Structural Engineering: 2009-03-15

Saturday, March 21, 2009

Re: History of Seaint List

Rich Lewis wrote:
> PS: Bill, you're not the only one hunting! Watch your back . . . . and
> your neck!
I hear that once your head comes away from your shoulders...it's over.

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RE: Frozen soil = disturbed earth?

I would advocate that previously frozen soil is not disturbed soil in the classic definition. If you go back in time far enough, all soil was frozen. It occurred just after the dinosaurs.

You just can not or should not place soil on frozen soil. There are dilemmas out there like placing concrete foundations and then the structure is left for the winter with the intent of back filling and enclosing the structure in the spring. The foundations were not placed on frozen soil, but the soil was frozen after they were placed. In that case call a geotech.

Regards, Harold Sprague

Date: Fri, 20 Mar 2009 06:25:37 -0700
From: wilsonengineers@yahoo.com
Subject: Frozen soil = disturbed earth?
To: seaint@seaint.org

The easy CYA engineering answer is to require a soils engineer, do testing, compaction, etc. But sometimes the easy answer is not the right answer.

For example, one numbskull called me this winter with cracks in his foundation wall. Sure enough, he placed new concrete walls and footings in December, left them exposed and then we had sub-zero temps for about two months straight. Come February, the walls had several cracks. No wonder. But after the frost subsided, the cracks closed and didn't look like much of anything. Is there an argument that the foundation is okay (notwithstanding analysis of the cracks) because it returned to its original condition? Soils in our area are typically sandy gravel with decent bearing capacity.

Jim Wilson, PE

Stroudsburg, PA

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RE: OT - Taxes

Rich,

This is a tax deduction. On the third page, it says it deals with, among other things:

"Engineering or architectural services you perform in the United States in your engineering or architectural services trade or business ….

HTH

--- On Sat, 3/21/09, Rich Lewis <seaint04@lewisengineering.com> wrote:

From: Rich Lewis <seaint04@lewisengineering.com>
Subject: RE: OT - Taxes
To: seaint@seaint.org
Date: Saturday, March 21, 2009, 8:12 AM

Sorry, the default text of mark's message got screwed up in the last reply.

Mark,

Why don't you say what you're going after here instead of repeating the message? I read the first few paragraphs of the irs publication. It deals with the film industry. What does it have to do with engineering firms?

Rich

From: Mark Johnson [mailto:markajohn@yahoo.com]
Sent: Thursday, March 19, 2009 10:08 PM
To: seaint@seaint.org
Subject: OT - Taxes

I saw this:

http://www.irs.gov/pub/irs-pdf/i8903.pdf

on another group list. Some of the people there are filing amendments for past years too and coming up with some money. I haven't started my taxes yet but this looks promising.

MJ

RE: OT - Taxes

Sorry, the default text of mark's message got screwed up in the last reply.

Mark,

Why don't you say what you're going after here instead of repeating the message? I read the first few paragraphs of the irs publication. It deals with the film industry. What does it have to do with engineering firms?

Rich

From: Mark Johnson [mailto:markajohn@yahoo.com]
Sent: Thursday, March 19, 2009 10:08 PM
To: seaint@seaint.org
Subject: OT - Taxes

I saw this:

http://www.irs.gov/pub/irs-pdf/i8903.pdf

on another group list. Some of the people there are filing amendments for past years too and coming up with some money. I haven't started my taxes yet but this looks promising.

RE: History of Seaint List

We just change email addresses to keep Bill confused. There are quite a few
of us still lurking out there. We are still waiting for the Great
Gathering.

Rich

PS: Bill, you're not the only one hunting! Watch your back . . . . and
your neck!

-----Original Message-----
From: Bill Polhemus [mailto:bill@polhemus.cc]
Sent: Friday, March 20, 2009 7:17 PM
To: <seaint@seaint.org>
Subject: Re: History of Seaint List

I hunted them down, and I eliminated them.

There Can Be Only One.

