Structural Engineering: 2008-03-16

Saturday, March 22, 2008

IBC Eq 21-3

Sometimes it is best to post a question and then the obvious answer jumps out at you.

Please disregard the question - it still is not defined in the current code, but the UBC world has it defined as the modular ratio, Es/Em which in the IBC world is just incorporated into the equations as Es/Em instead of "n". Like I thought in the original question, I was just making things too complex.

Thanks,

Jared

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IBC Eq 21-3

Dear list:

I think this is one of those incredibly simple questions that I am just making too complex. I have been typically doing masonry design using the strength provisions. I am looking at an existing building probably designed using the allowable stress provisions, so I am back checking the original design using allowable stress design and the current code procedures/limitations. The IBC and ASCE 7 modify ACI 530-05 by adding a maximum tension reinforcing ratio in Eq. 21-3. I do not see where any of the documents define the "n value" in Eq. 21-3. Can anyone steer me in the right direction?

Thanks in advance.

Jared

RE: review of another SE's design...

We are mandated to contact the engineer and inform that we are to do a review on his/her work. I.e. open up a line of communication and ethically respect the other.

Thor A. Tandy P.Eng, MIStructE, Struct.Eng
Victoria, BC
Canada
vicpeng@telus.net

-----Original Message-----
From: Andrew Kester, P.E. [mailto:akester@cfl.rr.com]
Sent: Friday, March 21, 2008 1:26 PM
To: seaint
Subject: review of another SE's design...

Please email any comments or suggestions directly to me, as this is a weekend job...

I have been asked to review, from what I know, a respected long-time engineer in this area's job. It is a pretty big project, with some steel framing issues. The GC has hired us to investigate the steel that has been erected on-site (done), run some calcs on their steel sizes, and come up with some professional opinions in a report for a Monday afternoon as to what we think has occurred and how to fix it. They said they quote, "We do not care who is right or wrong, we have two parties pointing fingers, and we want your unbiased opinion.,"

It is a precarious position but at least I do not feel hamstrung. I want to be delicate, professional, and not hang another engineer out to dry.

I guess I am asking for opinions, ideas, experiences of who has been through this before...

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

Re: review of another SE's design...

Andrew:

Excellent advice provided by the members of this list, as usual.

I am asked to perform this service fairly often and to be honest, I
typically decline this kind of work.

I'd rather just do my own work than be a critic.

But, if you are in a crunch, I really think you should insist on some kind
of "hold harmless" agreement between you and the owner to limit your
exposure, because if you do get pulled into litigation, you will still
have to cover your legal expenses and time lost.

Even if you HAVE insurance, you will still have to staisfy your deductable
and defense costs disbursed by the O/E company will still count against
you come renewal time.

UGH.

When clients come to me for this, my response is "why didn't you hire me
in the first place?"

Also, as Mr. Richardson correctly pointed out, check the Florida BOPE
rules on this...if you do not notify the other firm of the peer review,
you may be committing an ethics violation.

I welcome peer reviews on my work; its nice to have a second look at
things and, frankly, it makes us look even better when there are no
issues.

dlf

> Andrew,
>
> Both Chris and Harold have offered good advice. I do, however,
> have a couple of things to add.
>
> In Alberta it would be ethically required for you to notify the
> other engineer that you have been requested of provide a review or
second opinion of his/her work. That is, unless you are working for a
lawyer and "client/lawyer confidences are involved in which case such
notification could possibly be illegal.
>
> If there is anything wrong there will likely be litigation and
you
> will almost certainly be drawn into it. I would recommend that
> you have insurance in place before you undertake the work;and,
> under no circumstances assign any blame to anyone for anything as Chris
recommended (That would be for the litigation to determine).
> If you must (and, quite possibly you must) provide a fast reply
> and don't have sufficient time to properly assess some items
> qualify them as "concerns that require a more detailed review than time
has permitted for this report."
>
> Regards,
>
> H. Daryl Richardson
> ----- Original Message -----
> From: Harold Sprague
> To: seaint@seaint.org
> Sent: Friday, March 21, 2008 4:00 PM
> Subject: RE: review of another SE's design...
>
>
> It is difficult to advise based on the limited information. But I
will
> offer a few observations.
>
> The report should focus on the technical aspects and avoid who should
> have done what. That may be an issue later. Write in the third person.
>
> Try to be as dispassionate as possible. If this is a failure or short
> coming of some sort, there are some guidelines published by CASE. There
are also some documents from ASTM: E 620, E 678, E 1658, E 1732 that may
be helpful.
>
> I would also recommend the book "Engineering Ethics - Concepts ,
> Viewpoints, Cases and Codes", by the National Institute for Engineering
Ethics at Texas Tech.
>
> Regards,
> Harold Sprague
>
>
>
>
> ----------------------------------------------------------------------------
> From: akester@cfl.rr.com
> To: seaint@seaint.org
> Subject: review of another SE's design...
> Date: Fri, 21 Mar 2008 17:26:13 -0400
>
>
> Please email any comments or suggestions directly to me, as this is
a
> weekend job...
>
> I have been asked to review, from what I know, a respected long-time
> engineer in this area's job. It is a pretty big project, with some steel
framing issues. The GC has hired us to investigate the steel that has
been erected on-site (done), run some calcs on their steel sizes, and
come up with some professional opinions in a report for a Monday
afternoon as to what we think has occurred and how to fix it. They said
they quote, "We do not care who is right or wrong, we have two parties
pointing fingers, and we want your unbiased opinion.,"
>
> It is a precarious position but at least I do not feel hamstrung. I
> want to be delicate, professional, and not hang another engineer out to
dry.
>
> I guess I am asking for opinions, ideas, experiences of who has been
> through this before...
>
>
> Andrew Kester, P.E.
> Principal/Project Manager
> ADK Structural Engineering, PLLC
> 1510 E. Colonial Ave., Suite 301
> Orlando, FL 32803
>
>
>
> ------------------------------------------------------------------------------
> How well do you know your celebrity gossip? Talk celebrity smackdowns
> here.

