Structural Engineering: 2008-02-10

Saturday, February 16, 2008

Re: Soils Reports under CBC 1802.2

A slight correction. While cities have Sovereign Immunity the non-elected public servents do not have absolute immunity. Case law has established that if a goverment employee is clearly acting outside the laws and regulations regulating his activities he can be found personally liable. The case law includes at least one instance where a building inspector exceeded his authority. It is my understanding that the bar is set relatively high so that this would not kick in in most situations.

Never the less if a plan checker or building official were to require conformance with some requirement that could not be justified based on some law or regulation, and he had reason to believe that no such regulation existed then he could be found personally liable. This happens more often than you might guess.

The reason that there is not more litigation is that in most instances it is nor economical to sue the individual.

It does not appear that this situation would arrise when deciding whether a soils report is needed since the building official is allowed the choice and there is no requirement that he use common sense.

Mark Gilligan

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Re: Soils Reports under CBC 1802.2

Brian-

Sigh.. IANAL and , apparently neither are you. From an on-line legal
dictionary:
Malice aforethought is the the deliberate intent to cause death or great
bodily harm to another person before a person commits the crime. Malice
aforethought is an element that must be proved in the crime of first
degree murder. This description of the perpetrator's state of mind
basically means that he or she had an intent to inflict injury without
legal justification or excuse (legal justification included such
defenses as self-defense, while excuse includes mental illness and duress).

Malice aforethought is comprised of any one of the following three
elements: (1) an intent to kill; (2) an intent to inflict grievous
bodily injury; or (3) an intent to act in a manner that creates a plain
and strong likelihood that death or grievous harm will follow. Of these
three prongs of malice, the first two prongs require a specific intent
on the part of the defendant, measured subjectively, while the third
prong only requires a general intent, measured both subjectively and
objectively. Accordingly, malice aforethought may exist without an
actual intent to kill or do grievous bodily harm, if there is proof of
the "third prong" of malice. This simply means that the perpetrator knew
of circumstances that a reasonably prudent person would have known
created a plain and strong likelihood of death or grievous bodily harm
resulting from the perpetrator's act. The law can infer malice from
circumstantial evidence, such as from the intentional use of a deadly
weapon.

How any reasonable person could get from that, to an unwillingness to
make simple decision about probable soil conditions, is beyond my
understanding. Having participated in many conferences with plaintiff
attorneys & court appointed Special Masters I am fairly familiar with
the concept of Sovereign Immunity. City's and Code Officials are never
targets in defect litigation suits even when they make egregious errors
in Plan Check &/or inspection. I suppose if you were taking bribes there
might be liability, but not from the ordinary exercise of judgment in
your duties.
Chuck Utzman
> ____________________
> From: Brian Gerving [mailto:bgerving@ci.eureka.ca.gov]
> Sent: Friday, February 15, 2008 2:01 PM
> To: seaint@seaint.org
> Subject: RE: Soils Reports under CBC 1802.2
>
> Why the indecision? Building officials certainly do have personal liability
> if malice or forethought is involved in a given decision. Discussing issues
> like this ad nauseam, which believe me, building officials around the state
> have done, definitely qualifies as forethought.
>
> Regarding the ability of building officials to waive soils reports, please
> read the text of the exception to Section 1802.2:
>
> "The building official need not require a foundation or soils investigation
> where satisfactory data from adjacent areas is available that demonstrates
> an investigation is not necessary for any of the conditions in Sections
> 1802.2.1 through 1802.2.6."
>
> Note that the exception does not apply to Section 1802.2.7, which is what
> triggers soils reports for structures assigned to SDCs D, E, and F.
>
> Brian
>
>

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RE: Soils Reports under CBC 1802.2

Hi Brian;
It's still up to the local Building Official to determine where the
potential for "liquefaction and soil strength loss" detailed in CBC Section
1802.2.7.2 would generate the requirement for a Soils Report. The potential
for "liquefaction and soil strength loss" in our Mother Lode area of
California is VERY low therefore BO's should be allowed to waive the
requirement for a Soils Report. Outside of our 0.4 Ss area, we get SDC D
for most of the non-residential buildings. It's ludicrous for Building
Departments to require a Soils Report just because of that section of the
Code when there is no chance for "liquefaction and soil strength loss" on a
project. Where is the out? We have one jurisdiction saying they will not
generally require a Soils Report and three saying "We're not sure yet"....
This portion of the code is very poorly written and I hope it will
be revised in the next cycle.

