Structural Engineering: 2007-12-16

Saturday, December 22, 2007

Re: FW: RE: technical References and Advice of CMU Wall Cracking

I cannot tell if there is any horizontal reinforcing.

There is likewise no sign of a control joint.

Thanks for the reply.

Jerold

-----Original Message-----
From: sscholl2@juno.com [mailto:sscholl2@juno.com]
Sent: Saturday, December 22, 2007 2:42 PM
To: seaint@seaint.org
Subject: RE: FW: RE: technical References and Advice of CMU Wall Cracking

Is there no horizontal reinforcing? We would use a min. of #4 @48" oc. plus
control joints (contraction joints), along with vertical reinf.

Stan Scholl, P.E.
Laguna Beach,CA
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RE: FW: RE: technical References and Advice of CMU Wall Cracking

Is there no horizontal reinforcing? We would use a min. of #4 @48" oc. plus control joints (contraction joints), along with vertical reinf.

Stan Scholl, P.E.
Laguna Beach,CA
_____________________________________________________________
Save hundreds on getting a Web Design Degree. Click here.
http://thirdpartyoffers.juno.com/TGL2111/fc/Ioyw6iigg17lDlKxhD6Cx7N7fymgdIlwZdtlIwZZKoxpZ1gtpywaPZ/

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Re: HSS welds

DSA has a bulliten about Chinese HSS seam welds.

-gm

On Dec 22, 2007 9:41 AM, Mark Johnson <markajohn@yahoo.com> wrote:

I think I remember reading a post about HSS with badly welded
seams but I can't seem to find it again.
Can anyone help me with that?

Thanks,

MJ

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-gm

Best Wishes

Friends,

I wish you all a merry Christmas.

For those of you who do not celebrate Christmas (and for those who do) I wish you all good health, happiness, and prosperity for 2008 and beyond.

My best regards,

H. Daryl Richardson

RE: FW: RE: technical References and Advice of CMU Wall Cracking

Hi Jerold,

If there is no out of plane deformation it sounds like contraction to me although I couldn't be sure, especially not having seen it. A horizontal string line can show lateral deflection and a plumb line, of course shows vertical movement. Can you check the outside at any point to confirm the same crack size on both sides? Do you know if it is solid grouted and what the reinforcing (especially the horizontal) is?

I would expect that a 35 foot wall would have an expansion crack or two. It may be that they ocurred under the posts because they divide the wall into equal segments and also because the vertical load and anchor bolts create a small stress concentration at that point which is just enough to provide a starting point to initiate the crack.

These are all just ideas for you to consider in your evaluation. It is always a judgement call and I certainly have not had a perfect score on the ones I have done.

Good Luck.

Richard

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 7:45 PM
To: seaint@seaint.org
Subject: Re: FW: RE: technical References and Advice of CMU Wall Cracking

Richard

Thanks for the reply, and the thoughtful questions.

The CMU is directly visible for inspection on the inside of the Crawlspace. And cracks are systematic every 12 feet under the 6x6 posts. On the exterior, there is stucco, and it periodically also shows cracking on the stucco face.

The cracks appear to be about the same width at the top as the bottom, and are mostly just a bit over hairline, but noticeable cracks nonetheless, that proceed as I mentioned earlier, pretty much straight down through the block, then a mortar joint, then a block, etc.

The two sides of the Residence are only about 35-40 feet long, so I discounted temperature shrinkage and expansion. Our climate here is fairly moderate also, with some freezing in the Winter, but not a lot.

The geometry of the walls is square (ordinary wrap around porches).

