dumb question is the one that doesn't get asked!" I
> strongly agree.
I'll quibble with this. I've heard plenty of dumb questions. Mostly
they can be categorized as questions which allow more than one
correct answer (What kind of panda eats shoots and leaves?) and asked
by someone who doesn't understand enough to sort out which answer is
useful. Another category of dumb question is one that isn't
researched well enough to allow the questioner to distinguish a wrong
or incomplete answer from a correct answer. (Can I weld stainless
steel?) There's a really good web site 'How to ask questions the
Smart Way <http://www.catb.org/~esr/faqs/smart-questions.html> that
explains how not to ask dumb questions.

There's actually a third type of dumb question--sharpshooting.
Questions which attempt to score points on a speaker wastes
everyone's time and may get the questioner a public verbal smack in
the mouth when the speaker knows his stuff.

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RE: Dumb Question

:^)

I did mean to write ".../100ft^2"

-----Original Message-----
From: Bill Cain [mailto:bcainse@aol.com]
Sent: June 15, 2007 12:09 PM
To: seaint@seaint.org
Subject: Re: Dumb Question

Thor-

90#/Roofing Square which is 90# per 100 Square feet = 0.9 psf

Regarding your subject line, a colleague of mine frequently says: "the only dumb question is the one that doesn't get asked!" I strongly agree.

Re: LL on roof with solar panels.

Good points, Daryl. When I'm on a roof, I take up at least 10 square feet of LLr...if there's only a foot between panels, do I need to lie down so that I spread my load out linearly?

Let me add - what happens if a future owner decides to remove the panels? This is not some far-out hypothetical, like "what if the new owner decides to put on an intensive green roof." In this case , the panels are removed and no load study would even be considered since the new owner would be removing weight.

Where I am, snow load (25-30 psf ground) always controls over roof live, and snow needs to be added to any roof fixtures, though the load path may change. You might also check for snow drifts occurring under the panels if you have a roof step or ridge anywhere and you're in snow country. That check might also cover the LLr case.

Jordan

Daryl Richardson wrote:

Gary,

        There are three possible load cases you should think about. These are:

1.)    Workers who might be working on the roof plus stacked materials while they're working. I think the code specifies a minimum of 1.0 kPa (20.7 p.s.f) to account for this.

2.)    What happens if you get a big dump of snow overnight? As a presumption of reasonableness (not a code requirement) I would suggest about 50% of the design snow load as a minimum.

3.)    What about snow load while the owners/caretakers are on vacation? My preference would be to design for the normal snow load. Better safe than sorry>

Regards,

H. Daryl Richardson

----- Orig
** ****** ****** ********

Re: Dumb Question

Thor-

90#/Roofing Square which is 90# per 100 Square feet = 0.9 psf

Regarding your subject line, a colleague of mine frequently says: "the only dumb question is the one that doesn't get asked!" I strongly agree.

Regards,

Bill Cain SE

Berkeley CA

-----Original Message-----
From: Thor Tandy
To: SEAINT
Sent: Fri, 15 Jun 2007 9:27 am
Subject: Dumb Question

90lb roof felt!  Am I right in taking the material weight to be 90lb/ft^2?  Thanks  Thor T  ******* ****** ******* ******** ******* ******* ******* *** *   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: LL on roof with solar panels.

Gary,

There are three possible load cases you should think about. These are:

1.) Workers who might be working on the roof plus stacked materials while they're working. I think the code specifies a minimum of 1.0 kPa (20.7 p.s.f) to account for this.

2.) What happens if you get a big dump of snow overnight? As a presumption of reasonableness (not a code requirement) I would suggest about 50% of the design snow load as a minimum.

3.) What about snow load while the owners/caretakers are on vacation? My preference would be to design for the normal snow load. Better safe than sorry>

Regards,

H. Daryl Richardson

----- Original Message -----

From: garyg@structuralstuff.com

To: seaint@seaint.org

Sent: Friday, June 15, 2007 11:51 AM

Subject: RE: LL on roof with solar panels.

My question is not whether to treat the panels as live load but rather if there is a need to apply the roof live load in the area where the panels are to be installed. The panel weight is 3 psf which is typical but the spacing between rail supports is up to 8 feet. This is what has me concerned with the application of roof live load over the panels which would place a fairly hefty concentrated load on the existing roof trusses.

-----Original Message-----
From: William King
Sent: Fri, June 15, 2007 12:50 pm
To: seaint@seaint.org
Subject: RE: LL on roof with solar panels.

