Structural Engineering: 2008-08-31

Saturday, September 6, 2008

RE: Galvanized bolts req'd in PT wood?

Correct me if I am wrong, but if you specify Ilevel Strandguard treated sill plates you do not need to use galvanized fasteners or barriers, since their zinc borate does not increase corrosivity.

I have been specifying HDG anchors, washers and plywood sill plate nails at CCA pressure treated sill plates and any thing else that comes into contact. I specify a barrier between holdowns and the treated plate, such as polyken tape or Grace Vycor. See http://www.strongtie.com/ftp/bulletins/T-PTBARRIER08.pdf

Jeff

From: bart@nbse.com [mailto:bart@nbse.com]
Sent: Saturday, September 06, 2008 6:01 PM
To: seaint@seaint.org
Subject: Re: Galvanized bolts req'd in PT wood?

Diane,

I share your interpretation as well and do not think it applies to anchor bolts as pressure treatment does not usually occur through the entire thickness of the plate.

(not to mention the holes are larger than the bolt...technically not in direct contact) However.....when the building dept./and/or inpsectors are adamant, I have told the contractor to wipe the bolts with solvent and paint....it usuallly has done the trick...

bart

----- Original Message -----
From: "Gould, Diane"
To: seaint@seaint.org
Subject: Galvanized bolts req'd in PT wood?
Date: Thu, 4 Sep 2008 15:29:19 -0700

2007 CBC/2006 IBC Section 2304.9.5 states that “fasteners” for PT & fire-retardant wood shall be galvanized, stainless, silicon bronze, or copper. 2001 CBC/2000 UBC Section 2304.3 also stipulated this requirement. On a wood-frame job currently in construction, we have pressure-treated sill plates and the inspector is saying that galvanized anchor bolts (sill bolts and hold-down bolts) are a “code requirement”.

I understand the new preservatives can be much more corrosive than the old stuff, but was of the impression that bolts are of a large-enough diameter to not pose a concern. I had thought I read that somewhere but I cannot find any published code language, commentary, or interpretations to support this position. Also, I started thinking, what about the washer? Is that a “fastener”? It’s in contact with the PT wood - does that mean it needs to be galvanized too? I could not find a definition of “fastener” in the CBC/IBC.

I’ve been away from wood design for awhile and am feeling a little rusty, so I’m hoping someone can give me some guidance on this.

Thanks in advance,

Diane C. Gould, S.E.

Senior Structural Engineer

DGS-RESD-PSB

Design Services Section

707 Third Street, Suite 4-105

West Sacramento, CA 95605

(916) 375-4219 phone

(916) 375-4916 fax

diane.gould@dgs.ca.gov

BUILDING GREEN • BUYING GREEN • WORKING GREEN

<< image001.jpg >>

Bart Needham, SE Principal, nbse associates, inc. civil & structural engineers Office 206-780-6822 Office 805-452-8152 Fax    206-780-6683 Fax    208-693-3667 Mobile 206-300-2346  Office locations: 629 State Street #230 Santa Barbara, CA  93101  205 Fairview Lane Suite 100 Paso Robles, CA  93446  365 Ericksen Ave. NE Suite 328 Bainbridge Island, WA  98110  Mail and Deliveries: 321 High School Rd. NE Suite D-3 PMB 216 Bainbridge Island, WA  98110

Re: Galvanized bolts req'd in PT wood?

Diane,

I share your interpretation as well and do not think it applies to anchor bolts as pressure treatment does not usually occur through the entire thickness of the plate.

bart

----- Original Message -----
From: "Gould, Diane"
To: seaint@seaint.org
Subject: Galvanized bolts req'd in PT wood?
Date: Thu, 4 Sep 2008 15:29:19 -0700

2007 CBC/2006 IBC Section 2304.9.5 states that "fasteners" for PT & fire-retardant wood shall be galvanized, stainless, silicon bronze, or copper. 2001 CBC/2000 UBC Section 2304.3 also stipulated this requirement. On a wood-frame job currently in construction, we have pressure-treated sill plates and the inspector is saying that galvanized anchor bolts (sill bolts and hold-down bolts) are a "code requirement".

I understand the new preservatives can be much more corrosive than the old stuff, but was of the impression that bolts are of a large-enough diameter to not pose a concern. I had thought I read that somewhere but I cannot find any published code language, commentary, or interpretations to support this position. Also, I started thinking, what about the washer? Is that a "fastener"? It's in contact with the PT wood - does that mean it needs to be galvanized too? I could not find a definition of "fastener" in the CBC/IBC.

I've been away from wood design for awhile and am feeling a little rusty, so I'm hoping someone can give me some guidance on this.

Thanks in advance,

Diane C. Gould, S.E.

