Structural Engineering: 2008-08-03

Friday, August 8, 2008

RE: ASCE 7 Wind Gust Effect Factor

This is consistant with what was offered at some session on the wind provisions of ASCE 7 at the Structures Congress in Long Beach by an ASCE 7 Wind "Expert"...the vast majority of buildings would end up with a gust factor of 0.85. Of course, my one exposure to the hot air blowing from section 6.5.8 (yes, pun intended) was for doing a sign...not a building. Let's just say that for that little exercise in "fun", it made me seriously question my dislike of beer...some liquid lubrication would have likely made that experience MUCH more pleasant. Several hours of looking at that gibberish/witchcraft tended to make me want to beat the crap out of someone....especially since I used to be able to get a wind pressure/force for a sign from the BOCA code in about 30 seconds.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: David Topete [mailto:d.topete73@gmail.com]
Sent: Friday, August 08, 2008 5:10 PM
To: seaint@seaint.org
Subject: Re: ASCE 7 Wind Gust Effect Factor

A beer or two makes most things funner...

Using a gust effect factor of 0.85 seems conservative to most applications. try setting up a spreadsheet. i have a mathcad sheet set up from my last p.o.e. Let me see if i can find an excel sheet.

On Fri, Aug 8, 2008 at 1:42 PM, Scott Maxwell <smaxwell@umich.edu> wrote:

You don't want to do it per 6.5.8? But, there so many pretty forumulas and wonderfully variable variables! <grin> Such witchcraft is meant to be fun!

And yes, I am being sarcastic.

FWIW, it is not too bad, if you have several hours to kill. I suppose that if I drank beer, a few beers would likely make it more enjoyable. :-)

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Garner, Robert [mailto:rgarner@moffattnichol.com]
Sent: Friday, August 08, 2008 2:42 PM
To: seaint@seaint.org

Subject: ASCE 7 Wind Gust Effect Factor

I am analyzing a tower type building using the Analytical Procedure, which requires the divination of the Gust Effect Factor. ASCE Paragraph 6.5.8.3 graciously allows the use "any rational analysis defined in the recognized literature" as an alternate to the witchcraft required in 6.5.8.

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

I think Doug Adams came up with the answer to the question of the universe as 42. Supposedly, after they finally found this answer, they forgot the question. The world can now thank me for I have discovered that the question is "What is the gust effect factor".

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

--
David Topete, SE

Re: wind on stair tower

Andrew

I'm going to try to reply from my "Crackberry" as I'm out of town. I am doing a proposal for the fabricator. The stairtower is only attached to the garage at the landings and some cross beams supporting the stringers. Other than that it will be self supporting. The parking garage wraps around the tower on two sides, but is only attached to the garage at the landings along one of those two sides. The stringers wrap around two HSS columns. I'm holding off on my proposal until Monday as the fabricator found further information regarding the soils and foundation and possibly loading to the connections to the parking structure. The stair towers were designed originally by the garage design engineers, but the fabricator wants to do a design/build on the stairs as they didn't like the existing layout. Ill try to get more info nerxt week.

Joe Grill

Sent from my Verizon Wireless BlackBerry

From: "Andrew Kester, P.E." <akester@cfl.rr.com>
Date: Fri, 8 Aug 2008 17:36:24 -0400
To: seaint<seaint@seaint.org>
Subject: re: wind on stair tower

Joe,

We have done a few somewhat similar projects, such as a belltower for a church that had open portions but was mainly enclosed, free standing and not supported by the building.

This is my gut feeling without studying ASCE or your dwgs... You said it will be supported partially by the parking garage on one side, and then I assume at the outside by two vertical HSS sections that will make up part of a braced or moment frame? I would treat it as part of the building as far as any importance factor or anything is concerned, and your building department will probably like that also as it is a means of egress. But not for wind.

For wind loading you said it will be enclosed by parking structure on two sides, but you also say there will be a screening material? I am not sure I fully understand what this is all looking like, but I think the lateral pressures I would compare are that of a free standing wall and then that of a tower. As it will not likely make any appreciable cost difference on something this size, I would go with the worse case of the two. The stairs themselves will also have a vertical projection surface, probably more so than the rest of the structure.

If you wanted to get creative you could use the stair stringers and landings as a series of diagonal braces, but since these are probably supplied by the steel fabricator and engineered by them I think I would design this with X braces on the outside frame (if the arch OKs it). But sleep well knowing that your stairs will act as additional bracing (especially if these are steel stringers with steel pans filled with concrete)...

HTH,

Andrew

re: wind on stair tower

Joe,

We have done a few somewhat similar projects, such as a belltower for a church that had open portions but was mainly enclosed, free standing and not supported by the building.

HTH,

Andrew

Re: ASCE 7 Wind Gust Effect Factor

A beer or two makes most things funner...