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

Re: Structural Concrete subject to sub zero temp. conditions

Dear Mr. Harold,

Thanks a lot for the information. You are right, the pump foundation is not subject to cyclic temparature effect. As this is a harded concrete subject to ice cover, we felt, there should not be any structural deteroiration. Hence we planned to inspect the fundation top surface for any cracks at the next opportunity. I think your suggestion of hammer test, using a brass hammer, would give us confidence on the condition of the concrete.

Best Regards

Lakshmana RK Nukala

On Fri, Mar 21, 2008 at 7:07 PM, Harold Sprague <spraguehope@hotmail.com> wrote:

The problem with freezing concrete that was cured prior to exposure is freeze thaw cycling as opposed to a steady state freeze. Any concrete that is cycling freezing and thawing can exhibit problems if it is not air entrained. What you are describing does not appear to be cycling. It is only unfrozen on rare occassions that the pump is out of service.

The integrity can be routinely checked by whacking the surface with a hammer. Sound concrete will have a definite ring. Freeze damaged concrete will be a thud. It is very distinctive. You can get an NDT test using impulse response. That will tell you if you have consistant concrete. Freeze damaged concrete will have a different response than sound concrete. But I would elect to just whack it with a hammer. If that shows damage then get the NDT.
http://olsonengineering.com

Concrete that is subject to freeze thaw cycling should be air entrained. You may have some level of air entrainment allready. It is often used to aid pumping. If you are unsure or want to be more definitive, a petrographic examination can determine the level of air entrainment.

Regards,
Harold Sprague

Date: Mon, 17 Mar 2008 22:20:52 +0300
From: lakshmana.nukala@gmail.com
To: seaint@seaint.org
Subject: Re: Structural Concrete subject to sub zero temp. conditions

Jerry & Daryl,

Thanks alot for responding to my mail, and for the offered info.

The foundation was cast and cured as per spec,(QC confirm the 28day strength), after commissioning of the plant, the Ice formation has started.  Actually It was hhardened concrete.  foundation foot print is about 1.5mX 0.8mX1.0mdeep, it supports a critical pump in LNG process plant. Hence the integrity of the foundation is big concern. This fdn is subject to ice formation about 2 years ago, and was continuously under same condition, expect for plant down time.

I have following questions,

1.   As this is a hardened concrete, and due to smaller size, can I ignore the effect of freezing of entrapped moisture?

2.  we have to leave it same condition due to operational aspect, how would i ensure the integrity of the foundation?

Any suggestion and references would be highly appreciated.

Best Regards

Lakshmana RK Nukala

On Mon, Mar 17, 2008 at 3:14 PM, Jerry Coombs <JCoombs@carollo.com> wrote:

When was it frozen? Did the uncured fndn freeze and at what point?   How big (all directions) is the footing? How critical is said footing? You can't place fresh concrete on a surface below freezing temp. Has to be thawed, warmed and thermally protected afterward.

>>> On 3/16/2008 at 1:24 PM, "Lakshmana Nukala" <lakshmana.nukala@gmail.com> wrote:

Dear All,

We are facing a situation, where the top 3 to 4 inch depth of top surface of a concrete foundation for pump is covered with ice formation.

Original design had never anticipated this situation, hence normal M35 grade concrete is used for this foundation. Surface temp of the concrete fdn found to be above -20 Degree C,

Any input or reference to to handle this situation would be great help for me.

Best Regards

Lakshmana RK Nukala

Test your Star IQ Play now!

Friday, March 21, 2008

Re: review of another SE's design...

Andrew,

Both Chris and Harold have offered good advice. I do, however, have a couple of things to add.

In Alberta it would be ethically required for you to notify the other engineer that you have been requested of provide a review or second opinion of his/her work. That is, unless you are working for a lawyer and "client/lawyer confidences are involved in which case such notification could possibly be illegal.