Senior Structural Engineer

DGS-RESD-PSB

Design Services Section

707 Third Street, Suite 4-105

West Sacramento, CA 95605

(916) 375-4219 phone

(916) 375-4916 fax

diane.gould@dgs.ca.gov

BUILDING GREEN • BUYING GREEN • WORKING GREEN

<< image001.jpg >>

Bart Needham, SE Principal, nbse associates, inc. civil & structural engineers Office 206-780-6822 Office 805-452-8152 Fax    206-780-6683 Fax    208-693-3667 Mobile 206-300-2346  Office locations: 629 State Street #230 Santa Barbara, CA  93101  205 Fairview Lane Suite 100 Paso Robles, CA  93446  365 Ericksen Ave. NE Suite 328 Bainbridge Island, WA  98110  Mail and Deliveries: 321 High School Rd. NE Suite D-3 PMB 216 Bainbridge Island, WA  98110

Re: e-mail

Thanks Phani.

Ray Shreenan

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

From: Phani Krishna

To: seaint@seaint.org

Sent: Friday, September 05, 2008 8:59 PM

Subject: RE: e-mail

I 'm also getting them....!!!

Regards,
Phani Krishna,
Sr.Design Engineer,
Larsen&Toubro(L&T),
GES.

From: Thor Tandy [vicpeng@telus.net]
Sent: Saturday, September 06, 2008 5:59 AM
To: seaint@seaint.org
Subject: RE: e-mail

I've been getting them ...

Thor A. Tandy P.Eng, C.Eng, Struct.Eng, MIStructE
Victoria, BC
Canada

-----Original Message-----
From: raymond shreenan [mailto:rshreenan@roadrunner.com]
Sent: Friday, September 05, 2008 4:57 PM
To: seaint@seaint.org
Subject: e-mail

Is the web site still up? I haven't been receiving any messages.

Ray Shreenan

"This Message and its contents is intended solely for the addressee and is proprietary.Information in this mail is for L&T Business Usage only. Any Use to other than the addressee is misuse and infringement to Proprietorship of L&T ECC.If you are not the addressee please return the mail to the sender.L&T ECC DIVISION"

Friday, September 5, 2008

RE: e-mail

I 'm also getting them....!!!

Regards,
Phani Krishna,
Sr.Design Engineer,

Larsen&Toubro(L&T),
GES.

From: Thor Tandy [vicpeng@telus.net]
Sent: Saturday, September 06, 2008 5:59 AM
To: seaint@seaint.org
Subject: RE: e-mail

I've been getting them ...

Thor A. Tandy P.Eng, C.Eng, Struct.Eng, MIStructE
Victoria, BC
Canada

-----Original Message-----
From: raymond shreenan [mailto:rshreenan@roadrunner.com]
Sent: Friday, September 05, 2008 4:57 PM
To: seaint@seaint.org
Subject: e-mail

Is the web site still up? I haven't been receiving any messages.

Ray Shreenan

"This Message and its contents is intended solely for the addressee and is proprietary.Information in this mail is for L&T Business Usage only. Any Use to other than the addressee is misuse and infringement to Proprietorship of L&T ECC.If you are not the addressee please return the mail to the sender.L&T ECC DIVISION"

Re: Structural Logs

Tom, sure there are many factors involved, but at least from the point of view of cut fibres, the log is stronger than sawn lumber of the same sectional area. This claim comes by way of Forintek (FPInnovations), a forest products reaearch organisation in Canada. I didn't question it, because it seems logical to me.

On Fri, Sep 5, 2008 at 10:01 AM, Tom Skaggs <tom.skaggs@apawood.org> wrote:

Please provide a credible reference to back up your below claim. I've never heard this claim, and am quite skeptical that this is true. There are many factors that affect strength of wood/timber, including knots, direction of grain, density et cetera.

Tom

Thomas D. Skaggs, Ph.D., P.E.

Manager, Product Evaluation

APA

7011 S. 19th Street

Tacoma, WA 98466

253-620-7479 (office)

253-620-7235 (fax)

tom.skaggs@apawood.org

www.apawood.org

From: Kevin Below [mailto:kbofoz@gmail.com]
Sent: Thursday, September 04, 2008 17:12
To: seaint@seaint.org
Subject: Re: Structural Logs

Actually, logs are stronger than the equivalent sawn lumber of the same area, because none of the fibres is cut - they are all continuous.

On Thu, Aug 28, 2008 at 11:51 AM, Chris Slater <chris@jdwylieengineering.com> wrote:

Thanks very much Gary.

On Thu, Aug 28, 2008 at 8:11 AM, Ehrlich, Gary <gehrlich@nahb.com> wrote:
> Chris,
>
> The ICC-400 Standard on the Design and Construction of Log Structures
> (link:
> http://www.iccsafe.org/e/prodshow.html?prodid=7017S06&stateInfo=btjPdpGjFrbfslkl1466|5) is probably be a good start. I believe it does have

> section properties for log members.
>
> Regards,
> Gary
>
> Gary J. Ehrlich, PE
> Program Manager, Structural Codes & Standards
> National Association of Home Builders (NAHB)
> 1201 15th Street, NW, Washington, DC 20005
> ph: 202-266-8545 or 800-368-5242 x8545
> fax: 202-266-8369
> gehrlich@nahb.com
>
> Attend the 2009 International Builders' Show
> January 20-23, 2009, Las Vegas, NV
> www.BuildersShow.com
> -----Original Message-----
> From: chris.slater@gmail.com [mailto:chris.slater@gmail.com] On Behalf
> Of Chris Slater
> Sent: Thursday, August 28, 2008 10:54 AM
> To: seaint@seaint.org
> Subject: Structural Logs
>
> Hi All,
>
> We have had a couple of projects come up where the homeowner wants
> ridge beams, patio roof rafters and structural posts to be made of
> logs. Our initial thought was just to conservatively design for a
> nominal member that fits in a square inside the cross section of the
> log. Does anyone have experience and/or resources for designing and
> detailing this type of construction?
>
> Thanks very much,
>
> Chris Slater
>
> ******* ****** ******* ******** ******* ******* ******* ***
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******* ****** ******* ******** ******* ******* ******* ***
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*
* This email was sent to you via Structural Engineers
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Re: e-mail

Thanks Thor.