Using a gust effect factor of 0.85 seems conservative to most applications. try setting up a spreadsheet. i have a mathcad sheet set up from my last p.o.e. Let me see if i can find an excel sheet.

On Fri, Aug 8, 2008 at 1:42 PM, Scott Maxwell <smaxwell@umich.edu> wrote:

You don't want to do it per 6.5.8? But, there so many pretty forumulas and wonderfully variable variables! <grin> Such witchcraft is meant to be fun!

And yes, I am being sarcastic.

FWIW, it is not too bad, if you have several hours to kill. I suppose that if I drank beer, a few beers would likely make it more enjoyable. :-)

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Garner, Robert [mailto:rgarner@moffattnichol.com]
Sent: Friday, August 08, 2008 2:42 PM
To: seaint@seaint.org

Subject: ASCE 7 Wind Gust Effect Factor

I am analyzing a tower type building using the Analytical Procedure, which requires the divination of the Gust Effect Factor. ASCE Paragraph 6.5.8.3 graciously allows the use "any rational analysis defined in the recognized literature" as an alternate to the witchcraft required in 6.5.8.

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

I think Doug Adams came up with the answer to the question of the universe as 42. Supposedly, after they finally found this answer, they forgot the question. The world can now thank me for I have discovered that the question is "What is the gust effect factor".

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

--
David Topete, SE

RE: ASCE 7 Wind Gust Effect Factor

Speaking of beer (and it being beer-thirty Friday), I found some Leinenkugels (sp?) at my local BevMo and decided to give it a try based on the recommendations from this here list. I have to say it was…ok. It is an impressively aromatic and flavorful beer, which, for me, was its strength and weakness. It is very unique and I could see drinking it in certain situations, but it didn’t work for me as a regular drinking beer. Regardless, I enjoyed the experience of trying it.

Cheers,

Doug Mayer, SE

Structural Engineer

From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Friday, August 08, 2008 1:43 PM
To: seaint@seaint.org
Subject: RE: ASCE 7 Wind Gust Effect Factor

You don't want to do it per 6.5.8? But, there so many pretty forumulas and wonderfully variable variables! <grin> Such witchcraft is meant to be fun!

And yes, I am being sarcastic.

FWIW, it is not too bad, if you have several hours to kill. I suppose that if I drank beer, a few beers would likely make it more enjoyable. :-)

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Garner, Robert [mailto:rgarner@moffattnichol.com]
Sent: Friday, August 08, 2008 2:42 PM
To: seaint@seaint.org
Subject: ASCE 7 Wind Gust Effect Factor

I am analyzing a tower type building using the Analytical Procedure, which requires the divination of the Gust Effect Factor. ASCE Paragraph 6.5.8.3 graciously allows the use "any rational analysis defined in the recognized literature" as an alternate to the witchcraft required in 6.5.8.

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

I think Doug Adams came up with the answer to the question of the universe as 42. Supposedly, after they finally found this answer, they forgot the question. The world can now thank me for I have discovered that the question is "What is the gust effect factor".

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

re: ABs...

Thanks to Harold, Bill and Suresh for your discussion on ACI anchor bolts. Though at first it is a bit against my engineering common sense, I know understand what you mean when you say that bearing plates can actually REDUCE the pullout strength of the anchor bolts. Very interesting, call me a flip flopper but I have been convinced, and will no longer specify the oversized washers or bearing plates, just an unnecessary additional expense, though tiny. FWIW, I always design based on only the bolt head or nut, and just treated the plate as a feather in my cap, but as it turns out that doesn't really help.

Have a good weekend all,

Andrew

Andrew Kester, PE
Principal/Project Manager
ADK Structural Engineering, PLLC
1510 E. Colonial Ave., Suite 301
Orlando, FL 32803

RE: ASCE 7 Wind Gust Effect Factor

You don't want to do it per 6.5.8? But, there so many pretty forumulas and wonderfully variable variables! <grin> Such witchcraft is meant to be fun!

And yes, I am being sarcastic.

FWIW, it is not too bad, if you have several hours to kill. I suppose that if I drank beer, a few beers would likely make it more enjoyable. :-)

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Garner, Robert [mailto:rgarner@moffattnichol.com]
Sent: Friday, August 08, 2008 2:42 PM
To: seaint@seaint.org
Subject: ASCE 7 Wind Gust Effect Factor

I am analyzing a tower type building using the Analytical Procedure, which requires the divination of the Gust Effect Factor. ASCE Paragraph 6.5.8.3 graciously allows the use "any rational analysis defined in the recognized literature" as an alternate to the witchcraft required in 6.5.8.

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

I think Doug Adams came up with the answer to the question of the universe as 42. Supposedly, after they finally found this answer, they forgot the question. The world can now thank me for I have discovered that the question is "What is the gust effect factor".

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

RE: ASCE 7 Wind Gust Effect Factor

Thanks, Dave. Yes that helps and I should have been astute enough to look that up myself. But having read the titles and authors of those references, I think I would like to find something written by a practicing engineer.