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

On Mar 20, 2009, at 6:29 PM, <jwhite@megr.com> wrote:

> I was looking at the archives recently and was curious what some of
> the first posts were and who posted them. It was interesting to see
> that a lot of the questions are very similar to those being asked
> presently. The only major difference is the code references are
> older. The other thing I noticed was that Bill Polhemus is one of
> the only people active from the very beginning of the list to
> present day. I wonder what happened to many of the others who used
> to participate and also if any of those who are still on the list
> know how the list got started?
>
> - Jeremy
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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: OT - Taxes

Mark,

Rich

From: Mark Johnson [mailto:markajohn@yahoo.com]
Sent: Thursday, March 19, 2009 10:08 PM
To: seaint@seaint.org
Subject: OT - Taxes

I saw this:

http://www.irs.gov/pub/irs-pdf/i8903.pdf

on another group list. Some of the people there are filing amendments for past years too and coming up with some money. I haven't started my taxes yet but this looks promising.

Friday, March 20, 2009

RE: ACI Chapt. 22

I would say from strict reading of the code, it would be #3, whether it makes sense or not.

Regards,

Scott

Adrian, MI

From: Richard Calvert [mailto:RichardC@lbbe.com]
Sent: Tuesday, March 17, 2009 2:41 PM
To: seaint@seaint.org
Subject: ACI Chapt. 22

I’m trying to check a plain (unreinforced) concrete basement wall for a large point load. In Chapter 22 of the ACI-05 there appear to be two ways to approach this. The seemingly obvious approach is with Eq. 22-14 – but when considering the soil pressure and backing into the resultant vector, it does not occur within the middle-third of the wall, as required by section 22.6.3. Is this what it being stated by this section? So my next step is to use the equations per 22.5.3, as instructed in 22.6.3. but I find that the use of A1 instead of Ag gives a much lower allowable compression. The use of A1 in the context of a wall doesn’t make much sense to me. Is it acceptable to use Ag ILO of A1 in this case?

In other words, is the correct calculation:

22-14
22-14 + 22-2,3 (unity)
22-5 + 22-2,3
or
22-5(w/ Ag ILO of A1) + 22-2,3

Thanks,

Richard Calvert, EIT

Project Engineer

Fw: OT - Taxes

From: Mark Johnson <markajohn@yahoo.com>
Subject: OT - Taxes
To: seaint@seaint.org
Date: Thursday, March 19, 2009, 8:07 PM

I saw this:

http://www.irs.gov/pub/irs-pdf/i8903.pdf

on another group list. Some of the people there are filing amendments for past years too and coming up with some money. I haven't started my taxes yet but this looks promising.

MJ

Re: History of Seaint List

I hunted them down, and I eliminated them.

There Can Be Only One.

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

On Mar 20, 2009, at 6:29 PM, <jwhite@megr.com> wrote:

RE: Frozen soil = disturbed earth?

I should say the soil under the slab actually settled in spots and there were
voids between the slab and soil. They had to "mud jack" the slab to fix it.

-----Original Message-----
From: Haan, Scott M POA [mailto:Scott.M.Haan@usace.army.mil]
Sent: Friday, March 20, 2009 2:19 PM
To: seaint@seaint.org
Subject: RE: Frozen soil = disturbed earth?

--------------------------------------------------------------------------
Your following message has been delivered to the list
seaint@seaint.org at 15:21:36 on 20 Mar 2009.
--------------------------------------------------------------------------

I live in Alaska and had a friend put in a 4' foundation wall which was going
to have platform floor and crawlspace. He did not put the platform floor on
and backfilled and let it sit all winter and the wall cracked up. The soil
expanded and pushed inward on the wall. I have also seen foundation basement
walls kick in during the summer that did not have the platform floor built on
top.

I have seen a slab-on-grade that that settled badly after being placed on
frozen soil when the soil thawed. You cannot get 95% compaction when placing
frozen soil because the moisture has expanded 9% in granular soil and because
there are ice chunks in silt or clay. When it thaws and the water drains out
the ground settles under the weight of the slab and building contents. The
same thing would happen to footings placed on frozen soil.

Builders in Alaska frequently let foundations sit out all winter while they
are platform framing the unheated building on top without problems. The
footings are placed on thawed soil first. My theory is when the ground
freezes during the winter the foundation walls span between hard spots and
the wall settles when the building is heated and the the hard spots turn
soft. I think the foundation walls are normally not backfilled until the
ground thaws however and the foundations are normally heavily reinforced.

I haven't yet seen a problem here with foundation walls cracking up that sat
over the winter unless they were backfilled, but like I said the local
foundation walls and footings are heavily reinforced and the foundation walls
are normally 4 feet tall.

-----Original Message-----
From: Jim Wilson [mailto:wilsonengineers@yahoo.com]
Sent: Friday, March 20, 2009 5:26 AM
To: seaint@seaint.org
Subject: Frozen soil = disturbed earth?