Ray Shreenan

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

From: Thor Tandy

To: seaint@seaint.org

Sent: Friday, September 05, 2008 5:29 PM

Subject: RE: e-mail

I've been getting them ...

Thor A. Tandy P.Eng, C.Eng, Struct.Eng, MIStructE
Victoria, BC
Canada

-----Original Message-----
From: raymond shreenan [mailto:rshreenan@roadrunner.com]
Sent: Friday, September 05, 2008 4:57 PM
To: seaint@seaint.org
Subject: e-mail

Is the web site still up? I haven't been receiving any messages.

Ray Shreenan

RE: e-mail

I've been getting them ...

Thor A. Tandy P.Eng, C.Eng, Struct.Eng, MIStructE
Victoria, BC
Canada

-----Original Message-----
From: raymond shreenan [mailto:rshreenan@roadrunner.com]
Sent: Friday, September 05, 2008 4:57 PM
To: seaint@seaint.org
Subject: e-mail

Is the web site still up? I haven't been receiving any messages.

Ray Shreenan

e-mail

Is the web site still up? I haven't been receiving any messages.

Ray Shreenan

RE: Calgary, Alberta

Thanks Daryl,

The clients current needs revolve around the inspection end of the business rather than implementing a new system.

If either Curtis or Wayne is interested please let me know and I will establish contact with the client.

Paul Feather PE, SE

pfeather@SE-Solutions.net

www.SE-Solutions.net

From: Daryl Richardson [mailto:h.d.richardson@shaw.ca]
Sent: Thursday, September 04, 2008 11:08 AM
To: seaint@seaint.org
Cc: Curtis Feeg; Wayne Kassian
Subject: Re: Calgary, Alberta

Paul,

         As a semi-retired individual I am not interested in seeking out more work at the present time; but I do know two others that you can contact. Both are well qualified and I'm sure you would be satisfied with either.

        Curtis Feeg, like myself, is a sole practitioner with many years of experience in a broad range of structural projects.

        Wayne Kassian is a principal in a larger firm, Kassian Dyck Associates who have a website at www.kdassociates.com. I have not been in close contact with this company for a while; but I believe they have four or five capable engineers (or more) plus support staff.

        There are, of course many others; but these are the two at the top of my list. Good luck with your projects.

Regards,

H. Daryl Richardson

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

From: Paul Feather

To: seaint@seaint.org

Sent: Thursday, September 04, 2008 11:47 AM

Subject: Calgary, Alberta

I need a professional engineer in Calgary.

Small contract, but great contact.

The client is Citadel / Lerch Bates, the premier window washing and equipment consultant in the world. I believe they have 6 of the worlds top ten tallest buildings as systems they designed and implemented, including that new monster tower in Dubai.

Anyone available?

Paul Feather PE, SE

pfeather@SE-Solutions.net

www.SE-Solutions.net

RE: Structural Logs

Please provide a credible reference to back up your below claim. I’ve never heard this claim, and am quite skeptical that this is true. There are many factors that affect strength of wood/timber, including knots, direction of grain, density et cetera.

Tom

Thomas D. Skaggs, Ph.D., P.E.

Manager, Product Evaluation

APA

7011 S. 19th Street

Tacoma, WA 98466

253-620-7479 (office)

253-620-7235 (fax)

tom.skaggs@apawood.org

www.apawood.org

From: Kevin Below [mailto:kbofoz@gmail.com]
Sent: Thursday, September 04, 2008 17:12
To: seaint@seaint.org
Subject: Re: Structural Logs

Actually, logs are stronger than the equivalent sawn lumber of the same area, because none of the fibres is cut - they are all continuous.

On Thu, Aug 28, 2008 at 11:51 AM, Chris Slater <chris@jdwylieengineering.com> wrote:

Thanks very much Gary.