Terry Weatherby
Weatherby-Reynolds-Fritson
Engineering and Design
Jackson, CA
________________________________________
From: Brian Gerving [mailto:bgerving@ci.eureka.ca.gov]
Sent: Friday, February 15, 2008 2:01 PM
To: seaint@seaint.org
Subject: RE: Soils Reports under CBC 1802.2

Why the indecision? Building officials certainly do have personal liability
if malice or forethought is involved in a given decision. Discussing issues
like this ad nauseam, which believe me, building officials around the state
have done, definitely qualifies as forethought.

Regarding the ability of building officials to waive soils reports, please
read the text of the exception to Section 1802.2:

"The building official need not require a foundation or soils investigation
where satisfactory data from adjacent areas is available that demonstrates
an investigation is not necessary for any of the conditions in Sections
1802.2.1 through 1802.2.6."

Note that the exception does not apply to Section 1802.2.7, which is what
triggers soils reports for structures assigned to SDCs D, E, and F.

Brian

________________________________________
From: Rhkratzse@aol.com [mailto:Rhkratzse@aol.com]
Sent: Friday, February 15, 2008 12:30 PM
To: chuckuc@pacbell.net; seaint@seaint.org
Subject: Re: Soils Reports under CBC 1802.2

In a message dated 2/15/08 12:23:24 PM, chuckuc@pacbell.net writes:
Brian
I have one local CBO who doing the same (& another who is can't make up
his mind).
Chuck Utzman

Why the indecision? From this side of the fence -- the practicing engineer
side -- the BO's are in the enviable position of having *all* the power and
of being able to make decisions for the good of society as they see it,
WITHOUT having to worry about being sued. Not a bad position to be in; I
wish I were in the same position and could actually design what I felt was
the best structure for the situation without worrying about having
*everyone* second-guessing me because I dropped a 4th decimal place in some
arcane wind calculation or missed some obscure code requirement that's
hanging on from many decades ago but just never got rooted out.

I'm dead serious.

End of vent.

Ralph

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Re: Moving Walkway Seismic Restraint

This is also my experience in dealing with ME's and Building Code issues.
Breaking out dead and live loads for reactions is sometimes foreign to
manufacturers. The issues usually boil down to mistaken assumptions about
scope and common practice (e.g. who is responsible for the connections, what
level of seismic event must the device withstand and remain operable).
Arrange to talk to the manufacturer's designer or engineer rather than
through the letter writing chain via sales people and project coordinators.
Send the designer a copy of the Building Code clauses about anchorages of
non-structural elements.

The mechanical code only establishes the minimum load and performance
conditions that their product must achieve. However, your structure has to
resist the effects that are developed according to the Building Code
procedure and applied at the supports. The response and performance
expectations may be wildly different.

The biggest barrier that you will probably have is getting people to look
past the notion that you are asking the manufacturer to redesign their
product to suit your Building Code forces. That's not required. Ultimately,
you may find that their product will behave in a complex, non-linear manner
and have no ability to transfer the maximum Building Code effects to the
anchors (e.g the assembly will fail in wildly unpredictable ways and bang
against all manner of obstructions, killing and smashing everything in its
path ... but it meets ASME). ;)

After that, maybe there really is an issue that needs to be resolved by the
project design team.

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

> From: "Chris Slater" <chris@jdwylieengineering.com>
> To: seaint@seaint.org
> Subject: Re: Moving Walkway Seismic Restraint
>
> Daniel,
>
> I have a Master's Degree in Mechanical Engineering, and I can tell you
> that I never learned about lateral forces until I started working in
> the structural engineering field.
>
> My guess is that they just don't understand what it is you're talking
> about. It seems to me that the highest priority is just being sure
> that the project gets designed safely - and I think the way to make
> that happen is to educate the manufacturer on seismic design and then
> work with them to figure out what type of anchorage is needed to make
> it safe in an earthquake. Ideally, they'll come back to you to tell
> them what needs to be done.
>
> Chris

> On Feb 12, 2008 4:34 PM, Daniel Popp <drp181@yahoo.com> wrote:
>>
>> An update: the walkway manufacturer has provided a "total horizontal force"

>> still have two problems: the difference in expected force level and the lack
>> of a load path.