Thanks

Jerold

Original Message:
-----------------
From: Richard L. Hess RLHess@HessEng.com
Date: Fri, 21 Dec 2007 13:31:52 -0800
To: seaint@seaint.org
Subject: RE: technical References and Advice of CMU Wall Cracking

Jerold,
Are the cracks on both sides of the wall and of equal width? That is, could
they be caused by out of plane horizontal forces or a P-delta condition?
And, are there expansion joints or geometry to preclude contraction
cracking?
These are just two things that I look for with vertical cracks.
Richard Hess SE

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 12:11 PM
To: seaint@seaint.org
Subject: technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in
the perimeter masonry (CMU) walls of his home. The Builder has brought into
question my interpretation of what may have caused the cracking, so I wanted
to ask for some additional judgments and ideas, and possibly some forensic
references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft.
+/-) walls and interior CMU bearing piers. The interior bearing CMU piers
"look" adequate (40"x40") and the perimeter walls do not resist any lateral
grade loading from the perimeter (not retaining or basement walls), just a
tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and
porches span to 6x6 posts and then bear directly on the perimeter CMU wall.
Predominantly under each of these posts, a crack has developed. The cracks
are predominantly vertical.

My interpretation on what may have happened is that it does not appear to
be a settlement issue. I had often thought that a differential settlement
would expose itself with a masonry wall via cracking that is more "rainbow"
shaped and mostly along the mortar joints. Whereas a straight vertical
crack implies either overloading of the CMU wall or the effect of a sudden,
impact load (or combination of the two). In other words, it looks like a
brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding
references in my text books or on line to back up my interpretation that the
vertical crack is presumably due to an impact load or over loading from
above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is
eccentric and it allowable uplift resistance is less than the calculated net
uplift per my calculations, so it seems a very strong wind could have lifted
up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your
judgment.

Thank you

Jerold Taylor PE

Never miss a thing. Make Yahoo your homepage.

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HSS welds

I think I remember reading a post about HSS with badly welded
seams but I can't seem to find it again.
Can anyone help me with that?

Thanks,

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

Scott Threewitt is out of the office.

I will be out of the office starting Sat 12/22/2007 and will not return
until Thu 01/03/2008.

I will respond to your message when I return.

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

Jeff Giger/DAN/Minerals/METSO is out of the office.

I will be out of the office starting 12/21/2007 and will not return until
01/02/2008.

I will respond to your message when I return. For further needed assistance
call Barry Trumbauer at 271-7691 or Dave Ernest at 271-7665.

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

Friday, December 21, 2007

RE: FW: RE: technical References and Advice of CMU Wall Cracking

Still could be shrinkage cracks. Shrinkage in CMU can be due to just the curing process (it is concrete after all) or temperature effects. CMU can also move some due to moisture, but much less so than brick. With out control joints, every 12 feet kind of makes some sense for shrinkage cracks. If the CMU is relatively weak strength CMU units with stronger/good adhesion mortar, then you could see cracks that propogate through the units (i.e. the units fail in tension rather than the mortar bond failing in shear in the bed joints). Depending on how the CMU is attached to foundation (and whether you can actually see the interface between the CMU wall and the footing), if it is shrinkage cracks, they likely stop as you get close to the footing (the footing will potentially restrain the ability of the CMU to shrink over large distances where the CMU is connected to the footing).

Thus, without knowing more about the situation or seeing pictures, etc, my gut wants to say it is likely shrinkage cracking.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 10:45 PM
To: seaint@seaint.org
Subject: Re: FW: RE: technical References and Advice of CMU Wall Cracking

Richard

Thanks for the reply, and the thoughtful questions.

The CMU is directly visible for inspection on the inside of the Crawlspace. And cracks are systematic every 12 feet under the 6x6 posts. On the exterior, there is stucco, and it periodically also shows cracking on the stucco face.

The cracks appear to be about the same width at the top as the bottom, and are mostly just a bit over hairline, but noticeable cracks nonetheless, that proceed as I mentioned earlier, pretty much straight down through the block, then a mortar joint, then a block, etc.

The two sides of the Residence are only about 35-40 feet long, so I discounted temperature shrinkage and expansion. Our climate here is fairly moderate also, with some freezing in the Winter, but not a lot.

The geometry of the walls is square (ordinary wrap around porches).