If there is anything wrong there will likely be litigation and you will almost certainly be drawn into it. I would recommend that you have insurance in place before you undertake the work;and, under no circumstances assign any blame to anyone for anything as Chris recommended (That would be for the litigation to determine). If you must (and, quite possibly you must) provide a fast reply and don't have sufficient time to properly assess some items qualify them as "concerns that require a more detailed review than time has permitted for this report."

Regards,

H. Daryl Richardson

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

From: Harold Sprague

To: seaint@seaint.org

Sent: Friday, March 21, 2008 4:00 PM

Subject: RE: review of another SE's design...

It is difficult to advise based on the limited information. But I will offer a few observations.

The report should focus on the technical aspects and avoid who should have done what. That may be an issue later. Write in the third person.

Try to be as dispassionate as possible. If this is a failure or short coming of some sort, there are some guidelines published by CASE. There are also some documents from ASTM: E 620, E 678, E 1658, E 1732 that may be helpful.

I would also recommend the book "Engineering Ethics - Concepts , Viewpoints, Cases and Codes", by the National Institute for Engineering Ethics at Texas Tech.

Regards,
Harold Sprague

From: akester@cfl.rr.com
To: seaint@seaint.org
Subject: review of another SE's design...
Date: Fri, 21 Mar 2008 17:26:13 -0400

Please email any comments or suggestions directly to me, as this is a weekend job...

I have been asked to review, from what I know, a respected long-time engineer in this area's job. It is a pretty big project, with some steel framing issues. The GC has hired us to investigate the steel that has been erected on-site (done), run some calcs on their steel sizes, and come up with some professional opinions in a report for a Monday afternoon as to what we think has occurred and how to fix it. They said they quote, "We do not care who is right or wrong, we have two parties pointing fingers, and we want your unbiased opinion.,"

It is a precarious position but at least I do not feel hamstrung. I want to be delicate, professional, and not hang another engineer out to dry.

I guess I am asking for opinions, ideas, experiences of who has been through this before...

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

How well do you know your celebrity gossip? Talk celebrity smackdowns here.

Re: review of another SE's design...

On Mar 21, 2008, at 4:26 PM, Andrew Kester, P.E. wrote:

> I guess I am asking for opinions, ideas, experiences of who has
> been through this before...
Take great pains to distinguish the things that are dangerous, things
that are merely wrong and things you might have done another way.

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

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

RE: review of another SE's design...

It is difficult to advise based on the limited information. But I will offer a few observations.

The report should focus on the technical aspects and avoid who should have done what. That may be an issue later. Write in the third person.

Try to be as dispassionate as possible. If this is a failure or short coming of some sort, there are some guidelines published by CASE. There are also some documents from ASTM: E 620, E 678, E 1658, E 1732 that may be helpful.

I would also recommend the book "Engineering Ethics - Concepts , Viewpoints, Cases and Codes", by the National Institute for Engineering Ethics at Texas Tech.

Regards,
Harold Sprague

From: akester@cfl.rr.com
To: seaint@seaint.org
Subject: review of another SE's design...
Date: Fri, 21 Mar 2008 17:26:13 -0400

Please email any comments or suggestions directly to me, as this is a weekend job...

I have been asked to review, from what I know, a respected long-time engineer in this area's job. It is a pretty big project, with some steel framing issues. The GC has hired us to investigate the steel that has been erected on-site (done), run some calcs on their steel sizes, and come up with some professional opinions in a report for a Monday afternoon as to what we think has occurred and how to fix it. They said they quote, "We do not care who is right or wrong, we have two parties pointing fingers, and we want your unbiased opinion.,"

It is a precarious position but at least I do not feel hamstrung. I want to be delicate, professional, and not hang another engineer out to dry.

I guess I am asking for opinions, ideas, experiences of who has been through this before...

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

How well do you know your celebrity gossip? Talk celebrity smackdowns here.

review of another SE's design...

Please email any comments or suggestions directly to me, as this is a weekend job...

It is a precarious position but at least I do not feel hamstrung. I want to be delicate, professional, and not hang another engineer out to dry.

I guess I am asking for opinions, ideas, experiences of who has been through this before...

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

Wind Load Utility

Hi All,

One of the tools I've been using with the new IBC wind loads is a tool
to interpolate the table values for various roof pitches, and values
of Lambda.

I use a much cleaner version of this to generate our load tables on
paper, but I tossed the code into a web page today, thinking others
might find it useful.

Check it out here:

http://www.examplecalcs.com/wind

Let me know if you're using it and I'll try to improve the output and
interface a bit. Suggestions are also welcome.

Thanks,

Chris

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

RE: Stainless Steel - answering my own question

With stainless, there is a lot of "it depends".

This site has a ton of info specifically for structural applications. They even have many structural shapes.
http://www.stainless-structurals.com/

They are allied with Georgia Tech.