Bob

From: David Topete [mailto:d.topete73@gmail.com]
Sent: Friday, August 08, 2008 12:09 PM
To: seaint@seaint.org
Subject: Re: ASCE 7 Wind Gust Effect Factor

In the commentary (pg 293 of ASCE 7-05), the recognized literature is references C6-42 through C6-47. those appear to be various journal articles. see pg 304. HTH.

On Fri, Aug 8, 2008 at 11:41 AM, Garner, Robert <rgarner@moffattnichol.com> wrote:

I am analyzing a tower type building using the Analytical Procedure, which requires the divination of the Gust Effect Factor. ASCE Paragraph 6.5.8.3 graciously allows the use "any rational analysis defined in the recognized literature" as an alternate to the witchcraft required in 6.5.8.

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

I think Doug Adams came up with the answer to the question of the universe as 42. Supposedly, after they finally found this answer, they forgot the question. The world can now thank me for I have discovered that the question is "What is the gust effect factor".

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

--
David Topete, SE

Re: ASCE 7 Wind Gust Effect Factor

In the commentary (pg 293 of ASCE 7-05), the recognized literature is references C6-42 through C6-47. those appear to be various journal articles. see pg 304. HTH.

On Fri, Aug 8, 2008 at 11:41 AM, Garner, Robert <rgarner@moffattnichol.com> wrote:

I am analyzing a tower type building using the Analytical Procedure, which requires the divination of the Gust Effect Factor. ASCE Paragraph 6.5.8.3 graciously allows the use "any rational analysis defined in the recognized literature" as an alternate to the witchcraft required in 6.5.8.

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

I think Doug Adams came up with the answer to the question of the universe as 42. Supposedly, after they finally found this answer, they forgot the question. The world can now thank me for I have discovered that the question is "What is the gust effect factor".

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

--
David Topete, SE

ASCE 7 Wind Gust Effect Factor

Does anyone have any recommendations for recognized literature that can serve as an alternate to compute this highly mystical factor?

Thanks for your help.

Bob Garner, S.E.

R. Garner

Moffatt & Nichol

Tel.: (619) 220-6050

Fax.: (619) 220-6055

e-mail: rgarner@moffattnichol.com

RE: seaint Digest for 7 Aug 2008

Joe, if it is a means of egress for the parking structure, it must be
designed for the full menu of building loads. It is not uncommon to
"unhook" stair towers from parking structures because they expand and
contract more than a conventional building structure due to exposure to
the full temperature swing of the environment, and it must either be
detailed to "go along for the ride" or be independent to mitigate that
effect, and they certainly should not impart restraint to the parking
structure expansion and contraction. Durability is also a concern, so in
my humble opinion, I would treat it as an enclosed or partially enclosed
building structure.......

Richard W. Stone, P.E.
Project Executive
Technical Services/Project Management/Estimating
Concept Design/Engineering/Quality Assurance

Madison Concrete Construction Company
130 Quaker lane
Malvern, PA 19355-2479
email: rstone@madisonconcrete.com
Voice: 610.695.8800
Facsimile: 610.695.8678

From: "Joseph R. Grill" <jrgrill@cableone.net>
To: <seaint@seaint.org>
Subject: wind on stair tower

This is a multipart message in MIME format.

------=_NextPart_000_0001_01C8F85D.A685E960
Content-Type: text/plain;
charset="us-ascii"
Content-Transfer-Encoding: 7bit

I have been asked to look at a free standing stair tower situated next
to a parking garage. The tower will be enclosed by the parking
structure on two sides and is about 30ft tall. It will be enclosed by a
screening material ("Green Screen" I believe it is called). I may be
able to take some of the wind loads into the parking structure, but I
think at this time, the remainder will be resisted by 2 vertical HSS
sections. I have some questions regarding the calculations for the wind
loading. What do you think, would this be a building or non-building
structure. If building, would it be enclosed, open, or partially
enclosed? If non building, would it be a tower, trussed tower or
whatever ? I'm sorry, it seems that I am asking about the entire setup
for the calculations, and I guess I am in a way. It doesn't seem as
though it really fits any of the definitions in ASCE 7-05. Maybe some
of you can explain a little. Any one done something like this in the
past?

Thanks,

Joe Grill

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

Ward R Malisch/ACI/Notes is out of the office.

I will be out of the office starting 08/08/2008 and will not return until
08/15/2008.

I hope to be responding to e-mail by June 14. If you need an immediate
response, please contact Bill Tolley, Dan Falconer, Rich Heitzmann, or
Diane Baloh. Their e-mail addresses are shown on the ACI Website
(www.concrete.org).

Thursday, August 7, 2008

RE: Large diameter bolt clearances

Bill,

I recollect someone providing a link to an AISC document a few weeks back describing inconsistencies in clearances between the steel and concrete specifications (US), and making recommendations to resolve. I can’t remember the link, but you could search the AISC website.