Is previously frozen soil considered disturbed earth? Perhaps there isn't a
definitive answer to this question, but in general terms, if there is
evidence that the soil has frozen and heaved, is it thereafter unusable for
placement of a footing?

The easy CYA engineering answer is to require a soils engineer, do testing,
compaction, etc. But sometimes the easy answer is not the right answer.

For example, one numbskull called me this winter with cracks in his
foundation wall. Sure enough, he placed new concrete walls and footings in
December, left them exposed and then we had sub-zero temps for about two
months straight. Come February, the walls had several cracks. No wonder.
But after the frost subsided, the cracks closed and didn't look like much of
anything. Is there an argument that the foundation is okay (notwithstanding
analysis of the cracks) because it returned to its original condition? Soils
in our area are typically sandy gravel with decent bearing capacity.

Jim Wilson, PE
Stroudsburg, PA

RE: History of Seaint List

Many people read it, including the king of Zimbabwe who wants to give you his
inheretance.

-----Original Message-----
From: jwhite@megr.com [mailto:jwhite@megr.com]
Sent: Friday, March 20, 2009 3:29 PM
To: seaint@seaint.org
Subject: History of Seaint List

I was looking at the archives recently and was curious what some of the first
posts were and who posted them.  It was interesting to see that a lot of the
questions are very similar to those being asked presently.  The only major
difference is the code references are older.  The other thing I noticed was
that Bill Polhemus is one of the only people active from the very beginning
of the list to present day.  I wonder what happened to many of the others who
used to participate and also if any of those who are still on the list know
how the list got started?

- Jeremy

History of Seaint List

I was looking at the archives recently and was curious what some of the first posts were and who posted them. It was interesting to see that a lot of the questions are very similar to those being asked presently. The only major difference is the code references are older. The other thing I noticed was that Bill Polhemus is one of the only people active from the very beginning of the list to present day. I wonder what happened to many of the others who used to participate and also if any of those who are still on the list know how the list got started?

- Jeremy

RE: Frozen soil = disturbed earth?

-----Original Message-----
From: Jim Wilson [mailto:wilsonengineers@yahoo.com]
Sent: Friday, March 20, 2009 5:26 AM
To: seaint@seaint.org
Subject: Frozen soil = disturbed earth?

Re: Frozen soil = disturbed earth?

I'm no frost expert (although I once did design a major structure on permafrost), but does it make sense to build on once-frozen ground, since it could presumably freeze again -- not a Good Thing.

In other words, I'm suggesting building down below the frost depth. Duh.

Ralph Hueston Kratz, S.E.
Richmond CA USA

In a message dated 3/20/09 3:05:09 PM, Tom.Hunt@fluor.com writes:

Jim,

From perhaps a definition standpoint I would not consider frozen/unfrozen soil as disturbed soil as this would disqualify all soil north of Texas however this does not give you the green light in placing a foundation on known crappy soil. You can freeze and thaw good well graded/compacted soil all you want and nothing much will happen but take soil with some glacial till in it and you are in big trouble.

Thomas Hunt, S.E.
Fluor

Jim Wilson <wilsonengineers@yahoo.com>
03/20/2009 06:25 AM
Please respond to seaint To
seaint@seaint.org
cc

Subject
Frozen soil = disturbed earth?

Is previously frozen soil considered disturbed earth? Perhaps there isn't a definitive answer to this question, but in general terms, if there is evidence that the soil has frozen and heaved, is it thereafter unusable for placement of a footing?

The easy CYA engineering answer is to require a soils engineer, do testing, compaction, etc. But sometimes the easy answer is not the right answer.

For example, one numbskull called me this winter with cracks in his foundation wall. Sure enough, he placed new concrete walls and footings in December, left them exposed and then we had sub-zero temps for about two months straight. Come February, the walls had several cracks. No wonder. But after the frost subsided, the cracks closed and didn't look like much of anything. Is there an argument that the foundation is okay (notwithstanding analysis of the cracks) because it returned to its original condition? Soils in our area are typically sandy gravel with decent bearing capacity.

Jim Wilson, PE
Stroudsburg, PA

**************
Feeling the pinch at the grocery store? Make meals for Under $10. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000002)

Re: Frozen soil = disturbed earth?