On Thu, Aug 28, 2008 at 8:11 AM, Ehrlich, Gary <gehrlich@nahb.com> wrote:
> Chris,
>
> The ICC-400 Standard on the Design and Construction of Log Structures
> (link:
> http://www.iccsafe.org/e/prodshow.html?prodid=7017S06&stateInfo=btjPdpGjFrbfslkl1466|5) is probably be a good start. I believe it does have
> section properties for log members.
>
> Regards,
> Gary
>
> Gary J. Ehrlich, PE
> Program Manager, Structural Codes & Standards
> National Association of Home Builders (NAHB)
> 1201 15th Street, NW, Washington, DC 20005
> ph: 202-266-8545 or 800-368-5242 x8545
> fax: 202-266-8369
> gehrlich@nahb.com
>
> Attend the 2009 International Builders' Show
> January 20-23, 2009, Las Vegas, NV
> www.BuildersShow.com
> -----Original Message-----
> From: chris.slater@gmail.com [mailto:chris.slater@gmail.com] On Behalf
> Of Chris Slater
> Sent: Thursday, August 28, 2008 10:54 AM
> To: seaint@seaint.org
> Subject: Structural Logs
>
> Hi All,
>
> We have had a couple of projects come up where the homeowner wants
> ridge beams, patio roof rafters and structural posts to be made of
> logs. Our initial thought was just to conservatively design for a
> nominal member that fits in a square inside the cross section of the
> log. Does anyone have experience and/or resources for designing and
> detailing this type of construction?
>
> Thanks very much,
>
> Chris Slater
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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
> ******* ****** ****** ****** ******* ****** ****** ********
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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
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> *
> * 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
> ******* ****** ****** ****** ******* ****** ****** ********
>

******* ****** ******* ******** ******* ******* ******* ***
* 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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* without your permission. Make sure you visit our web
* site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********

Thursday, September 4, 2008

Re: Structural Logs

Actually, logs are stronger than the equivalent sawn lumber of the same area, because none of the fibres is cut - they are all continuous.

On Thu, Aug 28, 2008 at 11:51 AM, Chris Slater <chris@jdwylieengineering.com> wrote:

Thanks very much Gary.

On Thu, Aug 28, 2008 at 8:11 AM, Ehrlich, Gary <gehrlich@nahb.com> wrote:
> Chris,
>
> The ICC-400 Standard on the Design and Construction of Log Structures
> (link:
> http://www.iccsafe.org/e/prodshow.html?prodid=7017S06&stateInfo=btjPdpGj
> Frbfslkl1466|5) is probably be a good start. I believe it does have
> section properties for log members.
>
> Regards,
> Gary
>
> Gary J. Ehrlich, PE
> Program Manager, Structural Codes & Standards
> National Association of Home Builders (NAHB)
> 1201 15th Street, NW, Washington, DC 20005
> ph: 202-266-8545 or 800-368-5242 x8545
> fax: 202-266-8369
> gehrlich@nahb.com
>
> Attend the 2009 International Builders' Show
> January 20-23, 2009, Las Vegas, NV
> www.BuildersShow.com
> -----Original Message-----
> From: chris.slater@gmail.com [mailto:chris.slater@gmail.com] On Behalf
> Of Chris Slater
> Sent: Thursday, August 28, 2008 10:54 AM
> To: seaint@seaint.org
> Subject: Structural Logs
>
> Hi All,
>
> We have had a couple of projects come up where the homeowner wants
> ridge beams, patio roof rafters and structural posts to be made of
> logs. Our initial thought was just to conservatively design for a
> nominal member that fits in a square inside the cross section of the
> log. Does anyone have experience and/or resources for designing and
> detailing this type of construction?
>
> Thanks very much,
>
> Chris Slater
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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
> ******* ****** ****** ****** ******* ****** ****** ********
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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
> ******* ****** ****** ****** ******* ****** ****** ********
>

******* ****** ******* ******** ******* ******* ******* ***
* 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: Minimum Slab Reinforcing

I agree with you, Gil. There are certainly areas of a suspended slab where there is no top steel - the intersecting middle strips.

On Thu, Sep 4, 2008 at 7:30 PM, Gil Brock <gil@raptsoftware.com> wrote:

There are 2 reasons for minimum reinforcement

Shrinkage and Temperature - This requirement is satisfied by ensuring that the total reinforcement in the 2 faces is covered by 10..7.4 (7.12). This requirement is normally applied where there is no significant flexural action and if in cases where the slab would not fail if this reinforcement were to fail, in other words if a load path still exists without this reinforcement,. eg transverse reinforcement in a one way slab. ACI318 does suggest that this requirement also applies in raft slabs but I cannot understand why as there is significant flexural stress. Just because it is on the ground does not mean that failure of the reinforcement is not critical so, personally, I would ignore this as a code slip up.

Strength/Brittle failure - This requirement is satisfied by 10.5.1 etc and requires a minimum area of reinforcement at each face of the concrete in tension. The reason given in the commentary is that the cracked strength must be greater than the uncracked strength, and there is good reason for this as it explains. The other forgotten reason is that we never check the strain level in reinforcement at ultimate strength. The smaller the area of reinforcement , the higher the strain in the reinforcement at the tension face The minimum reinforcement rule is also meant to limit this strain in the reinforcement to avoid snapping of the reinforcement which is a brittle and possibly catastrophic failure. So, where there is significant flexure and the load path for the slab requires strength at a cross-section, minimum reinforcement is required at an section where there is tension at a concrete face. This does not necessarily require reinforcement at both faces everywhere as someone suggested, only at locations where there is flexural tension.

So, in conclusion, if you are relying on reinforcement to provide flexural strength and to support the structure, the minimum is required on any face that requires tension reinforcement.