Here it is typically 2mm clearance in general, 4mm for base plates, and I think up to 6mm for larger bolts in base plates: assuming you are referring to bolt hole clearance. For using an impact wrench typically need at least 55mm clearance from any face, and recommended minimum of 100mm between faces if hand access required, if the issues are clearance for tooling and access.

Regards

Conrad Harrison

B.Tech (mfg & mech), MIIE, gradTIEAust

mailto:sch.tectonic@bigpond.com

Adelaide

South Australia

From: William.Sherman@CH2M.com [mailto:William.Sherman@CH2M.com]
Sent: Friday, 8 August 2008 07:31
To: seaint@seaint.org
Subject: Large diameter bolt clearances

Any suggestions for references for tightening clearance requirements for large diameter anchor bolts (>1.25" diameter)?

Bill

William Sherman - CH2M HILL / Denver

Principal Structural Technologist

Structural Global Technology Leader - Water Business Group

william.sherman@ch2m.com

720.286.2792

RE: Water Tanks

Thanks David,

Actually the only reason we got involved with the tanks, is because a wind
storm picked up a newly installed empty tank, and threw it over the top of a
hill. Typically here in SA, domestic rainwater tanks, don't need development
approval, which generally also means no engineering evaluation. The tanks
have otherwise been in use for years, and barring being picked up by the
wind: are generally sufficient for purpose. The builders have no problems or
issues regarding being on the roof whilst constructing.

For some reason the tanks are now going through development approval:
possibly because of increased footprint. The tanks are available in a range
of sizes. Since the tanks already exist all over the place the objective has
to be to demonstrate the tanks have acceptable performance. However we have
no mandatory code defining acceptability. I'm not doing the design, just
seeking information to pass on: but checking the wind loading was the first
issue checked, and the corrugated skirt was also checked as a tank wall:
which as I say the wall is largely there to hide what is otherwise a big
plastic bag. I believe an American water association code was used for part
of the assessment of the skirt as a tank. Some modifications have been
imposed on the design to address the wind loading problem.

The roof over the tank was described as a cover. The tank is round, and the
cover comprises a series of trusses, parallel to one another rather than
radial, then corrugated steel cladding is sprung over to form a dome. Since
roof live loading wasn't an issue, the reactions from were not transferred
to the steel skirt. The question has thus arisen whether the steel skirt can
support the loads. History shows the walls can support real world loads.

Testing maybe the best approach, but with a range of different tank sizes,
such may not be practical in the short term. Adding extra roof supports may
be acceptable for the current project seeking approval, but really need to
demonstrate that the current design is adequate. Or find the limitations of
the steel skirt to support the roof load, and thus when additional roof
supports do need to be provided. (Fortunately we don't have snow.)

Since any portion of the wall is restrained by adjacent wall, it seems like
a complicated problem. Treating a portion of the wall as a simple column is
too unrealistic, it will simply generate a need for additional support:
conservative for design but poor assessment.

We also want to avoid using FEM software, which I don't believe can check
buckling in any case. What we are looking for is a code of practice or
specification with simple empirical rules.

Failing that I guess we will have to recommend some testing. Which I guess
is not too difficult, applying a known point load to the top edge of the
skirt. For the most part I believe localised deformation of the edge of the
sheet is more the issue than collapse of the wall. It's just a problem of
proving it. Easier said than done.

Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic@bigpond.com
Adelaide
South Australia

Large diameter bolt clearances

Any suggestions for references for tightening clearance requirements for large diameter anchor bolts (>1.25" diameter)?

Bill

William Sherman - CH2M HILL / Denver

Principal Structural Technologist

Structural Global Technology Leader - Water Business Group

william.sherman@ch2m.com

720.286.2792

RE: plywood diaphragm to light gage

Try ER 5380

Reza Dashti P.Eng
Vacouver, BC

________________________________________
> From: Joseph R. Grill [jrgrill@cableone.net]
> Sent: Thursday, July 31, 2008 11:22 AM
> To: seaint@seaint.org
> Subject: plywood diaphragm to light gage
>
> Several years ago I believe I ask a question of the list to see if there was any
> diaphragm values for plywood screwed to light gage supports. If I remember
> correctly, someone posted some ICBO testing (maybe ICC is newer) that contained
> diaphragm values. It may have been shot pins, I just don't remember. I have
> searched through my library, but since my office has moved a couple of times
> since then I can't find that information (if it existed in the first place). If
> anyone out there has that information, I would appreciate a copy or a link to
> the information. I have a client that is considering a roof system that would
> require this, if possible.
>
> Thanks,
> Joe Grill
>
> Joseph R. Grill, PE
> Verde Valley Engineering, PLLC
> 2220 Sky Drive
> Clarkdale, AZ 86324
> Ph. (928) 600-5459
> Fax (928) 649-3659
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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: ASTM A513 Tube Specs.