Regards,
Harold Sprague

-----Original Message-----
From: Andrew Kester, P.E. [mailto:akester@cfl.rr.com]
Sent: Tuesday, March 18, 2008 8:05 PM
To: seaint
Subject: Stainless Steel - answering my own question

I still would like any heads ups and tables you may have, but I have found maybe too much info here:
Stainless Steel Info Center
http://www.ssina.com/index2.html

And what I understand is that SS is not governed by any codes in the US but it is in many other countries, and you should not use AISC but basic structural materials mechanics would be used.

From a web board, not from me, "One of the main differences is that carbon steel has a constant modulus of elasticity, while stainless has a varying modulus of elasticity based on the stresses in the steel"

Thanks,
Andrew

Test your Star IQ Play now!

RE: Structural Concrete subject to sub zero temp. conditions

The problem with freezing concrete that was cured prior to exposure is freeze thaw cycling as opposed to a steady state freeze. Any concrete that is cycling freezing and thawing can exhibit problems if it is not air entrained. What you are describing does not appear to be cycling. It is only unfrozen on rare occassions that the pump is out of service.

The integrity can be routinely checked by whacking the surface with a hammer. Sound concrete will have a definite ring. Freeze damaged concrete will be a thud. It is very distinctive. You can get an NDT test using impulse response. That will tell you if you have consistant concrete. Freeze damaged concrete will have a different response than sound concrete. But I would elect to just whack it with a hammer. If that shows damage then get the NDT.
http://olsonengineering.com

Concrete that is subject to freeze thaw cycling should be air entrained. You may have some level of air entrainment allready. It is often used to aid pumping. If you are unsure or want to be more definitive, a petrographic examination can determine the level of air entrainment.

Regards,
Harold Sprague

Date: Mon, 17 Mar 2008 22:20:52 +0300
From: lakshmana.nukala@gmail.com
To: seaint@seaint.org
Subject: Re: Structural Concrete subject to sub zero temp. conditions

Jerry & Daryl,

Thanks alot for responding to my mail, and for the offered info.

The foundation was cast and cured as per spec,(QC confirm the 28day strength), after commissioning of the plant, the Ice formation has started.  Actually It was hhardened concrete.  foundation foot print is about 1.5mX 0.8mX1.0mdeep, it supports a critical pump in LNG process plant. Hence the integrity of the foundation is big concern. This fdn is subject to ice formation about 2 years ago, and was continuously under same condition, expect for plant down time.

I have following questions,

1.   As this is a hardened concrete, and due to smaller size, can I ignore the effect of freezing of entrapped moisture?

2.  we have to leave it same condition due to operational aspect, how would i ensure the integrity of the foundation?

Any suggestion and references would be highly appreciated.

Best Regards

Lakshmana RK Nukala

On Mon, Mar 17, 2008 at 3:14 PM, Jerry Coombs <JCoombs@carollo.com> wrote:

When was it frozen? Did the uncured fndn freeze and at what point?   How big (all directions) is the footing? How critical is said footing? You can't place fresh concrete on a surface below freezing temp. Has to be thawed, warmed and thermally protected afterward.

>>> On 3/16/2008 at 1:24 PM, "Lakshmana Nukala" <lakshmana.nukala@gmail.com> wrote:

Dear All,

We are facing a situation, where the top 3 to 4 inch depth of top surface of a concrete foundation for pump is covered with ice formation.

Original design had never anticipated this situation, hence normal M35 grade concrete is used for this foundation. Surface temp of the concrete fdn found to be above -20 Degree C,

Any input or reference to to handle this situation would be great help for me.

Best Regards

Lakshmana RK Nukala

Test your Star IQ Play now!

RE: Seismic load on retaining wall

Arturo,

Yes there is an accepted method.

Go to the BSSC on line NEHRP Commentary Section 7.5 for the most definitive write up on this topic that includes yielding and nonyielding walls:
http://www.bssconline.org/NEHRP2003/comments/

The generally accepted approach in Section 7.5 was developed by Wood in 1973 with some modification by Whitman in 1991. The other aspects to consider are soil-structure interaction and the effect of saturated soils which is all in the write up.

This section was developed primarily by Maury Power and Chet Soydemir. It had an extensive peer review by the BSSC Provisions Update Committee (PUC) Technical Subcommittee 3 "Fndns. and Geotech Considerations" and the entire PUC. We "Nonbuilding Structures Technical Subcommittee" needed this write up in an effort to provide the superimposed loading for earth retaining structures.

Regards,
Harold Sprague

Date: Wed, 19 Mar 2008 09:52:29 -0500
To: seaint@seaint.org
From: amartine@udep.edu.pe
Subject: Seismic load on retaining wall

Is there any method used to estimate the seismic load on a retaining wall that is restrained for lateral movement? This wall is buried and is restrained by a concrete slab on top and a mat foundation at the bottom. I assume that under this condition, active pressures cannot develop, hence the Mononobe-Okabe method cannot be used. Am I right?. This wall is also below phreatic surface.
I will appreciate your input.

Arturo
Piura, Peru

How well do you know your celebrity gossip? Talk celebrity smackdowns here.