Thanks

Jerold

Original Message:
-----------------
From: Richard L. Hess RLHess@HessEng.com
Date: Fri, 21 Dec 2007 13:31:52 -0800
To: seaint@seaint.org
Subject: RE: technical References and Advice of CMU Wall Cracking

Jerold,
Are the cracks on both sides of the wall and of equal width? That is, could
they be caused by out of plane horizontal forces or a P-delta condition?
And, are there expansion joints or geometry to preclude contraction
cracking?
These are just two things that I look for with vertical cracks.
Richard Hess SE

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 12:11 PM
To: seaint@seaint.org
Subject: technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in
the perimeter masonry (CMU) walls of his home. The Builder has brought into
question my interpretation of what may have caused the cracking, so I wanted
to ask for some additional judgments and ideas, and possibly some forensic
references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft.
+/-) walls and interior CMU bearing piers. The interior bearing CMU piers
“look” adequate (40”x40”) and the perimeter walls do not resist any lateral
grade loading from the perimeter (not retaining or basement walls), just a
tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and
porches span to 6x6 posts and then bear directly on the perimeter CMU wall.
Predominantly under each of these posts, a crack has developed. The cracks
are predominantly vertical.

My interpretation on what may have happened is that it does not appear to
be a settlement issue. I had often thought that a differential settlement
would expose itself with a masonry wall via cracking that is more “rainbow”
shaped and mostly along the mortar joints. Whereas a straight vertical
crack implies either overloading of the CMU wall or the effect of a sudden,
impact load (or combination of the two). In other words, it looks like a
brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding
references in my text books or on line to back up my interpretation that the
vertical crack is presumably due to an impact load or over loading from
above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is
eccentric and it allowable uplift resistance is less than the calculated net
uplift per my calculations, so it seems a very strong wind could have lifted
up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your
judgment.

Thank you

Jerold Taylor PE

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RE: technical References and Advice of CMU Wall Cracking

The house is approx. 35 ft. x 40 ft. Posts are spaced at approx. 10 ft – 12 ft. apart max.

There are no control joints. The posts and cracks are under each post at the aforementioned 10 ft. to 12 ft. apart.

The cracks are pretty much straight vertical and therefore go through the blocks themselves.

Jerold

From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Friday, December 21, 2007 6:45 PM
To: seaint@seaint.org
Subject: RE: technical References and Advice of CMU Wall Cracking

My initial thought is along the same line as Richard's second thought...maybe shrinkage cracks. How long at the two sides of the house with these posts? And how far apart are the posts/cracks? Are there any control joints in the CMU? Are the cracks in the CMU units themselves or the mortar joints?

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Richard L. Hess [mailto:RLHess@HessEng.com]
Sent: Friday, December 21, 2007 4:32 PM
To: seaint@seaint.org
Subject: RE: technical References and Advice of CMU Wall Cracking

Jerold,

Are the cracks on both sides of the wall and of equal width? That is, could they be caused by out of plane horizontal forces or a P-delta condition? And, are there expansion joints or geometry to preclude contraction cracking?

These are just two things that I look for with vertical cracks.

Richard Hess SE

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 12:11 PM
To: seaint@seaint.org
Subject: technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in the perimeter masonry (CMU) walls of his home. The Builder has brought into question my interpretation of what may have caused the cracking, so I wanted to ask for some additional judgments and ideas, and possibly some forensic references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft. +/-) walls and interior CMU bearing piers. The interior bearing CMU piers "look" adequate (40"x40") and the perimeter walls do not resist any lateral grade loading from the perimeter (not retaining or basement walls), just a tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and porches span to 6x6 posts and then bear directly on the perimeter CMU wall. Predominantly under each of these posts, a crack has developed. The cracks are predominantly vertical.

My interpretation on what may have happened is that it does not appear to be a settlement issue. I had often thought that a differential settlement would expose itself with a masonry wall via cracking that is more "rainbow" shaped and mostly along the mortar joints. Whereas a straight vertical crack implies either overloading of the CMU wall or the effect of a sudden, impact load (or combination of the two). In other words, it looks like a brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding references in my text books or on line to back up my interpretation that the vertical crack is presumably due to an impact load or over loading from above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is eccentric and it allowable uplift resistance is less than the calculated net uplift per my calculations, so it seems a very strong wind could have lifted up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your judgment.