Mark,

A513 is mechanical tubing, hot rolled electric weld seam. It is a low carbon steel typically in the Fy 65 to 72 range and Fu 87. It is weldable, the welder just has to be qualified.

We typically treat it as FY 50 for a little extra factor on the material variability. There are many sizes available in the smaller sizes as an alternate to standard pipe.

Paul Feather PE, SE

pfeather@SE-Solutions.net

www.SE-Solutions.net

From: Mark Johnson [mailto:markajohn@yahoo.com]
Sent: Wednesday, August 06, 2008 2:37 PM
To: seaint@seaint.org
Subject: ASTM A513 Tube Specs.

Hello Folks,

One of my people wants to use A513 round tube for guardrails etc. Anyone know the Fy, Fu, weldability, etc. I didn't find it in the AISC manual or online quickly.

TIA
Mark Johnson

RE: Water Tanks

Conrad,

If I understand your question right, your plan is to rely on a steel
corrugated skirt to support the roof of a tank. There isn't enough info
here to know how big the loads are or the size of the tank. What about
wind loads and uplift on the roof? The best method for proving it might
be mock-up testing. Short of that I would recommend designing
independent supports for the roof.

Dave Gaines, P.E.

Structural Project Engineer
HDR ONE COMPANY | Many Solutions
251 S. Lake Ave, Suite 1000
Pasadena, CA 91101
T: 626.584.4960
F: 626.584.1750
email: david.gaines@hdrinc.com

-----Original Message-----
From: Conrad Harrison [mailto:sch.tectonic@bigpond.com]
Sent: Wednesday, August 06, 2008 9:27 PM
To: seaint@seaint.org
Subject: Water Tanks

Hello,

Can anyone recommend a reference for checking the buckling capacity of
corrugated cladding, loaded across the corrugations?

The application is the wall of a water tank. The tank comprises of a
polymer liner, with a steel corrugated wall around and roof over: the
steel work is mostly there to hide the liner. To satisfy the certifier
we need to demonstrate the wall can take the roof live load.

TIA

Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic@bigpond.com
Adelaide
South Australia

wind on stair tower

I have been asked to look at a free standing stair tower situated next to a parking garage. The tower will be enclosed by the parking structure on two sides and is about 30ft tall. It will be enclosed by a screening material (“Green Screen” I believe it is called). I may be able to take some of the wind loads into the parking structure, but I think at this time, the remainder will be resisted by 2 vertical HSS sections. I have some questions regarding the calculations for the wind loading. What do you think, would this be a building or non-building structure. If building, would it be enclosed, open, or partially enclosed? If non building, would it be a tower, trussed tower or whatever ? I’m sorry, it seems that I am asking about the entire setup for the calculations, and I guess I am in a way. It doesn’t seem as though it really fits any of the definitions in ASCE 7-05. Maybe some of you can explain a little. Any one done something like this in the past?

Thanks,

Joe Grill

Wednesday, August 6, 2008

Re: plywood diaphragm to light gage

There are wood panel sheathed, cold-formed steel framed, screw attached
diaphragm shear values in the 2004 AISI Lateral Design standard (AISI-Lateral)
referenced in Section 2210 of the 2006 IBC. See www.cfsei.org for cold-formed
steel publications and technical notes (one is on pins). Also, there are
manufacturers that offer pins to attached wood sheathing to CFS framing and have code reports (www.icc-es.org).

________________________________________
From: Joseph R. Grill [jrgrill@cableone.net]
Sent: Thursday, July 31, 2008 11:22 AM
To: seaint@seaint.org
Subject: plywood diaphragm to light gage

Several years ago I believe I ask a question of the list to see if there was any
diaphragm values for plywood screwed to light gage supports. If I remember
correctly, someone posted some ICBO testing (maybe ICC is newer) that contained
diaphragm values. It may have been shot pins, I just don't remember. I have
searched through my library, but since my office has moved a couple of times
since then I can't find that information (if it existed in the first place). If
anyone out there has that information, I would appreciate a copy or a link to
the information. I have a client that is considering a roof system that would
require this, if possible.

Thanks,
Joe Grill

Joseph R. Grill, PE
Verde Valley Engineering, PLLC
2220 Sky Drive
Clarkdale, AZ 86324
Ph. (928) 600-5459
Fax (928) 649-3659

Water Tanks

Hello,

Can anyone recommend a reference for checking the buckling capacity of
corrugated cladding, loaded across the corrugations?

The application is the wall of a water tank. The tank comprises of a polymer
liner, with a steel corrugated wall around and roof over: the steel work is
mostly there to hide the liner. To satisfy the certifier we need to
demonstrate the wall can take the roof live load.

TIA

Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic@bigpond.com
Adelaide
South Australia

Re: ASTM A513 Tube Specs.