Re: Tekla Structures Training Centre at William Hare, Chennai, In

> From: G Vishwanath <gvshwnth@yahoo.com>

> I see no hope in the near future. It will take a few more years for a very
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This is the best news that I have heard all day! There is also a limit to
the off-shore talent pool! It means that the steadily increasing rates that
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career.

Regards
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--
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ph 905 639-9628
cell 905 802-3707
fax 905 639-3866
ad026@hwcn.org

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West Coasters!

I have a client that is looking to open a San Diego office. He is looking for a Professional Engineer with a CA Reg. that is working on the Construction Management side of the business to head up the office. He has an established client base and work in CA to support such a move. The job offers excellent benefits and a competitive salary. If you know of anyone that would fit the bill, or anyone that might be interested, I would appreciate the network help!

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Email: boyd@capobiancoassoc.com

Thursday, March 20, 2008

RE: Seismic load on retaining wall

While the M-O method gives a top-heavy triangular distribution, the
semi-rigid case using the 1.5 factor at the top, also results in a trapezoid
using 0.5 for the base pressure.

Thor A. Tandy P.Eng, MIStructE, Struct.Eng
Victoria, BC
Canada
vicpeng@telus.net

-----Original Message-----
From: arshad vali [mailto:arshadvali@yahoo.com]
Sent: Thursday, March 20, 2008 7:34 AM
To: seaint@seaint.org
Subject: Re: Seismic load on retaining wall

Hello Arturo,

You are correct about "the Mononobe-Okabe method
cannot be used."

I was reading the current AASHOT Code and in Section
A11.1.1.3 it states that

"The Mononobe-Okabe analysis assumes that the abutment
is free to latreally yield a sufficient amount to
mobolize peak soil strengths in the soil backfill. For
granular soils, peak strengths can be assumed to be
mobolized if deflections at the top of the wall are
about 0.5 percent of the abutment height. For
abutments restrained against lateral movement by
tiebacks or batter piles, lateral pressures induced by
inertia forces in the backfill will be greater than
those by a Mononobe-Okabe analysis. Simplified elastic
solutions presented by Wood (1973) for rigid
nonyielding walls also indicate that pressures are
greater than those given by Mononobe-Okabe. The use of
a factor of 1.5 in conjuction with peak ground
accelerations is suggested for design where doubt
exists that an abutment can yield sufficiently to
mobolize soil strenghts."

Hope this helps. If you need the actual sketch and
more information let me know.

Arshad Vali, SE
Los Angeles, CA.
--- Arturo Martinez <amartine@udep.edu.pe> wrote:

---------------------------------

Is there any method used to estimate the seismic load
on a retaining wallthat is restrained for lateral
movement? This wall is buried and isrestrained by a
concrete slab on top and a mat foundation at the
bottom. Iassume that under this condition, active
pressures cannot develop, hence theMononobe-Okabe
method cannot be used. Am I right?. This wall is also
belowphreatic surface.
I will appreciate your input.

Arturo
Piura,Peru

Questions to
seaint-ad@seaint.org. Remember, any email you * send
to the list is public domain and may be re-posted *
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Re: Seismic on restrained retaining walls

And the rule of thumb shall be to keep all of our retaining walls 11'-11" or less in height.

-gm

On Thu, Mar 20, 2008 at 9:12 AM, Hugh Brooks <hbap@aol.com> wrote:

The Mononobe-Okabe equations do not apply to restrained walls where activation movement is restricted.

For seismic lateral on restrained walls Retain Pro uses P = (soil density) x (k<sub h>) x (retained height)^2. Application is approx. 0.60 x (retained height). This is a slightly trapezoidal loading but with only slight error a uniform loading could be assumed. K<sub h> is the acceleration factor appropriate to the site.

See Kramer, Geotechnical Earthquake Engineering, Section 11.6.2.

Hugh Brooks, SE

Retain Pro Software

--
-gm

Seismic on restrained retaining walls

The Mononobe-Okabe equations do not apply to restrained walls where activation movement is restricted.

For seismic lateral on restrained walls Retain Pro uses P = (soil density) x (k<sub h>) x (retained height)^2. Application is approx. 0.60 x (retained height). This is a slightly trapezoidal loading but with only slight error a uniform loading could be assumed. K<sub h> is the acceleration factor appropriate to the site.

See Kramer, Geotechnical Earthquake Engineering, Section 11.6.2.

Hugh Brooks, SE

Retain Pro Software

Re: Seismic load on retaining wall

Hello Arturo,

You are correct about "the Mononobe-Okabe method
cannot be used."

I was reading the current AASHOT Code and in Section
A11.1.1.3 it states that

Hope this helps. If you need the actual sketch and
more information let me know.