Jim,

From perhaps a definition standpoint I would not consider frozen/unfrozen soil as disturbed soil as this would disqualify all soil north of Texas however this does not give you the green light in placing a foundation on known crappy soil. You can freeze and thaw good well graded/compacted soil all you want and nothing much will happen but take soil with some glacial till in it and you are in big trouble.

Thomas Hunt, S.E.
Fluor

Jim Wilson <wilsonengineers@yahoo.com>
03/20/2009 06:25 AM
Please respond to seaint

To	seaint@seaint.org
cc
Subject	Frozen soil = disturbed earth?

Is previously frozen soil considered disturbed earth? Perhaps there isn't a definitive answer to this question, but in general terms, if there is evidence that the soil has frozen and heaved, is it thereafter unusable for placement of a footing?

The easy CYA engineering answer is to require a soils engineer, do testing, compaction, etc. But sometimes the easy answer is not the right answer.

For example, one numbskull called me this winter with cracks in his foundation wall. Sure enough, he placed new concrete walls and footings in December, left them exposed and then we had sub-zero temps for about two months straight. Come February, the walls had several cracks. No wonder. But after the frost subsided, the cracks closed and didn't look like much of anything. Is there an argument that the foundation is okay (notwithstanding analysis of the cracks) because it returned to its original condition? Soils in our area are typically sandy gravel with decent bearing capacity.

Jim Wilson, PE
Stroudsburg, PA

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Re: Frozen soil = disturbed earth?

I guess there's at least one advantage of unreinforced concrete. ;)

Ralph

In a message dated 3/20/09 2:08:47 PM, wilsonengineers@yahoo.com writes:

Is previously frozen soil considered disturbed earth? Perhaps there isn't a definitive answer to this question, but in general terms, if there is evidence that the soil has frozen and heaved, is it thereafter unusable for placement of a footing?

The easy CYA engineering answer is to require a soils engineer, do testing, compaction, etc. But sometimes the easy answer is not the right answer.

For example, one numbskull called me this winter with cracks in his foundation wall. Sure enough, he placed new concrete walls and footings in December, left them exposed and then we had sub-zero temps for about two months straight. Come February, the walls had several cracks. No wonder. But after the frost subsided, the cracks closed and didn't look like much of anything. Is there an argument that the foundation is okay (notwithstanding analysis of the cracks) because it returned to its original condition? Soils in our area are typically sandy gravel with decent bearing capacity.

Jim Wilson, PE
Stroudsburg, PA

**************
Feeling the pinch at the grocery store? Make meals for Under $10. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000002)

Frozen soil = disturbed earth?

The easy CYA engineering answer is to require a soils engineer, do testing, compaction, etc. But sometimes the easy answer is not the right answer.

Jim Wilson, PE

Stroudsburg, PA

Thursday, March 19, 2009

Re: Concrete and Vibration

Many thanks Josh.

On Thu, Mar 19, 2009 at 10:02 AM, Josh Plummer <joshp@risatech.com> wrote:

Gerard -

There is an ATC (Applied Technology Council) publication on floor
vibrations. It was published in 1999. Based on the table of contents this
publication is meant to cover light frame and concrete construction as well
as steel. I see examples on precast stadium seating, glulam dance floors,
hollow core office, precast Double-T footbridge, Wood truss, wood i-joists.

Honestly, it will probably be very similar to the AISC design guide. After
all, two of the three authors (Dave Allen and Tom Murray) were responsible
for the other AISC publication.

One word of caution: I ordered a copy a while back.... But, I think ATC's
on-line ordering system was screwed up and I never received it. Thankfully,
I was never charged for it either. Regardless, don't be surprised if you
have to phone in or fax in an order to actually get it processed.

Sincerely,

Josh Plummer, SE

RISA Technologies
joshp@risatech.com
(949) 951-5815 (voice)
(949) 951-5848 (fax)

--------------------------------------------------------------------------
--------------------------------------------------------------------------
Subject: Concrete and Vibration
From: "Gerard Madden, SE" <gmse4603@gmail.com>
To: seaint@seaint.org

Anyone know of a good reference for evaluating concrete systems (flat plates
and/or slab and beams) for vibrations for laboratory equipment, like a
concrete version of Design Guide 11 for steel?

TIA
-gm

******* ****** ******* ******** ******* ******* ******* ***
* 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: Concrete and Vibration

Gerard -

There is an ATC (Applied Technology Council) publication on floor
vibrations. It was published in 1999. Based on the table of contents this
publication is meant to cover light frame and concrete construction as well
as steel. I see examples on precast stadium seating, glulam dance floors,
hollow core office, precast Double-T footbridge, Wood truss, wood i-joists.