The definition for Live Load for the I-codes would be the same. Fixed equipment is a dead load.

You would still need to apply the live load to even the area covered by the panels as there may be people on the roof at times maintaining the panels.

-Bill King, PE, MCP

From: Mark E. Deardorff [mailto:mdeardorff@burkett-wong.com]
Sent: Friday, June 15, 2007 12:39 PM
To: seaint@seaint.org
Subject: RE: LL on roof with solar panels.

You can't take it as live load, at least not under the 1997 UBC. Table 16-B lists mechanical and electrical equipment with the parenthetical "(dead load)". You still end up with the 0.9 load duration factor though.

Mark E. Deardorff, S.E.

Structural Engineer

3434 4th Ave

San Diego, CA 92103

P 619.299.5550

F 619.299.9934

mdeardorff@burkett-wong.com

From: Bill Cain [mailto:bcainse@aol.com]
Sent: Friday, June 15, 2007 9:27 AM
To: seaint@seaint.org
Subject: Re: LL on roof with solar panels.

Gary-

Assuming your roof is wood frame, if you treat solar panels as the Live Load, you should increase the Solar panel load by a duration factor of 1/0.9 to account for the fact the load is likely longer duration than the 10 years assumed for LL per Nds. Most, including mine, are warranted for about 25 years.

It is not likely to be a problem with the usual weight of the panels in the 3-4 psf range. Normal Code Live load (without solar load) should also be checked without the solar panel load (with a duration factor for wood construction of 1.25) to allow for installation loads similar to the way roofing loads are treated.

Regards,
Bill Cain SE
Berkeley CA

-----Original Message-----
From: garyg@structuralstuff.com
To: seaint@seaint.org
Sent: Fri, 15 Jun 2007 8:34 am
Subject: LL on roof with solar panels.

When you have flat panel solar panels on a roof, is there still a need to apply the roof live load to the supporting members? I've always been taught that yes it would still be required but common sense says that since the solar panels are glass, it is unlikely that there will be any live load while the panels are in place.

All opinions are welcome.

Gary Grinstead, SE

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RE: Dumb Question

Roofing materials' weights are given per "square", and in roofing
parlance, a square is 10Ft. x 10Ft. or 100 Sq. Ft. Typical composition
tab shingles are 235 Lb. per square and are typically furnished in 1/3
square bundles, so it takes 3 bundles per square. Go out and impress
your roofer.

Bob Garner

-----Original Message-----
From: Thor Tandy [mailto:vicpeng@telus.net]
Sent: Friday, June 15, 2007 9:28 AM
To: SEAINT
Subject: Dumb Question

90lb roof felt! Am I right in taking the material weight to be
90lb/ft^2?

Thanks

Thor T

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RE: LL on roof with solar panels.

My question is not whether to treat the panels as live load but rather if there is a need to apply the roof live load in the area where the panels are to be installed. The panel weight is 3 psf which is typical but the spacing between rail supports is up to 8 feet. This is what has me concerned with the application of roof live load over the panels which would place a fairly hefty concentrated load on the existing roof trusses.

-----Original Message-----
From: William King
Sent: Fri, June 15, 2007 12:50 pm
To: seaint@seaint.org
Subject: RE: LL on roof with solar panels.

The definition for Live Load for the I-codes would be the same. Fixed equipment is a dead load.

You would still need to apply the live load to even the area covered by the panels as there may be people on the roof at times maintaining the panels.

-Bill King, PE, MCP

From: Mark E. Deardorff [mailto:mdeardorff@burkett-wong.com]
Sent: Friday, June 15, 2007 12:39 PM
To: seaint@seaint.org
Subject: RE: LL on roof with solar panels.

You can't take it as live load, at least not under the 1997 UBC. Table 16-B lists mechanical and electrical equipment with the parenthetical "(dead load)". You still end up with the 0.9 load duration factor though.

Mark E. Deardorff, S.E.

Structural Engineer

3434 4th Ave

San Diego, CA 92103

P 619.299.5550

F 619.299.9934

mdeardorff@burkett-wong.com

From: Bill Cain [mailto:bcainse@aol.com]
Sent: Friday, June 15, 2007 9:27 AM
To: seaint@seaint.org
Subject: Re: LL on roof with solar panels.

Gary-

Assuming your roof is wood frame, if you treat solar panels as the Live Load, you should increase the Solar panel load by a duration factor of 1/0.9 to account for the fact the load is likely longer duration than the 10 years assumed for LL per Nds. Most, including mine, are warranted for about 25 years.