Mark,

ASTM A513 has over a dozen different grades with Yield Stresses ranging from 23 to 100 ksi and Ultimate Strength ranging from 38 to 110 ksi. You will need to be a little more specific or call a fabricator/supplier to see what is the most common grade for your application.

Thomas Hunt, S.E.
Fluor

Mark Johnson <markajohn@yahoo.com>
08/06/2008 02:36 PM
Please respond to seaint

To	seaint@seaint.org
cc
Subject	ASTM A513 Tube Specs.

Hello Folks,

One of my people wants to use A513 round tube for guardrails etc. Anyone know the Fy, Fu, weldability, etc. I didn't find it in the AISC manual or online quickly.

TIA
Mark Johnson

------------------------------------------------------------ The information transmitted is intended only for the person  or entity to which it is addressed and may contain  proprietary, business-confidential and/or privileged material.   If you are not the intended recipient of this message you are  hereby notified that any use, review, retransmission, dissemination,  distribution, reproduction or any action taken in reliance upon  this message is prohibited. If you received this in error, please  contact the sender and delete the material from any computer.    Any views expressed in this message are those of the individual  sender and may not necessarily reflect the views of the company.   ------------------------------------------------------------

ASTM A513 Tube Specs.

Hello Folks,

One of my people wants to use A513 round tube for guardrails etc. Anyone know the Fy, Fu, weldability, etc. I didn't find it in the AISC manual or online quickly.

TIA
Mark Johnson

RE: hooked ABs and ABs with bearing plates

I believe that the ACI 349 anchor bolt embedment method used to require that the tensile area of the pullout cone be reduced by the area of any bearing plates provided at the head (not sure if the current provisions address this). As Harold noted, research showed that bearing plates could be detrimental because of reduced bond to the concrete below the bearing plate. Bearing plates were provided mainly to reduce bearing stresses at the head - but research has shown that a standard bolt head is adequate to develop the anchor in tension via bearing on concrete. This does create high bearing stresses which also have a lateral component, requiring adequate side cover.

As with others, I then stopped using bearing plates at embedded anchor bolts - also stopped using hooked anchor bolts, since headed bolts were found to perform better.

Bill Sherman

CH2M HILL / DEN

720-286-2792

From: Harold Sprague [mailto:spraguehope@hotmail.com]
Sent: Wednesday, August 06, 2008 8:37 AM
To: seaint@seaint.org
Subject: RE: hooked ABs

Suresh,
Most of the research I have seen is a mixed bag. Most of the research used hex heads.

I have a fundamental problem with increasing Abrg and that has to do with the required stiffness of the bearing plate. In order to be effective, the thickness gets huge. TVA performed some studies many years ago that fed into the ACI 349, and they found bearing plates to actually reduce the pull out strength.

Regards,
Harold Sprague

From: Suresh.Acharya@ci.concord.ca.us
To: seaint@seaint.org
Subject: RE: hooked ABs
Date: Tue, 5 Aug 2008 10:23:11 -0700

Harold & Andrew,

Are not the ACI Appendix D formulas specifically intended for standard welded headed anchors because the tests were done on these type of anchors? In the formulas, edge distances are measured from free edge to the center of bolts. Formulas give substantially greater pull-out and side-face blowout capacities if "Abrg" is increased (i.e. by using bigger washer plates), but the distance to the face of head/washer from free edge is never a variable in the formulas. Does that mean "Abrg" should be limited to the standard areas from PCI handbook in calculations, and the thickness of plates should match the standard thickness of heads?

Also, any oversized hole in the plate may affect the shear capacities.

Suresh Acharya, S.E.

From: Andrew Kester, PE [mailto:akester@cfl.rr.com]
Sent: Tuesday, August 05, 2008 8:26 AM
To: seaint@seaint.org
Subject: re: hooked ABs

I agree with Harold, I have never heard anything great about hooked ABs though they are still used all over the place. My boss stopped using them when I first started out of college about a decade ago because he read they "would fail by 'snaking' out of the house (wait, how did that much time just slip by!)...

Simpson in Jacksonville, FL (may have something sim. in TX or CA) has a one day seminar regarding their epoxies, bolts, etc. With audience participation, they drill holes in a big block of concrete and then after lunch you test them, even the epoxy anchors. Great demonstrations, as the epoxy would either shear cone fail the concrete or fail the rod in tension. The hooked L bolts always "snaked" out of the hole with the L straightening out.

If we have a connection at a foundation in particular, with any kind of uplift, we use all-thread rods with two nuts and a 2" SQ washer at the end. Nobody ever complains but if they do Simpson makes a PL1/4x2x2 I have seen at Home Depot. For really big uplift conditions at footings we will sometimes make those washers bigger or just use an embed plate that would have to fail in punching shear. We usually detail a couple of pieces of rebar sitting on top of the plate for a little feather in our cap.