Honestly, it will probably be very similar to the AISC design guide. After
all, two of the three authors (Dave Allen and Tom Murray) were responsible
for the other AISC publication.

One word of caution: I ordered a copy a while back.... But, I think ATC's
on-line ordering system was screwed up and I never received it. Thankfully,
I was never charged for it either. Regardless, don't be surprised if you
have to phone in or fax in an order to actually get it processed.

Sincerely,

Josh Plummer, SE

RISA Technologies
joshp@risatech.com
(949) 951-5815 (voice)
(949) 951-5848 (fax)

--------------------------------------------------------------------------
--------------------------------------------------------------------------
Subject: Concrete and Vibration
From: "Gerard Madden, SE" <gmse4603@gmail.com>
To: seaint@seaint.org

Anyone know of a good reference for evaluating concrete systems (flat plates
and/or slab and beams) for vibrations for laboratory equipment, like a
concrete version of Design Guide 11 for steel?

TIA
-gm

Wednesday, March 18, 2009

Re: Cold-formed corrugated

Gordon

If it is feasible maybe the Simpson Steel Strong Walls made out of the corrugated steel might work.

Joe Venuti
Johnson & Nielsen Associates
Palm Springs, CA

In a message dated 3/18/2009 10:43:35 A.M. Pacific Daylight Time, GordonGoodell@harmonydesigninc.com writes:

Bill, David, Drew, Jim, et al,

Thanks for your input on cold-formed steel shear values and appropriate R-values. My investigation leads me to believe that I should not count on anything from this pre-fab structure, so I'm looking at other options. There are several.

Jim, I looked online for the MCA primer, which I would be interested in regardless of whether I learn anything that might help on this job or not. My experience with corrugated decks thus far has always been using them filled with structural concrete. I assume the primer also provides guidance for using bare decks for shear. They want $100 for it...do you think it's worth it?

thanks,

Gordon

From: Jim Wilson [mailto:wilsonengineers@yahoo.com]
Sent: Tuesday, March 17, 2009 3:25 PM
To: seaint@seaint.org
Subject: Re: Cold-formed corrugated

Gordon,

You can find design theories and exact detailed examples on how to do this if you can get your hands on a copy of "A Primer on Diaphragm Design" from the Metal Construction Association. Its a bit tricky the first time through but it really works out nicely. If I recall correctly, it can also be made into spreadsheet form without too much work.

Jim Wilson, PE

Stroudsburg, PA

From: Gordon Goodell <GordonGoodell@harmonydesigninc.com>
To: seaint@seaint.org
Sent: Tuesday, March 17, 2009 2:47:15 PM
Subject: Cold-formed corrugated

I have a client who wants to use an "unengineered agricultural building" made of cold-formed steel as most of the envelope for a large woodshop. I have my roof diaphragm problems solved, because it's being furred out & covered w/ plywood (underside). Does anyone have experience using corrugated metal for shearwalls? It seems like the 4 ½", 20ga corrugated partition panels supplied with the kit should have a lot of shear resistance if connected properly. If I could prove it, it would be a shame to require wood shearwalls to be built right beside them.

thanks,

Gordon Goodell

Feeling the pinch at the grocery store? Make dinner for $10 or less.

RE: Cold-formed corrugated

Bill, David, Drew, Jim, et al,

Thanks for your input on cold-formed steel shear values and appropriate R-values. My investigation leads me to believe that I should not count on anything from this pre-fab structure, so I'm looking at other options. There are several.

Jim, I looked online for the MCA primer, which I would be interested in regardless of whether I learn anything that might help on this job or not. My experience with corrugated decks thus far has always been using them filled with structural concrete. I assume the primer also provides guidance for using bare decks for shear. They want $100 for it...do you think it's worth it?

thanks,

Gordon

From: Jim Wilson [mailto:wilsonengineers@yahoo.com]
Sent: Tuesday, March 17, 2009 3:25 PM
To: seaint@seaint.org
Subject: Re: Cold-formed corrugated

Gordon,

You can find design theories and exact detailed examples on how to do this if you can get your hands on a copy of "A Primer on Diaphragm Design" from the Metal Construction Association. Its a bit tricky the first time through but it really works out nicely. If I recall correctly, it can also be made into spreadsheet form without too much work.