>> Speaking of which: if anyone has access to the ASME A17.1 code (2000
>> version or newer), I would appreciate an excerpt from the seismic force
>> section (8.5, I believe).
>>
>> Daniel

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Re: Fw: PLEASE READ NOW - Real virus [OT: not really about viruses]

Re: return receipt receipt virus

I set Outlook to auto-decline all receipt requests. It's nobody's damned
business WHEN or IF I read their messages. Just because Outlook displayed
the message in the viewer doesn't mean that I consumed the content or that I
wish to acknowledge my actions.

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

> From: "David Fisher" <dfisher@fpse.com>

> No kidding, Ralph.
>
> I like the return receipt receipt concept.
>
> Its funny, in 99% of cases, when I get the "Return receipt requested"
> message in Outlook, I decline.
>
> So controlling.
>
> David L. Fisher SE PE

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RE: Wind Calcs_ Interpolation of Cp Value at flat roof

The wind still blows on Saturday! <grin>

Back to the salt mines for ya! ;-)

Scott

Adrian, MI

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill@cableone.net]
Sent: Saturday, February 16, 2008 11:54 AM
To: seaint@seaint.org
Subject: Re: Wind Calcs_ Interpolation of Cp Value at flat roof

Scott,

Thanks, I was kind of hoping for the adjustment, but really didn't think it was there for the same reasons you gave. Saturday doing wind calcs. Not a good time.

Joe

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

From: Scott Maxwell

To: seaint@seaint.org

Sent: Saturday, February 16, 2008 9:49 AM

Subject: RE: Wind Calcs_ Interpolation of Cp Value at flat roof

I would say "yes" for the interpolation between -0.9 and -1.3, but "no" to the use of the Reduction Factors. Since the double asterisk is for only the h/L >= 1.0 value, I interpret that to mean that it only applies if you are at an h/L greater then 1.0. Since you are between h/L of 0.5 and 1.0, I would say it does not apply.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill@cableone.net]
Sent: Saturday, February 16, 2008 11:42 AM
To: seaint@seaint.org
Subject: Wind Calcs_ Interpolation of Cp Value at flat roof

I am looking within the table for Cp for the "All Heights" method (figure 6-6). I have a structure with a flat roof and an h/L between .5 and 1.0. For Cp values for horiz. dist. 0 to h/2 I'm pretty sure you can interpolate between -.9 and -1.3. Tell me if I'm incorrect there, but also, can you use the "Reduction Factors" for the interpolated Cp?

Thanks,

Joe Grill

Re: Wind Calcs_ Interpolation of Cp Value at flat roof

Scott,

Thanks, I was kind of hoping for the adjustment, but really didn't think it was there for the same reasons you gave. Saturday doing wind calcs. Not a good time.

Joe

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

From: Scott Maxwell

To: seaint@seaint.org

Sent: Saturday, February 16, 2008 9:49 AM

Subject: RE: Wind Calcs_ Interpolation of Cp Value at flat roof

I would say "yes" for the interpolation between -0.9 and -1.3, but "no" to the use of the Reduction Factors. Since the double asterisk is for only the h/L >= 1.0 value, I interpret that to mean that it only applies if you are at an h/L greater then 1.0. Since you are between h/L of 0.5 and 1.0, I would say it does not apply.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill@cableone.net]
Sent: Saturday, February 16, 2008 11:42 AM
To: seaint@seaint.org
Subject: Wind Calcs_ Interpolation of Cp Value at flat roof

I am looking within the table for Cp for the "All Heights" method (figure 6-6). I have a structure with a flat roof and an h/L between .5 and 1.0. For Cp values for horiz. dist. 0 to h/2 I'm pretty sure you can interpolate between -.9 and -1.3. Tell me if I'm incorrect there, but also, can you use the "Reduction Factors" for the interpolated Cp?

Thanks,

Joe Grill

RE: Wind Calcs_ Interpolation of Cp Value at flat roof

I would say "yes" for the interpolation between -0.9 and -1.3, but "no" to the use of the Reduction Factors. Since the double asterisk is for only the h/L >= 1.0 value, I interpret that to mean that it only applies if you are at an h/L greater then 1.0. Since you are between h/L of 0.5 and 1.0, I would say it does not apply.