Thank you

Jerold Taylor PE

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Re: FW: RE: technical References and Advice of CMU Wall Cracking

Richard

Thanks for the reply, and the thoughtful questions.

The CMU is directly visible for inspection on the inside of the Crawlspace. And cracks are systematic every 12 feet under the 6x6 posts. On the exterior, there is stucco, and it periodically also shows cracking on the stucco face.

The cracks appear to be about the same width at the top as the bottom, and are mostly just a bit over hairline, but noticeable cracks nonetheless, that proceed as I mentioned earlier, pretty much straight down through the block, then a mortar joint, then a block, etc.

The two sides of the Residence are only about 35-40 feet long, so I discounted temperature shrinkage and expansion. Our climate here is fairly moderate also, with some freezing in the Winter, but not a lot.

The geometry of the walls is square (ordinary wrap around porches).

Thanks

Jerold

Original Message:
-----------------
From: Richard L. Hess RLHess@HessEng.com
Date: Fri, 21 Dec 2007 13:31:52 -0800
To: seaint@seaint.org
Subject: RE: technical References and Advice of CMU Wall Cracking

Jerold,
Are the cracks on both sides of the wall and of equal width? That is, could
they be caused by out of plane horizontal forces or a P-delta condition?
And, are there expansion joints or geometry to preclude contraction
cracking?
These are just two things that I look for with vertical cracks.
Richard Hess SE

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 12:11 PM
To: seaint@seaint.org
Subject: technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in
the perimeter masonry (CMU) walls of his home. The Builder has brought into
question my interpretation of what may have caused the cracking, so I wanted
to ask for some additional judgments and ideas, and possibly some forensic
references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft.
+/-) walls and interior CMU bearing piers. The interior bearing CMU piers
"look" adequate (40"x40") and the perimeter walls do not resist any lateral
grade loading from the perimeter (not retaining or basement walls), just a
tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and
porches span to 6x6 posts and then bear directly on the perimeter CMU wall.
Predominantly under each of these posts, a crack has developed. The cracks
are predominantly vertical.

My interpretation on what may have happened is that it does not appear to
be a settlement issue. I had often thought that a differential settlement
would expose itself with a masonry wall via cracking that is more "rainbow"
shaped and mostly along the mortar joints. Whereas a straight vertical
crack implies either overloading of the CMU wall or the effect of a sudden,
impact load (or combination of the two). In other words, it looks like a
brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding
references in my text books or on line to back up my interpretation that the
vertical crack is presumably due to an impact load or over loading from
above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is
eccentric and it allowable uplift resistance is less than the calculated net
uplift per my calculations, so it seems a very strong wind could have lifted
up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your
judgment.

Thank you

Jerold Taylor PE

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Re: Shamefully Off-Topic: Carbon Christmas

The only question which really matters is the one about the sawtooth, question 9 I believe. If you understand that, and it is not rocket science, you win.

MERRY CHRISTMAS!

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

From: Jeff Smith

To: seaint@seaint.org

Sent: Friday, December 14, 2007 5:37 PM

Subject: RE: Shamefully Off-Topic: Carbon Christmas

I got 6 out of 10, what's a passing score?

From: Stan Caldwell [mailto:stancaldwell@gmail.com]
Sent: Friday, December 14, 2007 10:12 AM
To: SEAINT Listserv
Subject: Shamefully Off-Topic: Carbon Christmas

Recently, several of you have written passionately about sustainable design, reducing your carbon footprint, and similar nonsense.

Before you embarrass yourselves any further, I would urge you to take this Global Warming Test:

http://www.geocraft.com/WVFossils/GlobWarmTest/start.html

Then settle down with a good book (printed on real paper) before a roaring fire and ...

Have a Very Merry Christmas!

Politically Incorrect Stan

RE: CBC 2007 Wind Load

You could conceiveably have materials placed on the roof that are still in place when a wind event comes along. Bundle of roof shingles sitting on a roof would still be some what tough for high winds to move. Granted, the probability of a high wind event hitting when bundles of roof shingles are on the roof have to be pretty small, but...