Jim Wilson, PE

Stroudsburg, PA

From: Gordon Goodell <GordonGoodell@harmonydesigninc.com>
To: seaint@seaint.org
Sent: Tuesday, March 17, 2009 2:47:15 PM
Subject: Cold-formed corrugated

I have a client who wants to use an "unengineered agricultural building" made of cold-formed steel as most of the envelope for a large woodshop. I have my roof diaphragm problems solved, because it's being furred out & covered w/ plywood (underside). Does anyone have experience using corrugated metal for shearwalls? It seems like the 4 ½", 20ga corrugated partition panels supplied with the kit should have a lot of shear resistance if connected properly. If I could prove it, it would be a shame to require wood shearwalls to be built right beside them.

thanks,

Gordon Goodell

Rigid vs. Semi-Rigid Joint

Is this defined anywhere? I seem to recall 0.002 Radians and 0.004 Radians respectively, but I don't recall where that came from. It might be from FEMA, but that was a long time ago.

TIA,

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

ALLEN DESIGNS

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

Re: Concrete and Vibration

Hi Jim,

Appreciate the comments. Thanks.

I found a couple of articles on line, it appears it actually performs pretty well for vibration when compared to metal deck and concrete fill/steel framed floors. There is also a book I found at concrete.org.uk on the subject "A Design Guide for Footfall Induced Vibration of Structures" ... anyone familiar with the book and care to give me a review on usefulness?

-gm

On Wed, Mar 18, 2009 at 4:32 AM, Jim Getaz <jgetaz@shockeyprecast.com> wrote:

        Gerard,

                We have extrapolated AISC DG 11 to work for concrete beams and slabs. E changes, but most other things, e.g, mass and I, are just parameters.

        HTH,

        Jim Getaz

RE: ACI Chapt. 22

If this is a residential basement, you might check ACI 332, Residential Concrete. It may offer a slightly different, simpler approach.

Jerry D. Coombs, P.E.
Coombs Engineering Services
Structural Engineer
1710 Stonecrest Trail
Wylie, TX 75098
214-287-4696

From: Richard Calvert [mailto:RichardC@lbbe.com]
Sent: Tuesday, March 17, 2009 1:41 PM
To: seaint@seaint.org
Subject: ACI Chapt. 22

In other words, is the correct calculation:

22-14
22-14 + 22-2,3 (unity)
22-5 + 22-2,3
or
22-5(w/ Ag ILO of A1) + 22-2,3

Thanks,

Richard Calvert, EIT

Project Engineer

Re: Concrete and Vibration

Gerard,

We have extrapolated AISC DG 11 to work for concrete beams and slabs. E changes, but most other things, e.g, mass and I, are just parameters.

HTH,

Jim Getaz

Tuesday, March 17, 2009

RE: Cold-formed corrugated

I think that, in theory, you should be able to design for R=1.0 and not
worry about classification, but the best place I've found for a "catch all"
is Table 15.4-2 at the very bottom. I know this is for non-building
structures, but the last item seems to catch just about everything that
doesn't fall into a specific category and is in the spirit of R~1.0.

Better yet, I believe you could use Table 12.2-1 item A.14 with an R=2, but
Section 14.1 might jump up and bite the OP.

T. William (Bill) Allen, S.E.
ALLEN DESIGNS
Consulting Structural Engineers
V (949) 248-8588 • F(949) 209-2509

-----Original Message-----
From: Drew Morris [mailto:dmorris@bbfm.com]
Sent: Tuesday, March 17, 2009 2:36 PM
To: seaint@seaint.org
Subject: Re: Cold-formed corrugated

Bill, I'm not sure about the R=1.25. Where does that come from.
Otherwise I agree with your comment on designing per ESR 3056.