Arshad Vali, SE
Los Angeles, CA.
--- Arturo Martinez <amartine@udep.edu.pe> wrote:

---------------------------------

Arturo
Piura,Peru

http://www.seaint.org/sealist1.asp**

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RE: Hand-held Calculator Recommended

Quote:

---------------------------------------------------------------------------------------------------

Off the subject a little, but in the same vein. I actually found my
old slide rule from college a few weeks ago. I swear I looked at it and
could not remember how to do a single thing on it. Nothing...no recollection
of how it worked whatsoever

-------------------------------------------------------

While on the subject of slide rules, I have half a dozen of these safely tucked away and which I bring out with a flourish and flaunt before the younger generation once in a while when we discuss what life used to be for us, the engineers of the previous generation.

I used to be quite an expert at slide rules. I was among the few who knew how to use the exponential functions on these slide rules. I had a Faber Castell slide rule with a 20" scale that yielded one more significant digit. These days, just for sentimental reasons, I sometimes take them out and look longingly at the neatly engraved markings and remenisce about the late sixties and early seventies when life without a slide rule was simply unimaginable.

When I shifted gears after 2001 and got involved in steel detailing for US fabricators, I got myself a Jobber 5 and played around with it for some time. I have now given it away to one of my staff.

Nowadays, I find no need for a hand held calculator. Most of my working hours are spent right in front of the monitor. Excel does whatever I want and I have programmed it to add and subtract in feet and inches and sixteeenths of an inch.

All the hard work on detailing is done by my office staff, who use Trig plus.
Autocad and X steel does all the complex stuff.

For me, who only needs to count the weeks or days before we ship the dwgs, the only hand held devices needed are my good old fingers. No fabricator gives me more than 10 weeks for any job and so my 10 fingers have so far been adequate. If I need to count larger than 10, I still have my toes. For larger numbers, I can still bank on what's left of my mental arithmetical abilities.

Regards
Vish

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Wednesday, March 19, 2008

RE: Stainless Steel

Christopher

Thanks for the information on stainless steel.

Though it was Andrew Kester who wrote:

> I still would like any heads ups and tables you may have, but I
> have found maybe too much info here:
> Stainless Steel Info Center

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

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Re: seaint Digest for 18 Mar 2008

> From: Christopher Wright <chrisw@skypoint.com>
> Subject: Re: Hand-held Calculator Recommended
> To: <seaint@seaint.org>
>
>> I need your recommendation for good hand-held calculator.
> I've used HP iron since the 70's, and they're the best made. Plenty

> I do most of my serious 'pencil and paper' calculations with Excel,
> but there's a boundary where I just need to have something for odds
> and ends--pythagorean theorem or composite section properties or a

> comes in handy at odd moments. And it fits in my shirt pocket--not
> even my Mac can do that yet.
>
> RPN i usually the deal-breaker for people who don't use HP machinery,
> but I think it's the greatest thing since premium rum if you need to
> do calculations with lots of intermediate results.

I had an HP 20S that wasn't RPN. Lost it last year. Probably left it on a
seat in an airport lounge. I miss the non-slip rubber feet and the feel of
the buttons. Most of the calculators I've seen are junk .. even the
replacement HP that I picked up at the local University store only had 3
memory registers. It's a good thing that HP is out of the calculator
business because they were going to blow their immense Good Will reserve,
otherwise.

I would have preferred to lose my aging (less than half as old) Titanium
laptop.

Regards
Paul
--
Paul Ransom, P.Eng.
ph 905 639-9628
cell 905 802-3707
fax 905 639-3866
ad026@hwcn.org

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Re: 26H8 joists

Drew,
From the 7th Edition Steel Manual, the 26H8 at 34' length has a total uniformly distributed allowable load of 394 plf. A live load of 370 plf will yield a deflection of L/360. The joist weighs 13 plf.

HTH,
Randall Collier, P.E.
Wink Companies, LLC
Baton Rouge, LA

Randy Collier

----- Original Message -----
From: Drew Morris <dmorris@bbfm.com>
To: SEAINT <seaint@seaint.org>
Cc: Samantha Spindler <sspindler@bbfm.com>
Sent: Wed Mar 19 18:13:12 2008
Subject: 26H8 joists

We have a job on an existing building. The roof framing plan shows a
series of 26H8 joists (L=33'-4"). This joist does not appear in the SJI
historical joist catalog. Does anyone have any idea what the TL/LL
allowable loads are?

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Re: 26H8 joists

26H8 joists

We have a job on an existing building. The roof framing plan shows a
series of 26H8 joists (L=33'-4"). This joist does not appear in the SJI
historical joist catalog. Does anyone have any idea what the TL/LL
allowable loads are?

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Re: Hand-held Calculator Recommended

On Mar 19, 2008, at 2:11 PM, Jason Christensen wrote:

> Man, I must be young, I was disappointed when the buttons on my HP
> 48G+
> stopped working and went to the HP 50G.
Probably true. Old age has some advantages, though. A month or so
after I bought my first 48G+ I left it inside a computer manual and
thought I'd lost it. In a panic, I bought another, then found the
first one. Now that I have 2 I figure I doubt if I'll ever be
needing another.