Regards,

Scott

Adrian, MI

-----Original Message-----
From: David Topete [mailto:d.topete73@gmail.com]
Sent: Friday, December 21, 2007 4:02 PM
To: seaint@seaint.org
Subject: Re: CBC 2007 Wind Load

during a wind event, the roof will be replaced and/or maintained????

On Dec 21, 2007 12:44 PM, Adam Vakiener <avakiener@southernae.com> wrote:

>From: "Gerard Madden, SE" <gmse4603@gmail.com >
>To: seaint@seaint.org
>Subject: Re: CBC 2007 Wind Load

>------=_Part_17119_6443004.1198048052819
>Content-Type: text/plain; charset=ISO-8859-1
>Content-Transfer-Encoding: 7bit
>Content-Disposition: inline

>Who/what is on the roof causing live load during a wind event I ask?

Maintenance and construction materials.

--

Adam Vakiener, P.E.
Structural Engineer
Southern A&E, LLC

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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
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RE: technical References and Advice of CMU Wall Cracking

My initial thought is along the same line as Richard's second thought...maybe shrinkage cracks. How long at the two sides of the house with these posts? And how far apart are the posts/cracks? Are there any control joints in the CMU? Are the cracks in the CMU units themselves or the mortar joints?

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Richard L. Hess [mailto:RLHess@HessEng.com]
Sent: Friday, December 21, 2007 4:32 PM
To: seaint@seaint.org
Subject: RE: technical References and Advice of CMU Wall Cracking

Jerold,

Are the cracks on both sides of the wall and of equal width? That is, could they be caused by out of plane horizontal forces or a P-delta condition? And, are there expansion joints or geometry to preclude contraction cracking?

These are just two things that I look for with vertical cracks.

Richard Hess SE

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 12:11 PM
To: seaint@seaint.org
Subject: technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in the perimeter masonry (CMU) walls of his home. The Builder has brought into question my interpretation of what may have caused the cracking, so I wanted to ask for some additional judgments and ideas, and possibly some forensic references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft. +/-) walls and interior CMU bearing piers. The interior bearing CMU piers “look” adequate (40”x40”) and the perimeter walls do not resist any lateral grade loading from the perimeter (not retaining or basement walls), just a tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and porches span to 6x6 posts and then bear directly on the perimeter CMU wall. Predominantly under each of these posts, a crack has developed. The cracks are predominantly vertical.

My interpretation on what may have happened is that it does not appear to be a settlement issue. I had often thought that a differential settlement would expose itself with a masonry wall via cracking that is more “rainbow” shaped and mostly along the mortar joints. Whereas a straight vertical crack implies either overloading of the CMU wall or the effect of a sudden, impact load (or combination of the two). In other words, it looks like a brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding references in my text books or on line to back up my interpretation that the vertical crack is presumably due to an impact load or over loading from above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is eccentric and it allowable uplift resistance is less than the calculated net uplift per my calculations, so it seems a very strong wind could have lifted up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your judgment.

Thank you

Jerold Taylor PE

Never miss a thing. Make Yahoo your homepage.

RE: technical References and Advice of CMU Wall Cracking

Jerold,

Are the cracks on both sides of the wall and of equal width? That is, could they be caused by out of plane horizontal forces or a P-delta condition? And, are there expansion joints or geometry to preclude contraction cracking?

These are just two things that I look for with vertical cracks.

Richard Hess SE

-----Original Message-----
From: jerold taylor [mailto:jerold_taylor@yahoo.com]
Sent: Friday, December 21, 2007 12:11 PM
To: seaint@seaint.org
Subject: technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in the perimeter masonry (CMU) walls of his home. The Builder has brought into question my interpretation of what may have caused the cracking, so I wanted to ask for some additional judgments and ideas, and possibly some forensic references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft. +/-) walls and interior CMU bearing piers. The interior bearing CMU piers "look" adequate (40"x40") and the perimeter walls do not resist any lateral grade loading from the perimeter (not retaining or basement walls), just a tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and porches span to 6x6 posts and then bear directly on the perimeter CMU wall. Predominantly under each of these posts, a crack has developed. The cracks are predominantly vertical.