HTH,

Andrew

Andrew Kester, P.E.
Principal/Project Manager
ADK Structural Engineering, PLLC
1510 E. Colonial Drive, Suite 301
Orlando, FL 32803

Get more from your digital life. Find out how.

RE: hooked ABs

Suresh,
Most of the research I have seen is a mixed bag. Most of the research used hex heads.

I have a fundamental problem with increasing Abrg and that has to do with the required stiffness of the bearing plate. In order to be effective, the thickness gets huge. TVA performed some studies many years ago that fed into the ACI 349, and they found bearing plates to actually reduce the pull out strength.

Regards,
Harold Sprague

From: Suresh.Acharya@ci.concord.ca.us
To: seaint@seaint.org
Subject: RE: hooked ABs
Date: Tue, 5 Aug 2008 10:23:11 -0700

Harold & Andrew,

Are not the ACI Appendix D formulas specifically intended for standard welded headed anchors because the tests were done on these type of anchors? In the formulas, edge distances are measured from free edge to the center of bolts. Formulas give substantially greater pull-out and side-face blowout capacities if "Abrg" is increased (i.e. by using bigger washer plates), but the distance to the face of head/washer from free edge is never a variable in the formulas. Does that mean "Abrg" should be limited to the standard areas from PCI handbook in calculations, and the thickness of plates should match the standard thickness of heads?

Also, any oversized hole in the plate may affect the shear capacities.

Suresh Acharya, S.E.

From: Andrew Kester, PE [mailto:akester@cfl.rr.com]
Sent: Tuesday, August 05, 2008 8:26 AM
To: seaint@seaint.org
Subject: re: hooked ABs

I agree with Harold, I have never heard anything great about hooked ABs though they are still used all over the place. My boss stopped using them when I first started out of college about a decade ago because he read they "would fail by 'snaking' out of the house (wait, how did that much time just slip by!)...

Simpson in Jacksonville, FL (may have something sim. in TX or CA) has a one day seminar regarding their epoxies, bolts, etc. With audience participation, they drill holes in a big block of concrete and then after lunch you test them, even the epoxy anchors. Great demonstrations, as the epoxy would either shear cone fail the concrete or fail the rod in tension. The hooked L bolts always "snaked" out of the hole with the L straightening out.

If we have a connection at a foundation in particular, with any kind of uplift, we use all-thread rods with two nuts and a 2" SQ washer at the end. Nobody ever complains but if they do Simpson makes a PL1/4x2x2 I have seen at Home Depot. For really big uplift conditions at footings we will sometimes make those washers bigger or just use an embed plate that would have to fail in punching shear. We usually detail a couple of pieces of rebar sitting on top of the plate for a little feather in our cap.

HTH,

Andrew

Andrew Kester, P.E.
Principal/Project Manager
ADK Structural Engineering, PLLC
1510 E. Colonial Drive, Suite 301
Orlando, FL 32803

Get more from your digital life. Find out how.

RE: Concrete additives for Pool on roof?

Stan speaks wisdom. You may want to consider developing a concrete mix design predicated on performance to include shrinkage and permeability. We also loose sight of what is done just to pump concrete. You can also restrict or preclude pumping concrete. With the mini-conveyors and the option of bucketing concrete, it is not that much of an encumbrance.

Regards,
Harold Sprague

From: sscholl2@juno.com
Date: Wed, 6 Aug 2008 04:43:50 +0000
To: seaint@seaint.org
Subject: Re: Concrete additives for Pool on roof?

Properly proportioned and mixed concrete is water tight. No admixtures are needed.
Do not use less than a 6 sack mix. In public works, for water reservoirs we use concrete without admixtures regularly.
Stan Scholl, PE
Laguna Beach, CA

____________________________________________________________
Click here to find the low cost way to send and receive faxes by email!

Get more from your digital life. Find out how.

RE: hooked ABs -- "buggered nuts" (another technical term :)

foul = buggered = mechanically deformed

Regards,
Harold Sprague

> From: t.w.allen@cox.net
> To: seaint@seaint.org
> Subject: RE: hooked ABs -- "buggered nuts" (another technical term :)
> Date: Tue, 5 Aug 2008 16:06:44 -0700
>
> foul = buggered
>
> Q.E.D.
>
> :o)
>
> T. William (Bill) Allen, S.E.
> ALLEN DESIGNS
> Consulting Structural Engineers
>
>
> > -----Original Message-----
> > From: Drew Morris [mailto:dmorris@bbfm.com]
> > Sent: Tuesday, August 05, 2008 10:45 AM
> > To: seaint@seaint.org
> > Subject: Re: hooked ABs -- "buggered nuts" (another technical term :)
>
> <snip>
>
> > Or foul the threads.
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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
> ******* ****** ****** ****** ******* ****** ****** ********

Get more from your digital life. Find out how.