Regards,

Scott

Adrian, MI

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill@cableone.net]
Sent: Saturday, February 16, 2008 11:42 AM
To: seaint@seaint.org
Subject: Wind Calcs_ Interpolation of Cp Value at flat roof

I am looking within the table for Cp for the "All Heights" method (figure 6-6). I have a structure with a flat roof and an h/L between .5 and 1.0. For Cp values for horiz. dist. 0 to h/2 I'm pretty sure you can interpolate between -.9 and -1.3. Tell me if I'm incorrect there, but also, can you use the "Reduction Factors" for the interpolated Cp?

Thanks,

Joe Grill

Wind Calcs_ Interpolation of Cp Value at flat roof

I am looking within the table for Cp for the "All Heights" method (figure 6-6). I have a structure with a flat roof and an h/L between .5 and 1.0. For Cp values for horiz. dist. 0 to h/2 I'm pretty sure you can interpolate between -.9 and -1.3. Tell me if I'm incorrect there, but also, can you use the "Reduction Factors" for the interpolated Cp?

Thanks,

Joe Grill

RE: Chain Link Fence Backstop

Assuming that David is doing something on his "home turf", I kind of doubt
ice and snow will be huge concern. Not too much of that down in Florida!
;-)

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Gary L. Hodgson and Assoc. [mailto:ghodgson@bellnet.ca]
Sent: Saturday, February 16, 2008 8:34 AM
To: seaint@seaint.org
Subject: Re: Chain Link Fence Backstop

Allow for debris (newspapers etc getting caught the fence) and up here
ice and snow on it.
Gary

M. David Finley, P.E., P.A. wrote:
> I'm designing a baseball backstop for a city recreation park in
> Florida. The Owner wants a 28' foot high backstop - 18' of chain link
> fence topped with 10' of netting. I'll check for adequate wind load
> strength as an open sign using ASCE-7. And I'm planning on checking
> it for a railing horizontal load to allow for people leaning against it.
>
> Any words of wisdom from others who have done one of these?
>
> David Finley
>
>

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Re: IBC 2007 Wind calcs.

Thanks, Scott.
I remember having to deal with ASCE seismic requirements once and they
might as well have been in Greek or Chinese.
Gary

Scott Maxwell wrote:
> Gary,
>
> The issue is that what was in the UBC for wind was rather straight forward.
> It was simple calculation of P = Ce*Cq*qs*Iw, where:
>
> P is the design pressure
> Ce is a factor to take into account exposure type (i.e. rural with no
> obstructions, urban with similar obstructions, etc), gust effects and
> height
> Cq is a pressure cofficient for the structure or the portion of the
> structure under cosideration qs is a basic wind pressure that is a function
> of the wind speed (basically 0.00256 * (wind velocity)^2) Iw is an
> importance factor
>
> It was a very simple, straight forward process.
>
> ASCE 7 has always been a little more complicated historically. It has been
> rather similar for MWFRS pressures, but had a separate method for Components
> & Cladding (C&C) that took into accound the tributary area of the element.
> Over all, that has been a major difference between the UBC implementation
> and ASCE 7...effects of the "wind sail size" for what ever element that is
> under consideration. Personally, this is where I think the UBC has always
> been weak. Generally, speaking, however, the older ASCE 7 versions were
> only a little more complex than what was in the UBC (it tended to look a lot
> more complex due to the nomenclature...the "variables" appear more "complex"
> or "bigger", but in reality it is not that much differnet).
>
> The more current versions of ASCE 7 have mucked things up quite a bit.
> There is now a Kzt factor which takes into account topographic effects (i.e.
> hills, enscarpments, etc and how they speed up wind, etc). They have added
> in a method for flexible buildings which literally feels like rocket science
> to me. They have move to more variances in pressures for MWFRS over
> different part of the structure surface. In general, the methods have
> gotten more complex and require more calculations and thought...more
> variables in the formula...more coefficients to look up in a wider array of
> tables and figures. Not to mention the organization of ASCE 7 leaves a lot
> to be desired at times.
>
> Regards,
>
> Scott
> Adrian, MI
>
> -----Original Message-----
> From: Gary L. Hodgson and Assoc. [mailto:ghodgson@bellnet.ca]
> Sent: Friday, February 15, 2008 8:03 AM
> To: seaint@seaint.org
> Subject: Re: IBC 2007 Wind calcs.
>
>
> List,
> I have been sort of following this wind discussion and wonder if you
> could enlighten me. Since we don't use your codes, I am wondering what
> it is about these new ASCE provisions that has got all your knickers in
> a knot. Can you send an example or copy of the particular section. If
> it is too big, don't bother. I am just curious.
> Gary
>
>
>
>
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> *
> * This email was sent to you via Structural Engineers
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Re: Chain Link Fence Backstop