My interpretation on what may have happened is that it does not appear to be a settlement issue. I had often thought that a differential settlement would expose itself with a masonry wall via cracking that is more "rainbow" shaped and mostly along the mortar joints. Whereas a straight vertical crack implies either overloading of the CMU wall or the effect of a sudden, impact load (or combination of the two). In other words, it looks like a brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding references in my text books or on line to back up my interpretation that the vertical crack is presumably due to an impact load or over loading from above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is eccentric and it allowable uplift resistance is less than the calculated net uplift per my calculations, so it seems a very strong wind could have lifted up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your judgment.

Thank you

Jerold Taylor PE

Never miss a thing. Make Yahoo your homepage.

Re: CBC 2007 Wind Load

Do y'all get rain out there? In TX we have some of our worst rain storms with the highest winds. I've seen 3" dumped in 15 mins. Where that runs down the slope to the scuppers, it piles up. Did the forensic reports on a couple of the big ones...

jdc

>>> On 12/21/2007 at 2:44 PM, Adam Vakiener <avakiener@southernae.com> wrote:

>From: "Gerard Madden, SE" <gmse4603@gmail.com>
>To: seaint@seaint.org
>Subject: Re: CBC 2007 Wind Load

>------=_Part_17119_6443004.1198048052819
>Content-Type: text/plain; charset=ISO-8859-1
>Content-Transfer-Encoding: 7bit
>Content-Disposition: inline

>Who/what is on the roof causing live load during a wind event I ask?

Maintenance and construction materials.

--

Adam Vakiener, P.E.
Structural Engineer
Southern A&E, LLC

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Re: CBC 2007 Wind Load

during a wind event, the roof will be replaced and/or maintained????

On Dec 21, 2007 12:44 PM, Adam Vakiener <avakiener@southernae.com> wrote:

>From: "Gerard Madden, SE" <gmse4603@gmail.com >
>To: seaint@seaint.org
>Subject: Re: CBC 2007 Wind Load

>------=_Part_17119_6443004.1198048052819
>Content-Type: text/plain; charset=ISO-8859-1
>Content-Transfer-Encoding: 7bit
>Content-Disposition: inline

>Who/what is on the roof causing live load during a wind event I ask?

Maintenance and construction materials.

--

Adam Vakiener, P.E.
Structural Engineer
Southern A&E, LLC

******* ****** ******* ******** ******* ******* ******* ***
* 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
*
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* 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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--
David Topete, SE

Re: CBC 2007 Wind Load

>From: "Gerard Madden, SE" <gmse4603@gmail.com>
>To: seaint@seaint.org
>Subject: Re: CBC 2007 Wind Load

>------=_Part_17119_6443004.1198048052819
>Content-Type: text/plain; charset=ISO-8859-1
>Content-Transfer-Encoding: 7bit
>Content-Disposition: inline

>Who/what is on the roof causing live load during a wind event I ask?

Maintenance and construction materials.

Adam Vakiener, P.E.
Structural Engineer
Southern A&E, LLC

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

technical References and Advice of CMU Wall Cracking

In the recent past, I created a report for a Homeowner who has cracks in the perimeter masonry (CMU) walls of his home. The Builder has brought into question my interpretation of what may have caused the cracking, so I wanted to ask for some additional judgments and ideas, and possibly some forensic references that I could use to back up my assessment.

Specifically, the home is a very nice residence with tall perimeter (8 ft. +/-) walls and interior CMU bearing piers. The interior bearing CMU piers "look" adequate (40"x40") and the perimeter walls do not resist any lateral grade loading from the perimeter (not retaining or basement walls), just a tall crawlspace.

Around two sides of the perimeter, typically two levels of decking and porches span to 6x6 posts and then bear directly on the perimeter CMU wall. Predominantly under each of these posts, a crack has developed. The cracks are predominantly vertical.