At 07:01 AM 5/09/2008, you wrote:

As Bill noted, to my knowledge, the intent of the provision is to provide the TOTAL amount of shrinkage and temperature steel in the cross section that you must provide. The code then leaves it up to you to decide how to distribute that steel with in the cross section, with the only limitations being on bar spacing in the "out of plane" direction...although you could also use those spacing limitations in the other direction for layers of bars if you have a slab of sufficient thickness (i.e. greater than 18 inches).

Regards,

Scott
Adrian, MI

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

From: William.Sherman@CH2M.com [ mailto:William.Sherman@CH2M.com]

Sent: Thursday, September 04, 2008 3:36 PM

To: seaint@seaint.org

Subject: RE: Minimum Slab Reinforcing

The code does not refer to "each face", just to "area of shrinkage and temperature reinforcement" based on gross area of concrete. The "common" practice is to provide half of this area in each face as a minimum (except for thin slabs with one mat of steel). But the code doesn't say it has to be done this way - if the combined effect of the top and bottom steel areas meets the code minimum for S&T steel, then the code has been met. (You still have to provide tension steel in any face that has design tension.)

Bill Sherman

CH2M HILL / DEN

720-286-2792

From: William Haynes [ mailto:gtg740p@gmail.com]

Sent: Thursday, September 04, 2008 1:15 PM

To: seaint@seaint.org

Subject: Re: Minimum Slab Reinforcing

If there is tension at the top and bottom, then you need to provide 0.0018*Ag at EACH face.

Will H.

On Thu, Sep 4, 2008 at 3:06 PM, David Topete <d.topete73@gmail.com> wrote:

I've always checked the 0.0018*Ag for top and bottom min steel. i.e., if i have a 24" thick footing (mat or grade beam), I'll check As,min top = 0.0018 * 12" * 24"/2 = 0.259 sq.in./ft. Use #4 @ 9"o.c., or something like that...

On Thu, Sep 4, 2008 at 11:28 AM, Josh Plummer <joshp@risatech.com> wrote:

In ACI 318, section 10.5.4, the code states that the minimum flexural reinforcement for slabs and footings should be the same as given in 7.12 (which is the temperature / shrinkage requirements).

I've interpreted this to me that regardless of what the area of steel required by analysis is, you can never let your total slab reinforcing (As_top + As_bottom) be less than the minimum amount required for temperature and shrinkage.

Now, I've got another engineer who is arguing that the Asmin = 0.0018 * Agross requirement applies for BOTH the top steel reinforcing and the bottom steel reinforcing. Since temperature and shrinkage controls the design of most relatively thick mat foundations, this interpretation would effectively double the amount of steel required in these mats.

Any opinions? Has anyone heard of someone interpreting this section of code in this manner? Is it common?

Sincerely,

Josh Plummer, SE

--

David Topete, SE

Regards Gil Brock
Prestressed Concrete Design Consultants Pty. Ltd. (ABN 84 003 163 586)
5 Cameron Street Beenleigh Qld 4207 Australia
Ph +61 7 3807 8022               Fax +61 7 3807 8422
email:            gil@raptsoftware.com
email:            sales@raptsoftware.com
email:            support@raptsoftware.com
webpage:         http://www.raptsoftware.com

RE: Minimum Slab Reinforcing

There are 2 reasons for minimum reinforcement

Shrinkage and Temperature - This requirement is satisfied by ensuring that the total reinforcement in the 2 faces is covered by 10..7.4 (7.12). This requirement is normally applied where there is no significant flexural action and if in cases where the slab would not fail if this reinforcement were to fail, in other words if a load path still exists without this reinforcement,. eg transverse reinforcement in a one way slab. ACI318 does suggest that this requirement also applies in raft slabs but I cannot understand why as there is significant flexural stress. Just because it is on the ground does not mean that failure of the reinforcement is not critical so, personally, I would ignore this as a code slip up.

Strength/Brittle failure - This requirement is satisfied by 10.5.1 etc and requires a minimum area of reinforcement at each face of the concrete in tension. The reason given in the commentary is that the cracked strength must be greater than the uncracked strength, and there is good reason for this as it explains. The other forgotten reason is that we never check the strain level in reinforcement at ultimate strength. The smaller the area of reinforcement , the higher the strain in the reinforcement at the tension face The minimum reinforcement rule is also meant to limit this strain in the reinforcement to avoid snapping of the reinforcement which is a brittle and possibly catastrophic failure. So, where there is significant flexure and the load path for the slab requires strength at a cross-section, minimum reinforcement is required at an section where there is tension at a concrete face. This does not necessarily require reinforcement at both faces everywhere as someone suggested, only at locations where there is flexural tension.

So, in conclusion, if you are relying on reinforcement to provide flexural strength and to support the structure, the minimum is required on any face that requires tension reinforcement.

At 07:01 AM 5/09/2008, you wrote:

As Bill noted, to my knowledge, the intent of the provision is to provide the TOTAL amount of shrinkage and temperature steel in the cross section that you must provide. The code then leaves it up to you to decide how to distribute that steel with in the cross section, with the only limitations being on bar spacing in the "out of plane" direction...although you could also use those spacing limitations in the other direction for layers of bars if you have a slab of sufficient thickness (i.e. greater than 18 inches).