Tuesday, August 5, 2008

Re: more aci 318

There is a simple way to get around the Appendix D shear cone failure limitation. Add shear stirrups or stud rails that pass through the failure cone. Then you design the transfer from the AB to the shear reinforcement using a strut and tie approach. This is discussed in ACI 318-08 Appendix D.
If you were near the edge of concrete you might still have a side blow out issue.
When you have multiple bolts in a group placing a large plate in the concrete can actually reduce your capacity. There is a good graphic in ICC AC308 which explains why. You want to engage the concrete below the bolt group.
According to Appendix D a standard double hex bolt will develop most anchor rods. With the high strength rods you might need a plate but I would keep it thick. If the flexural flexibility of the plate is significant it will not act as you assumed.
Mark Gilligan

Re: Concrete additives for Pool on roof?

Properly proportioned and mixed concrete is water tight. No admixtures are needed.

Do not use less than a 6 sack mix. In public works, for water reservoirs we use concrete without admixtures regularly.

Stan Scholl, PE

Laguna Beach, CA

RE: hooked ABs -- "buggered nuts" (another technical term :)

You still have friends that blush?

=8^O

I’m most of all surprised at your European experiences. I thought Europeans were “all accepting”, etc.

I guess not.

Sigh…

T. William (Bill) Allen, S.E.

ALLEN DESIGNS

Consulting Structural Engineers
V (949) 248-8588 • F(949) 209-2509

-----Original Message-----
From: Rhkratzse@aol.com [mailto:Rhkratzse@aol.com]
Sent: Tuesday, August 05, 2008 6:14 PM
To: jeffsmith7@comcast.net; seaint@seaint.org
Subject: Re: hooked ABs -- "buggered nuts" (another technical term :)

I don't think it's a waste of bandwidth, especially since BW can be reused and recycled. :)

I understand that "buggered" is somewhat off-color in some parts of the world. Similarly I used the universal "time out" signal recently and a friend from Europe blushed and informed me that it's a *really* rude gesture and not to do it, at least not in the Czech Republic, and certainly not to someone of the female persuasion. Who knew?

Similarly, I was in Europe wearing a "Roots" (brand of hippie shoes) T-shirt long ago and someone informed me that such shouldn't be worn in polite company.

Talk about a waste of BW!

Ralph

In a message dated 8/5/08 4:44:24 PM, jeffsmith7@comcast.net writes:

I googled buggered:
"A BBC survey in 2000 rated bugger as 21st in the list of worst swearwords,
above Jesus Christ (25) and God (28). 21% of people surveyed thought it was
not swearing and 47% considered it mild swearing." Pardon the waste of
bandwidth.

-----Original Message-----
From: Bill Allen [mailto:t.w.allen@cox.net]
Sent: Tuesday, August 05, 2008 4:07 PM
To: seaint@seaint.org
Subject: RE: hooked ABs -- "buggered nuts" (another technical term :)

foul = buggered

Q.E.D.

:o)

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

> -----Original Message-----
> From: Drew Morris [mailto:dmorris@bbfm.com]
> Sent: Tuesday, August 05, 2008 10:45 AM
> To: seaint@seaint.org
> Subject: Re: hooked ABs -- "buggered nuts" (another technical term :)

<snip>

> Or foul the threads.

**************
Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos.
(http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 )

Re: hooked ABs -- "buggered nuts" (another technical term :)

On Aug 5, 2008, at 8:13 PM, Rhkratzse@aol.com wrote:

> understand that "buggered" is somewhat off-color in some parts of
> the world. Similarly I used the universal "time out" signal
> recently and a friend from Europe blushed and informed me that it's
> a *really* rude gesture and not to do it, at least not in the Czech
> Republic, and certainly not to someone of the female persuasion.
> Who knew?
It started out as a reference to sodomy originally in connection with
heretical religious practices. It was a capital crime in the Royal
Navy, according to Article 29 of the Articles of War. Probably not a
term you'd want to use unadvisedly.

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/

Re: hooked ABs -- "buggered nuts" (another technical term :)

I googled buggered:
"A BBC survey in 2000 rated bugger as 21st in the list of worst swearwords,
above Jesus Christ (25) and God (28). 21% of people surveyed thought it was
not swearing and 47% considered it mild swearing." Pardon the waste of
bandwidth.

-----Original Message-----
From: Bill Allen [mailto:t.w.allen@cox.net]
Sent: Tuesday, August 05, 2008 4:07 PM
To: seaint@seaint.org
Subject: RE: hooked ABs -- "buggered nuts" (another technical term :)

foul = buggered

Q.E.D.

:o)

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

> -----Original Message-----
> From: Drew Morris [mailto:dmorris@bbfm.com]
> Sent: Tuesday, August 05, 2008 10:45 AM
> To: seaint@seaint.org
> Subject: Re: hooked ABs -- "buggered nuts" (another technical term :)

<snip>

> Or foul the threads.

**************
Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos.
(http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 )