Bill Allen wrote:
> Drew -
>
> Couldn't he (the OP) design based on R=1.25? I bet wind governs. If so, he
> could then determine the diaphragm and SW capacities based on ICC ESR
3056,
> right? Sure, he may have to add/replace fasteners, but that's better than
> building a new wood SW inside (and providing the requisite connections).
>
> Just my two cents.
>
>
> T. William (Bill) Allen, S.E.
> ALLEN DESIGNS
> Consulting Structural Engineers
> V (949) 248-8588 • F(949) 209-2509
>
> -----Original Message-----
> From: Drew Morris [mailto:dmorris@bbfm.com]
> Sent: Tuesday, March 17, 2009 12:05 PM
> To: seaint@seaint.org
> Subject: Re: Cold-formed corrugated
>
> I don't believe there are any assemblies of this type that are in the
> IBC. I think you can design the building using a R=3 if you are in SDC B
> or C, see ASCE 7-05 Table 12.2-1. You would need some test reports for
> the allowable shearwall values.
>
> Gordon Goodell wrote:
>
>> I have a client who wants to use an "unengineered agricultural
>> building" made of cold-formed steel as most of the envelope for a
>> large woodshop. I have my roof diaphragm problems solved, because it's
>> being furred out & covered w/ plywood (underside). Does anyone have
>> experience using corrugated metal for shearwalls? It seems like the 4
>> ½", 20ga corrugated partition panels supplied with the kit should have
>> a lot of shear resistance if connected properly. If I could prove it,
>> it would be a shame to require wood shearwalls to be built right
>> beside them.
>>
>> thanks,
>>
>> Gordon Goodell
>>
>>
>
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RE: ACI Chapt. 22

I’m not sure if I’m addressing your question correctly. As I understand it you want to know if the eccentricity of the axial force can be outside the middle third of the wall thickness. I would look at this as the virtual eccentricity of the load P caused by moment. If this is what you’re asking then I believe the reason you must stay within the middle third of the wall thickness is so that there is no tension force in the wall. When the virtual eccentricity exceeds 1/6 from the centerline of the wall there is tension stress in the concrete.

Rich

From: Richard Calvert [mailto:RichardC@lbbe.com]
Sent: Tuesday, March 17, 2009 1:41 PM
To: seaint@seaint.org
Subject: ACI Chapt. 22

In other words, is the correct calculation:

22-14
22-14 + 22-2,3 (unity)
22-5 + 22-2,3
or
22-5(w/ Ag ILO of A1) + 22-2,3

Thanks,

Richard Calvert, EIT

Project Engineer

Re: Cold-formed corrugated

Bill, I'm not sure about the R=1.25. Where does that come from.
Otherwise I agree with your comment on designing per ESR 3056.

Bill Allen wrote:
> Drew -
>
> Couldn't he (the OP) design based on R=1.25? I bet wind governs. If so, he
> could then determine the diaphragm and SW capacities based on ICC ESR 3056,
> right? Sure, he may have to add/replace fasteners, but that's better than
> building a new wood SW inside (and providing the requisite connections).
>
> Just my two cents.
>
>
> T. William (Bill) Allen, S.E.
> ALLEN DESIGNS
> Consulting Structural Engineers
> V (949) 248-8588 • F(949) 209-2509
>
> -----Original Message-----
> From: Drew Morris [mailto:dmorris@bbfm.com]
> Sent: Tuesday, March 17, 2009 12:05 PM
> To: seaint@seaint.org
> Subject: Re: Cold-formed corrugated
>
> I don't believe there are any assemblies of this type that are in the
> IBC. I think you can design the building using a R=3 if you are in SDC B
> or C, see ASCE 7-05 Table 12.2-1. You would need some test reports for
> the allowable shearwall values.
>
> Gordon Goodell wrote:
>
>> I have a client who wants to use an "unengineered agricultural
>> building" made of cold-formed steel as most of the envelope for a
>> large woodshop. I have my roof diaphragm problems solved, because it's
>> being furred out & covered w/ plywood (underside). Does anyone have
>> experience using corrugated metal for shearwalls? It seems like the 4
>> ½", 20ga corrugated partition panels supplied with the kit should have
>> a lot of shear resistance if connected properly. If I could prove it,
>> it would be a shame to require wood shearwalls to be built right
>> beside them.
>>
>> thanks,
>>
>> Gordon Goodell
>>
>>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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:
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> *
> * 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
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>

Re: Cold-formed corrugated

Gordon,

Jim Wilson, PE

Stroudsburg, PA

From: Gordon Goodell <GordonGoodell@harmonydesigninc.com>
To: seaint@seaint.org
Sent: Tuesday, March 17, 2009 2:47:15 PM
Subject: Cold-formed corrugated

thanks,

Gordon Goodell

Concrete and Vibration

Anyone know of a good reference for evaluating concrete systems (flat plates and/or slab and beams) for vibrations for laboratory equipment, like a concrete version of Design Guide 11 for steel?

TIA
-gm