It is not likely to be a problem with the usual weight of the panels in the 3-4 psf range. Normal Code Live load (without solar load) should also be checked without the solar panel load (with a duration factor for wood construction of 1.25) to allow for installation loads similar to the way roofing loads are treated.

Regards,
Bill Cain SE
Berkeley CA

-----Original Message-----
From: garyg@structuralstuff.com
To: seaint@seaint.org
Sent: Fri, 15 Jun 2007 8:34 am
Subject: LL on roof with solar panels.

When you have flat panel solar panels on a roof, is there still a need to apply the roof live load to the supporting members? I've always been taught that yes it would still be required but common sense says that since the solar panels are glass, it is unlikely that there will be any live load while the panels are in place.

All opinions are welcome.

Gary Grinstead, SE

******* ****** ******* ******** ******* ******* ******* *** * 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 y ou visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********

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******* ****** ******* ******** ******* ******* ******* *** * 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 ******* ****** ****** ****** ******* ****** ****** ********

RE: LL on roof with solar panels.

The definition for Live Load for the I-codes would be the same. Fixed equipment is a dead load.

You would still need to apply the live load to even the area covered by the panels as there may be people on the roof at times maintaining the panels.

-Bill King, PE, MCP

From: Mark E. Deardorff [mailto:mdeardorff@burkett-wong.com]
Sent: Friday, June 15, 2007 12:39 PM
To: seaint@seaint.org
Subject: RE: LL on roof with solar panels.

Mark E. Deardorff, S.E.

Structural Engineer

3434 4th Ave

San Diego, CA 92103

P 619.299.5550

F 619.299.9934

mdeardorff@burkett-wong.com

From: Bill Cain [mailto:bcainse@aol.com]
Sent: Friday, June 15, 2007 9:27 AM
To: seaint@seaint.org
Subject: Re: LL on roof with solar panels.

Gary-

Assuming your roof is wood frame, if you treat solar panels as the Live Load, you should increase the Solar panel load by a duration factor of 1/0.9 to account for the fact the load is likely longer duration than the 10 years assumed for LL per Nds. Most, including mine, are warranted for about 25 years.

It is not likely to be a problem with the usual weight of the panels in the 3-4 psf range. Normal Code Live load (without solar load) should also be checked without the solar panel load (with a duration factor for wood construction of 1.25) to allow for installation loads similar to the way roofing loads are treated.

Regards,
Bill Cain SE
Berkeley CA

-----Original Message-----
From: garyg@structuralstuff.com
To: seaint@seaint.org
Sent: Fri, 15 Jun 2007 8:34 am
Subject: LL on roof with solar panels.

When you have flat panel solar panels on a roof, is there still a need to apply the roof live load to the supporting members? I've always been taught that yes it would still be required but common sense says that since the solar panels are glass, it is unlikely that there will be any live load while the panels are in place.

All opinions are welcome.

Gary Grinstead, SE

******* ****** ******* ******** ******* ******* ******* *** * 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: LL on roof with solar panels.

Mark E. Deardorff, S.E.

Structural Engineer

3434 4th Ave

San Diego, CA 92103

P 619.299.5550

F 619.299.9934

mdeardorff@burkett-wong.com

From: Bill Cain [mailto:bcainse@aol.com]
Sent: Friday, June 15, 2007 9:27 AM
To: seaint@seaint.org
Subject: Re: LL on roof with solar panels.

Gary-

Assuming your roof is wood frame, if you treat solar panels as the Live Load, you should increase the Solar panel load by a duration factor of 1/0.9 to account for the fact the load is likely longer duration than the 10 years assumed for LL per Nds. Most, including mine, are warranted for about 25 years.

It is not likely to be a problem with the usual weight of the panels in the 3-4 psf range. Normal Code Live load (without solar load) should also be checked without the solar panel load (with a duration factor for wood construction of 1.25) to allow for installation loads similar to the way roofing loads are treated.

Regards,
Bill Cain SE
Berkeley CA

-----Original Message-----
From: garyg@structuralstuff.com
To: seaint@seaint.org
Sent: Fri, 15 Jun 2007 8:34 am
Subject: LL on roof with solar panels.

When you have flat panel solar panels on a roof, is there still a need to apply the roof live load to the supporting members? I've always been taught that yes it would still be required but common sense says that since the solar panels are glass, it is unlikely that there will be any live load while the panels are in place.