My interpretation on what may have happened is that it does not appear to be a settlement issue. I had often thought that a differential settlement would expose itself with a masonry wall via cracking that is more "rainbow" shaped and mostly along the mortar joints. Whereas a straight vertical crack implies either overloading of the CMU wall or the effect of a sudden, impact load (or combination of the two). In other words, it looks like a brittle, sudden, overload crack.

This interpretation makes sense to me, but I am having a hard time finding references in my text books or on line to back up my interpretation that the vertical crack is presumably due to an impact load or over loading from above.

By the way, the 6x6 posts are anchored, but the Simpson tie used is eccentric and it allowable uplift resistance is less than the calculated net uplift per my calculations, so it seems a very strong wind could have lifted up the post and jolted it back down. We are in 130 mph, Exp. C location.

Please feel free to let me know if my interpretation is off base, in your judgment.

Thank you

Jerold Taylor PE

Never miss a thing. Make Yahoo your homepage.

Re: Design of Pavement Section

Bill,

You will probably find that an asphalt section will be less expensive, unless
labor for excavation is very high. There is quite a large difference in the
roadway section for different soils capacities in the subgrade material. It
would be best to have a Geotechnical Engineer give you some recommendations
or at least some R-values or CBR numbers to design the section from.

Where I'm working, we often get R-values in the 7-50 range. Seven is very low
but we've got some clayey or silty sands here (old farmground - good for farming
not so good for roads) With the low R-value material we have a highly travelled
5-lane road that has a section of 3 ft., 22" sub-base, 8" roadbase, and 6" asphalt.

For the standard highway district road section or local city road section, they use
12" roadbase and 3" asphalt. For a driveway that will see very infrequent heavy
truck loading, you might be able to get by with 8" roadbase and 2.5-3" asphalt, again
depending on the sub-grade soil strength. I've seen some soils that were good
enough to pave the 3" or 2.5" of asphalt right over the existing ground. (after
scraping off the topsoil, of course)

I hope that this helps. It looks like you've got many other responses about
concrete so I won't touch on that.

Take Care,
Lloyd Pack

On 20 Dec 2007 at 13:27, Bill Allen wrote:

>
> Don™t ask me why, but I need to design a driveway (on grade) for a
> fire truck. I believe the owner wants to use AC, but if he must go
> with PCC, then he will.
>
> Are there any good guidelines, references, methods used to design a
> section for this purpose? I sure would hate to waste a bunch of time
> if this is something that is pretty simple.
>
> I™m supposed to be receiving wheel loads later today.
>
> TIA,
>
> T. William (Bill) Allen, S.E.
> ALLEN DESIGNS
> Consulting Structural Engineers
> V (949) 248-8588 ¢ F(949) 209-2509

RE: Design of Pavement Section

Thanks, Gary.

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

ALLEN DESIGNS

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

-----Original Message-----
From: Gary Loomis [mailto:gloomis@MasterEngineersinc.com]
Sent: Thursday, December 20, 2007 2:13 PM
To: seaint@seaint.org
Subject: RE: Design of Pavement Section

“Concrete Floors on Ground” by Ralph E. Spears, PCA 1978 or the updated version “Concrete Floors on Ground”, EB075. Both have design charts for axles with single and dual wheels. We did a slab design for the local fire department 4 or 5 years ago. I think it was 8” think with wire mesh. We made sure the wire mesh was where it was suppose to be and wet cured the concrete. Also, put control joints at 15’. I was there last week and there are no cracks. It is holding up fine. But the PCA design guide walks you through the design.

Gary W. Loomis, P.E., Senior Structural Engineering

Master Engineers and Designers, Inc.

-----Original Message-----
From: Bill Allen [mailto:T.W.Allen@cox.net]
Sent: Thursday, December 20, 2007 4:31 PM
To: seaint@seaint.org
Subject: Design of Pavement Section

Don’t ask me why, but I need to design a driveway (on grade) for a fire truck. I believe the owner wants to use AC, but if he must go with PCC, then he will.