Regards,

Scott
Adrian, MI

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

From: William.Sherman@CH2M.com [ mailto:William.Sherman@CH2M.com]

Sent: Thursday, September 04, 2008 3:36 PM

To: seaint@seaint.org

Subject: RE: Minimum Slab Reinforcing

The code does not refer to "each face", just to "area of shrinkage and temperature reinforcement" based on gross area of concrete. The "common" practice is to provide half of this area in each face as a minimum (except for thin slabs with one mat of steel). But the code doesn't say it has to be done this way - if the combined effect of the top and bottom steel areas meets the code minimum for S&T steel, then the code has been met. (You still have to provide tension steel in any face that has design tension.)

Bill Sherman

CH2M HILL / DEN

720-286-2792

From: William Haynes [ mailto:gtg740p@gmail.com]

Sent: Thursday, September 04, 2008 1:15 PM

To: seaint@seaint.org

Subject: Re: Minimum Slab Reinforcing

If there is tension at the top and bottom, then you need to provide 0.0018*Ag at EACH face.

Will H.

On Thu, Sep 4, 2008 at 3:06 PM, David Topete <d.topete73@gmail.com> wrote:

I've always checked the 0.0018*Ag for top and bottom min steel. i.e., if i have a 24" thick footing (mat or grade beam), I'll check As,min top = 0.0018 * 12" * 24"/2 = 0.259 sq.in./ft. Use #4 @ 9"o.c., or something like that...

On Thu, Sep 4, 2008 at 11:28 AM, Josh Plummer <joshp@risatech.com> wrote:

In ACI 318, section 10.5.4, the code states that the minimum flexural reinforcement for slabs and footings should be the same as given in 7.12 (which is the temperature / shrinkage requirements).

I've interpreted this to me that regardless of what the area of steel required by analysis is, you can never let your total slab reinforcing (As_top + As_bottom) be less than the minimum amount required for temperature and shrinkage.

Now, I've got another engineer who is arguing that the Asmin = 0.0018 * Agross requirement applies for BOTH the top steel reinforcing and the bottom steel reinforcing. Since temperature and shrinkage controls the design of most relatively thick mat foundations, this interpretation would effectively double the amount of steel required in these mats.

Any opinions? Has anyone heard of someone interpreting this section of code in this manner? Is it common?

Sincerely,

Josh Plummer, SE

--

David Topete, SE

Regards Gil Brock
Prestressed Concrete Design Consultants Pty. Ltd. (ABN 84 003 163 586)
5 Cameron Street Beenleigh Qld 4207 Australia
Ph +61 7 3807 8022               Fax +61 7 3807 8422
email:            gil@raptsoftware.com
email:            sales@raptsoftware.com
email:            support@raptsoftware.com
webpage:         http://www.raptsoftware.com

Galvanized bolts req'd in PT wood?

2007 CBC/2006 IBC Section 2304.9.5 states that “fasteners” for PT & fire-retardant wood shall be galvanized, stainless, silicon bronze, or copper. 2001 CBC/2000 UBC Section 2304.3 also stipulated this requirement. On a wood-frame job currently in construction, we have pressure-treated sill plates and the inspector is saying that galvanized anchor bolts (sill bolts and hold-down bolts) are a “code requirement”.

I understand the new preservatives can be much more corrosive than the old stuff, but was of the impression that bolts are of a large-enough diameter to not pose a concern. I had thought I read that somewhere but I cannot find any published code language, commentary, or interpretations to support this position. Also, I started thinking, what about the washer? Is that a “fastener”? It’s in contact with the PT wood - does that mean it needs to be galvanized too? I could not find a definition of “fastener” in the CBC/IBC.

I’ve been away from wood design for awhile and am feeling a little rusty, so I’m hoping someone can give me some guidance on this.

Thanks in advance,

Diane C. Gould, S.E.

Senior Structural Engineer

DGS-RESD-PSB

Design Services Section

707 Third Street, Suite 4-105

West Sacramento, CA 95605

(916) 375-4219 phone

(916) 375-4916 fax

diane.gould@dgs.ca.gov

BUILDING GREEN • BUYING GREEN • WORKING GREEN

RE: Rock Veneer Support on timber

Take a look at Chapter 6 (Veneer) in the 2005 Masonry Code (aka ACI 530).
It has some provisions for vertical support of masonry veneer.

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill@cableone.net]
Sent: Thursday, September 04, 2008 11:15 AM
To: seaint@seaint.org
Subject: RE: Rock Veneer Support on timber

Thanks to David, David and Buddy,
I will look into the link from Buddy. I didn't think there was any more
restrictions, however you never know with this code where some little
paragraph can be hidden. Joe

-----Original Message-----
From: Showalter, Buddy [mailto:Buddy_Showalter@afandpa.org] On Behalf Of AWC
Info
Sent: Thursday, September 04, 2008 5:57 AM
To: seaint@seaint.org
Subject: Rock Veneer Support on timber

No other restrictions of which I am aware. However, there's some additional
information on deflection criteria for stud walls backing veneers in a
recent Structure Magazine article by the list's own Harold
Sprague:

http://www.structuremag.org/article.aspx?articleID=671

btw, this article resulted from a discussion on this listserver that Harold
so eloquently answered that we turned it into an article.