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RE: Hand-held Calculator Recommended

Off the subject a little, but in the same vein. I actually found my old
slide rule from college a few weeks ago. I swear I looked at it and could
not remember how to do a single thing on it. Nothing...no recollection of
how it worked whatsoever.

After about 5 minutes of fiddling around, I figured out multiplication, then
quickly put it back in its case and back in the box in the closet while
thinking to myself...."I took a senior year engineering final with THAT?
How'd I ever pass?"

-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com]
Sent: Wednesday, March 19, 2008 11:54 AM
To: seaint@seaint.org
Subject: Re: Hand-held Calculator Recommended

On Mar 19, 2008, at 1:44 PM, Donald Bruckman wrote:

> I'm a bit verklempt.
Tell me about it. I can't bring myself to toss out my deceased HP-67.
Or even the spare batteries I bought for it.

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RE: Hand-held Calculator Recommended

Man, I must be young, I was disappointed when the buttons on my HP 48G+
stopped working and went to the HP 50G.

Jason

-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com]
Sent: Wednesday, March 19, 2008 12:54 PM
To: seaint@seaint.org
Subject: Re: Hand-held Calculator Recommended

On Mar 19, 2008, at 1:44 PM, Donald Bruckman wrote:

> I'm a bit verklempt.
Tell me about it. I can't bring myself to toss out my deceased HP-67.
Or even the spare batteries I bought for it.

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

Re: Hand-held Calculator Recommended

On Mar 19, 2008, at 1:44 PM, Donald Bruckman wrote:

> I'm a bit verklempt.
Tell me about it. I can't bring myself to toss out my deceased HP-67.
Or even the spare batteries I bought for it.

RE: Hand-held Calculator Recommended

You folks are just re-opening old wounds and pouring salt on them.

Now, old memories, long suppressed, come rushing out at me. Little red LEDs, ENTER, memory stack, “x-y switch and divide”, HA !!…..Man…those were good times.

I had to stop what I was doing and go over to the cemetery to visit the grave of my old HP-41 and lay a wreath.

I don’t know if I can finish work today…

I’m a bit verklempt.

From: Larry Hauer [mailto:lrhauer@hotmail.com]
Sent: Wednesday, March 19, 2008 7:58 AM
To: seaint@seaint.org
Subject: RE: Hand-held Calculator Recommended

Helping your favorite cause is as easy as instant messaging. You IM, we give. Learn more.

Re: Hand-held Calculator Recommended

Gary L. Hodgson and Assoc. wrote:
>
> Christopher Wright wrote:
>> but I heard once that HP was out of the calculator business.
HP stills make scientific calculators. They recently came out with the
HP35s which is an updated version of the HP35 that came out in the early
70's. They originally cost $400, I got mine in 1975 for $300 (I thought
I got a great deal). I still have the HP35, I had to get a new battery
pack after too many recharges. At work I have a HP48G. When there was
a yet another rumor a few years ago that HP was getting out of the
calculator business, I bought 2 more 48Gs from Ebay. I don't like the
button locations for the new HPs. The funny thing is that the HP35 is
more than enough of a calculator for me (add, subtract, multiple,
cosine, etc.). If the calculations get complicated, I use a spreadsheet
instead of programming the calculator.

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Re: Hand-held Calculator Recommended

Amazing how many people are hanging on to old out-of-production calculators.

In anticipation of the death of my HP41, I found a keyboard macro thing (macro express)
and did some simple macros that operate on numbers in cells in excel and assigned them
to keys on my keyboard. That way I can put the keys where I'm used to them, i.e.
operations on the left and numbers on the right, like on a HP41 (which HP has not made
in the past 20 years or so). There is also an unlimited stack in excel, which you can see
and edit any step of.

MJ

Re: Stainless Steel

On Mar 18, 2008, at 11:37 PM, Conrad Harrison wrote:
> I still would like any heads ups and tables you may have, but I
> have found maybe too much info here:
> Stainless Steel Info Center
Back in the dear dead days when this country still took some pride in
manufacturing and steel production, INCO came out with a large number
of serious information on stainless. I don't know where they've
gotten to. They may be buried at Stainless Steel Info Center or the
Nickel Development Institute. These include ASTM STP 454 ''Structural
Stainless Steel -- Guidelines for Design' and 'A Design Guide to
Structural Stainless Steel' by Gilbert and Griffith. I couldn't find
them at the INCO site (now INCO-Vale) but you can try Google.

I also found this at the ASCE site: ASCE 8-02 Specifications for
Design of Cold-Formed Stainless Steel Structural Members.

The problem with cold formed stainless is that welding makes the
economics a bit tricky. The economy makes the raw material cost
pretty high, so using stiffened thin sections of strain hardened
materialyou can save material if you don't have to weld it or if
elastic buckling isn't an issue. Cold work increases the strength
greatly, but welding puts you back to the annealed state. Tooling
charges for formed sections will also eat you alive.