Are there any good guidelines, references, methods used to design a section for this purpose? I sure would hate to waste a bunch of time if this is something that is pretty simple.

I’m supposed to be receiving wheel loads later today.

TIA,

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

ALLEN DESIGNS

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

timber pedestrian bridge

There's a timber bridge clearinghouse called Wood in Transportation network
that's part of the USDA Forest Service. Here's a link:

http://www.fs.fed.us/na/wit/

They should have some helpful resources.

HTH

Buddy

p.s. I hope you all have a Merry Christmas.

From: Christopher Banbury [mailto:cbanbury@arkengineering.net]=20
Sent: Thursday, December 20, 2007 5:11 PM
To: seaint@seaint.org
Subject: timber pedestrian bridge

I need to design a pedestrian bridge to span a 40' slough in a local =
forest preserve area.
I'm not sure yet if the system will need to span the entire 40' or if it =
can be built as a boardwalk.
I have the Pedestrian Bridge & Walkway Design Guide from the Southern = Pine
Council.
The materials will need to be pulled or carried to the site so I'm not =
sure that full span GluLams are feasible.
The boardwalk solution is straight forward but I would appreciate any
recommendations for a full span system, timber or otherwise.
Thanks.

Christopher Banbury, PE
President

Ark Engineering, Inc.
PO Box 10129, Brooksville, FL 34603
22 North Broad ST, Brooksville, FL 34601
Phone: (352) 754-2424
Fax: (352) 754-2412
www.arkengineering.net

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

Thursday, December 20, 2007

Re: Design of Pavement Section

Assuming the soil is compacted well and well drained, I recommend
8" Concrete on 4" crushed rock, with 1.5" deep sawed joints about 15'o.c. in each direction. Cure with Hunts White and provide broom finish. Slope it 2% min.if outside, to avoid puddles. No vehicles on it for 14 days. Calcs. will verify this.

Stan Scholl, P.E.
Laguna Beach, CA
_____________________________________________________________
Click for free info on college degrees.
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RE: timber pedestrian bridge

You might want to look at a "traditional" timber framing option. If you need to do larger spans (whether full span or still partial spans), then you could look to do trusses. And many timber framers are somw what familiar with doing more "manual" lifting and assembly options that may not include heavy, modern equipment. Contact me "offline" (i.e. privately) if you want some possible contacts.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Christopher Banbury [mailto:cbanbury@arkengineering.net]
Sent: Thursday, December 20, 2007 5:11 PM
To: seaint@seaint.org
Subject: timber pedestrian bridge

I need to design a pedestrian bridge to span a 40’ slough in a local forest preserve area.

I’m not sure yet if the system will need to span the entire 40’ or if it can be built as a boardwalk.

I have the Pedestrian Bridge & Walkway Design Guide from the Southern Pine Council.

The materials will need to be pulled or carried to the site so I’m not sure that full span GluLams are feasible.

The boardwalk solution is straight forward but I would appreciate any recommendations for a full span system, timber or otherwise.

Thanks.

Christopher Banbury, PE

President

Ark Engineering, Inc.

PO Box 10129, Brooksville, FL 34603

22 North Broad ST, Brooksville, FL 34601

Phone: (352) 754-2424

Fax: (352) 754-2412

www.arkengineering.net

RE: Design of Pavement Section

Gary W. Loomis, P.E., Senior Structural Engineering

Master Engineers and Designers, Inc.

-----Original Message-----
From: Bill Allen [mailto:T.W.Allen@cox.net]
Sent: Thursday, December 20, 2007 4:31 PM
To: seaint@seaint.org
Subject: Design of Pavement Section

Don’t ask me why, but I need to design a driveway (on grade) for a fire truck. I believe the owner wants to use AC, but if he must go with PCC, then he will.

Are there any good guidelines, references, methods used to design a section for this purpose? I sure would hate to waste a bunch of time if this is something that is pretty simple.

I’m supposed to be receiving wheel loads later today.

TIA,

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

ALLEN DESIGNS

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