All opinions are welcome.

Gary Grinstead, SE

******* ****** ******* ******** ******* ******* ******* *** * 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: Dumb Question

No. That is 90# per 100 sq ft. So 0.9 psf.

Mark E. Deardorff, S.E.
Structural Engineer
Burkett & Wong Engineers
3434 4th Ave
San Diego, CA 92103
P 619.299.5550
F 619.299.9934
mdeardorff@burkett-wong.com

> -----Original Message-----
> From: Thor Tandy [mailto:vicpeng@telus.net]
> Sent: Friday, June 15, 2007 9:28 AM
> To: SEAINT
> Subject: Dumb Question
>
> 90lb roof felt! Am I right in taking the material weight to
> be 90lb/ft^2?
>
> Thanks
>
> Thor T
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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: Dumb Question

-----Original Message-----
From: Thor Tandy [mailto:vicpeng@telus.net]
Sent: June 15, 2007 9:28 AM
To: SEAINT
Subject: Dumb Question

90lb roof felt! Am I right in taking the material weight to be
90lb/100ft^2?

Thanks

Thor T

******* ****** ****** ****** ******* ****** ****** ********

Dumb Question

90lb roof felt! Am I right in taking the material weight to be 90lb/ft^2?

Thanks

Thor T

******* ****** ****** ****** ******* ****** ****** ********

Re: LL on roof with solar panels.

Gary-

Assuming your roof is wood frame, if you treat solar panels as the Live Load, you should increase the Solar panel load by a duration factor of 1/0.9 to account for the fact the load is likely longer duration than the 10 years assumed for LL per Nds. Most, including mine, are warranted for about 25 years.

It is not likely to be a problem with the usual weight of the panels in the 3-4 psf range. Normal Code Live load (without solar load) should also be checked without the solar panel load (with a duration factor for wood construction of 1.25) to allow for installation loads similar to the way roofing loads are treated.

Regards,
Bill Cain SE
Berkeley CA

-----Original Message-----
From: garyg@structuralstuff.com
To: seaint@seaint.org
Sent: Fri, 15 Jun 2007 8:34 am
Subject: LL on roof with solar panels.

When you have flat panel solar panels on a roof, is there still a need to apply the roof live load to the supporting members? I've always been taught that yes it would still be required but common sense says that since the solar panels are glass, it is unlikely that there will be any live load while the panels are in place.

All opinions are welcome.

Gary Grinstead, SE

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Re: Steel Properties for SAE 1045 at Higher Temperatures

On Jun 15, 2007, at 6:09 AM, Brian S Bossley wrote:

> I am in the process of analyzing a drum-type dryer at high
> temperatures (1000 degrees F), can anyone give me some guidance on
> where I would be able to find out how to figure out how the steel
> will behave at this temperature?
Typically carbon steel isn't used above 800 or 900 deg because you're
starting into the creep range. There are also some metallurgical
changes that take place in addition to alteration of properties
attained by heat treatment. I did some checking around in ASME/ASTM
material specs and didn't find anything like design properties, I
expect because the mechanical properties vary so much with cold work
and thermal treatment.

Your best bet is likely to be the ASM Metals Handbook, but don't
expect design properties--_Metals Handbook_ generally addresses
metallurgy, including typical mechanical properties. There are ASTM
specs for carbon steel bars with room temperature mechanical
properties in various conditions that might allow you to infer high
temperature behavior from the ASME Code allowables, but you'll have
to do some digging.

You haven't mentioned welding, but it's never a good idea with 1045,
and an even worse idea for machinery.

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RE: LL on roof with solar panels.

I do not apply live load in the areas that the panels are concealing.

Mark E. Deardorff, S.E.

Structural Engineer

3434 4th Ave

San Diego, CA 92103

P 619.299.5550

F 619.299.9934

mdeardorff@burkett-wong.com

From: garyg@structuralstuff.com [mailto:garyg@structuralstuff.com]
Sent: Friday, June 15, 2007 8:35 AM
To: seaint@seaint.org
Subject: LL on roof with solar panels.

When you have flat panel solar panels on a roof, is there still a need to apply the roof live load to the supporting members? I've always been taught that yes it would still be required but common sense says that since the solar panels are glass, it is unlikely that there will be any live load while the panels are in place.

All opinions are welcome.

Gary Grinstead, SE

******* ****** ******* ******** ******* ******* ******* *** * 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 ******* ****** ****** ****** ******* ****** ****** ********