Stainless pipe is fairly common as are angles in small sizes. Larger
sizes are a bit trickier.
I got involved in one case where some poor soul specified a lifting
structure out of stainless rolled sections on the strength of a
magazine ad by an outfit who claimed they'd sell rolled shapes of all
kinds. Turned out that what they'd neglected to mention was that
they'd supply in mill quantities only with a 9 month delivery, but
not guaranteed. I expect the situation is worse today--trying to find
what you need will lead you on a merry chase around the world, and
you may end up with cast-off material that no one else will buy.

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RE: Hand-held Calculator Recommended

Since we are on the subject of "hand held" calculators, I have been using an HP 97 for about 30 years and wouldn't part with it because of the large key board, (it is really a desk top calculator of about 9" wide x 8" deep with a print out and card reader that stopped working about 20 years ago). Did HP ever make another calculator with a larger keyboard than the tiny hand held type, and, if so, what is the model number?

Thanks in advance,

Larry Hauer S.E.

> From: chrisw@skypoint.com
> Subject: Re: Hand-held Calculator Recommended
> Date: Tue, 18 Mar 2008 12:36:31 -0500
> To: seaint@seaint.org
>
>
> On Mar 18, 2008, at 12:13 PM, Bill Allen wrote:
>
> > The "deal breaker" for me is not being able to print calculations.
> > What good
> > are calculations if you can't publish them?
> I think that's what defines the boundary of usage--anything too
> complicated to write out by hand goes to Excel. If I need to decide
> on a scab plate thickness or go from electrical heat (watts and Kg
> and degC) to mechanical heat (HP, BTU, and weight) I use the HP and a
> couple of Post-it notes.
>
> Christopher Wright P.E. |"They couldn't hit an elephant at
> chrisw@skypoint.com | this distance" (last words of Gen.
> .......................................| John Sedgwick, Spotsylvania
> 1864)
> http://www.skypoint.com/~chrisw/
>
>
>
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> *
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Helping your favorite cause is as easy as instant messaging. You IM, we give. Learn more.

Seismic load on retaining wall

Is there any method used to estimate the seismic load on a retaining wall that is restrained for lateral movement? This wall is buried and is restrained by a concrete slab on top and a mat foundation at the bottom. I assume that under this condition, active pressures cannot develop, hence the Mononobe-Okabe method cannot be used. Am I right?. This wall is also below phreatic surface.
I will appreciate your input.

Arturo
Piura, Peru

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3-hour roof-ceiling assembly

Hi Jim:

Look at GA File No. FC 3140, or FC 3012. They are available at The Gypsum Association web site, www.gypsum.org These references are per the 2006 Manual.

Concrete fill on steel deck, steel joists and drywall ceiling. 3-hour protection.

Respectfully,

IDS Group, Inc.

Bob Freeman, AIA EIT

(949) 387-8500

RE: Hand-held Calculator Recommended

HP has a ‘new’ model out – the HP 35s is billed as a reincarnation of the old HP 35. It has both RPN and algebraic entry; you just set it either way (RPN for me). Functionally it’s along the lines of my old HP 32s. I think it was $55 or so. I was thrilled to find it.

Jim Carey

RE: Stainless Steel - answering my own question

Scott,

The 2006 IBC references SEI/ASCE 8-02.

The I-Codes are pretty good about updating standards. I believe every cycle ICC staff polls the various organizations listed in the referenced standards sections of the various codes, finds out which ones have been updated and republished, and generates one comprehensive code proposal with all the updates.

That just leaves new unreferenced standards or older referenced standards that are in the middle of their revision cycles. Those are the ones that wind up being considered separately (assuming someone remembers to bring them forward).

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

From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Wednesday, March 19, 2008 12:07 AM
To: seaint@seaint.org
Subject: RE: Stainless Steel - answering my own question

SEI/ASCE 8-02 - "Specification for the Design of Cold-Formed Stainless Steel Structural Members"

https://www.asce.org/bookstore/book.cfm?book=4286

2000 and 2003 IBC reference the older version: ASCE 8-90 (which I acquired many years ago when one of the architectural designers was in love with stainless steel and wanted to use structural stainless steel for our own office renovation...until the budget committee for the office renovation nipped that one in the bud...but I had already bought the book). I don't know what the 2006 IBC references as I have not gotten around to acquiring a 2006 IBC for myself as of yet.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Andrew Kester, P.E. [mailto:akester@cfl.rr.com]
Sent: Tuesday, March 18, 2008 8:05 PM
To: seaint
Subject: Stainless Steel - answering my own question

I still would like any heads ups and tables you may have, but I have found maybe too much info here:

Stainless Steel Info Center

http://www.ssina.com/index2.html

And what I understand is that SS is not governed by any codes in the US but it is in many other countries, and you should not use AISC but basic structural materials mechanics would be used.

From a web board, not from me, "One of the main differences is that carbon steel has a constant modulus of elasticity, while stainless has a varying modulus of elasticity based on the stresses in the steel"

Thanks,

Andrew