HTH

Buddy

John "Buddy" Showalter, P.E.
Director, Technical Media
AF&PA/American Wood Council
1111 19th Street, NW, Suite 800
Washington, DC 20036
P: 202-463-2769
F: 202-463-2791
http://www.awc.org
The American Wood Council (AWC) is the wood products division of the
American Forest & Paper Association (AF&PA). AWC develops internationally
recognized standards for wood design and construction. Its efforts with
building codes and standards, engineering and research, and technology
transfer ensure proper application for engineered and traditional wood
products.
*********************
The guidance provided herein is not a formal interpretation of any AF&PA
standard. Interpretations of AF&PA standards are only available through a
formal process outlined in AF&PA's standards development procedures.
*********************

From: "Joseph R. Grill" <jrgrill@cableone.net>
To: <seaint@seaint.org>
Subject: Rock Veneer Support on timber

I have a situation where I have an exterior stud wall that is covered with
rock veneer. The wall has a low parapet, just a couple of feet above the
roof, where the veneer will also be located on the interior face of the
parapet. I can't find anything in the IBC that would tell me I can't support
the small height of rock veneer, on the interior of the parapet, by a ledger
of some sort, which will be attached to the stud wall. 2304.12 tells me that
I have to check the wood members for long term deflection. Is there any
restrictions that I haven't found? Thanks, Joe Grill

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RE: Minimum Slab Reinforcing

As Bill noted, to my knowledge, the intent of the provision is to provide the TOTAL amount of shrinkage and temperature steel in the cross section that you must provide. The code then leaves it up to you to decide how to distribute that steel with in the cross section, with the only limitations being on bar spacing in the "out of plane" direction...although you could also use those spacing limitations in the other direction for layers of bars if you have a slab of sufficient thickness (i.e. greater than 18 inches).

Regards,

Scott

Adrian, MI

-----Original Message-----
From: William.Sherman@CH2M.com [mailto:William.Sherman@CH2M.com]
Sent: Thursday, September 04, 2008 3:36 PM
To: seaint@seaint.org
Subject: RE: Minimum Slab Reinforcing

The code does not refer to "each face", just to "area of shrinkage and temperature reinforcement" based on gross area of concrete. The "common" practice is to provide half of this area in each face as a minimum (except for thin slabs with one mat of steel). But the code doesn't say it has to be done this way - if the combined effect of the top and bottom steel areas meets the code minimum for S&T steel, then the code has been met. (You still have to provide tension steel in any face that has design tension.)

Bill Sherman

CH2M HILL / DEN

720-286-2792

From: William Haynes [mailto:gtg740p@gmail.com]
Sent: Thursday, September 04, 2008 1:15 PM
To: seaint@seaint.org
Subject: Re: Minimum Slab Reinforcing

If there is tension at the top and bottom, then you need to provide 0.0018*Ag at EACH face.

Will H.

On Thu, Sep 4, 2008 at 3:06 PM, David Topete <d.topete73@gmail.com> wrote:

I've always checked the 0.0018*Ag for top and bottom min steel. i.e., if i have a 24" thick footing (mat or grade beam), I'll check As,min top = 0.0018 * 12" * 24"/2 = 0.259 sq.in./ft. Use #4 @ 9"o.c., or something like that...

On Thu, Sep 4, 2008 at 11:28 AM, Josh Plummer <joshp@risatech.com> wrote:

In ACI 318, section 10.5.4, the code states that the minimum flexural reinforcement for slabs and footings should be the same as given in 7.12 (which is the temperature / shrinkage requirements).

I've interpreted this to me that regardless of what the area of steel required by analysis is, you can never let your total slab reinforcing (As_top + As_bottom) be less than the minimum amount required for temperature and shrinkage.

Now, I've got another engineer who is arguing that the Asmin = 0.0018 * Agross requirement applies for BOTH the top steel reinforcing and the bottom steel reinforcing. Since temperature and shrinkage controls the design of most relatively thick mat foundations, this interpretation would effectively double the amount of steel required in these mats.

Any opinions? Has anyone heard of someone interpreting this section of code in this manner? Is it common?

Sincerely,

Josh Plummer, SE

--
David Topete, SE

Re: Conc Admixtures

You can invite Powers Fasteners to come to your office for a presentation. Get a free lunch, technical data for an hour, a blue button doo hicky to get to their Appendix D software, and 0.5 C.E.U certificate....

-gm

On Thu, Sep 4, 2008 at 12:49 PM, William Haynes <gtg740p@gmail.com> wrote:

PCA has some method of earning CEU's that I had looked at before but never completed. There is a CEU contact listed on the registration form under the "Admixtures for Use in Concrete" module, for example. I am not sure exactly how they handle giving credit.

http://www.cement.org/learn/ln_distance.asp

On Thu, Sep 4, 2008 at 1:25 PM, Paul Feather <PFeather@se-solutions.net> wrote:

I need to get some CEU credit, and would love to actually do something useful.

Is anyone aware of a Continuing Education course or seminar that presents information on the specification and use of concrete admixtures?

Are any of the admixture reps doing office presentations like Hilti used to with their anchoring systems?

Paul Feather PE, SE

pfeather@SE-Solutions.net

www.SE-Solutions.net

Site Built Spiral Stair Case

I have been asked to provide calculations for this type of spiral stair
twice. The first one was built (it looked great), and the inspector never
asked for engineering. The second one I asked for a fee and time line the
contractor couldn't stomach, so they built something else. So, I still
don't know how to prove the design, but I have always been curious how to do
it.
I think given some time and research I could figure out the stresses. But,
what are the allowable shear and torsion values for the plywood beam? This
was always where I hit a dead end.
I'd be interested, Gerard, to hear how you handled this.

Dmitri Wright, PE
Cascade Engineering, Inc.
2459 SE TV Hwy, PMB #202
Hillsboro, OR 97123-7919
dmitri@cascade-structural.com
503-846-1131

Re: Conc Admixtures

PCA has some method of earning CEU's that I had looked at before but never completed. There is a CEU contact listed on the registration form under the "Admixtures for Use in Concrete" module, for example. I am not sure exactly how they handle giving credit.

http://www.cement.org/learn/ln_distance.asp

On Thu, Sep 4, 2008 at 1:25 PM, Paul Feather <PFeather@se-solutions.net> wrote:

I need to get some CEU credit, and would love to actually do something useful.

Is anyone aware of a Continuing Education course or seminar that presents information on the specification and use of concrete admixtures?

Are any of the admixture reps doing office presentations like Hilti used to with their anchoring systems?

Paul Feather PE, SE

pfeather@SE-Solutions.net

www.SE-Solutions.net

RE: Minimum Slab Reinforcing

The code does not refer to "each face", just to "area of shrinkage and temperature reinforcement" based on gross area of concrete. The "common" practice is to provide half of this area in each face as a minimum (except for thin slabs with one mat of steel). But the code doesn't say it has to be done this way - if the combined effect of the top and bottom steel areas meets the code minimum for S&T steel, then the code has been met. (You still have to provide tension steel in any face that has design tension.)

Bill Sherman

CH2M HILL / DEN

720-286-2792

From: William Haynes [mailto:gtg740p@gmail.com]
Sent: Thursday, September 04, 2008 1:15 PM
To: seaint@seaint.org
Subject: Re: Minimum Slab Reinforcing

If there is tension at the top and bottom, then you need to provide 0.0018*Ag at EACH face.

Will H.

On Thu, Sep 4, 2008 at 3:06 PM, David Topete <d.topete73@gmail.com> wrote:

I've always checked the 0.0018*Ag for top and bottom min steel. i.e., if i have a 24" thick footing (mat or grade beam), I'll check As,min top = 0.0018 * 12" * 24"/2 = 0.259 sq.in./ft. Use #4 @ 9"o.c., or something like that...

On Thu, Sep 4, 2008 at 11:28 AM, Josh Plummer <joshp@risatech.com> wrote:

In ACI 318, section 10.5.4, the code states that the minimum flexural reinforcement for slabs and footings should be the same as given in 7.12 (which is the temperature / shrinkage requirements).

I've interpreted this to me that regardless of what the area of steel required by analysis is, you can never let your total slab reinforcing (As_top + As_bottom) be less than the minimum amount required for temperature and shrinkage.

Now, I've got another engineer who is arguing that the Asmin = 0.0018 * Agross requirement applies for BOTH the top steel reinforcing and the bottom steel reinforcing. Since temperature and shrinkage controls the design of most relatively thick mat foundations, this interpretation would effectively double the amount of steel required in these mats.

Any opinions? Has anyone heard of someone interpreting this section of code in this manner? Is it common?

Sincerely,

Josh Plummer, SE

--
David Topete, SE

Re: Minimum Slab Reinforcing

But that doesn't refer to 10.5.4 where the 0.0018*Ag shows up.

Will

On Thu, Sep 4, 2008 at 3:26 PM, Scott, William N <William.N.Scott@conocophillips.com> wrote:

Years ago, Kris showed me Paragraph 10.5.3. "The requirements of 10.5.1 and 10.5.2 need not be applied if at every section As provided is atleast 1/3rd greater than that required by analysis."

I've used this provision in slabs to keep the tension reinforcing reasonable.

Bill Scott

From: Josh Plummer [mailto:joshp@risatech.com]
Sent: Thursday, September 04, 2008 10:29 AM
To: seaint@seaint.org
Subject: Minimum Slab Reinforcing

In ACI 318, section 10.5.4, the code states that the minimum flexural reinforcement for slabs and footings should be the same as given in 7.12 (which is the temperature / shrinkage requirements).

I've interpreted this to me that regardless of what the area of steel required by analysis is, you can never let your total slab reinforcing (As_top + As_bottom) be less than the minimum amount required for temperature and shrinkage.

Now, I've got another engineer who is arguing that the Asmin = 0.0018 * Agross requirement applies for BOTH the top steel reinforcing and the bottom steel reinforcing. Since temperature and shrinkage controls the design of most relatively thick mat foundations, this interpretation would effectively double the amount of steel required in these mats.

Any opinions? Has anyone heard of someone interpreting this section of code in this manner? Is it common?

Sincerely,

Josh Plummer, SE