Allow for debris (newspapers etc getting caught the fence) and up here
ice and snow on it.
Gary

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Friday, February 15, 2008

RE: Alternate Wind Provision

The 2007 CBC/ ASCE 7-05 wind provisions which are causing many of us in CA so much trouble are apparently complex enough that the Division of State Architect (which controls all school and State building plans) has prepared an 8 page directive to help us interpret the 50 page ASCE 7-05 document.
The Div. of State Architect document presents an "Alternative Method"
which is very helpful.

Stan Scholl, P.E.
Laguna Beach, CA

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Re: wind codes...

Yes, we must submit calcs. and I am on my 2nd try to even get submittal accepted to check- on a 2nd story house addition.

Stan Scholl, P.E.
Laguna Beach, CA
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Re: Seismic Design Example

Sharon

Vertical component of earthquake. .2Sds...... .2x1.19x3= .714D

In a message dated 2/15/2008 3:37:51 P.M. Pacific Standard Time, ECVAl3@aol.com writes:

For those of you that have and understand the "2006 IBC Structural/Seismic Design Manual Vol.2" I have a question.

On page 32 to determine the Anchorage at A on a perforated shear wall:

Going from the formula (0.9-0.2*SDS)*D + Wo*QE

Wo = 3.0, SDS = 1.19

they suddenly go to the formula (0.9-0.2*SDS)*D + Wo*E

Putting the numerical values in they get (0.9-0.2*1.19)*D + 0.66*D

My question is, how did they get 0.66*D from Wo*QE or Wo*E ?

Can anyone shed some light on this for me?

Thank you,

S.Macie

Joe Venuti
Johnson & Nielsen Associates
Palm Springs, CA

The year's hottest artists on the red carpet at the Grammy Awards. AOL Music takes you there.

RE: SOG/fibers cont...

You might want to consider crusher fines over the vapor barrier in lieu of the sand. It compacts better and provides a good surface on which to set the dobies for the rebar support.

Regards,
Harold Sprague

Date: Thu, 14 Feb 2008 15:06:16 -0800
From: bruckmandesign@verizon.net
Subject: RE: SOG/fibers cont...
To: seaint@seaint.org

Further expanding on the SOG discussion, I am thinking of moving toward altering my SOG construction technique and specs/drawings to eliminate the "aggregate sub-base" in favor of using regular compacted ASTM Class 2 roadbed and then a topping of sand over the moisture barrier. I've been very unhappy with the mess made by rod-busters to the sub-base when rebar is spec'd over the standard rock/visqueen/sand arrangement. It doesn't compact well and by the time the rebar is down, with all the footprints and stuff, you'd hardly know the sub-base was ever rolled flat to start with.

I suppose this would be a soil engineer's call, but I'd think the structural engineer would like the idea and its certainly easier to construct.

From: Jerry Coombs [mailto:JCoombs@carollo.com]
Sent: Thursday, February 14, 2008 12:22 PM
To: seaint
Subject: Re: SOG/fibers cont...

Some good points. It's not structural. No reason it (and any other simple non-struct SOG) can't be done by the Arch. No magic to it. simple cost/ /risk/ performance issues.

In areas where I've done some work, contr'r have been very resistant because they can use a laser screed. Can't do that w/ most WWF or reinf slabs. Fibers apparently worked well, but haven't checked recently.

>>> On 2/14/2008 at 1:58 PM, "Andrew Kester, P.E." <akester@cfl.rr.com> wrote:

To expand slightly on this discussion, at my last two companies and my own, we have for some time now been using poly fibers as a replacement for WWR which is up to the GC per our general notes. It has been 1.5lb/cy of 1.5" poly fibers, then it grew to 3.5lb/cy, which may be too much I suppose. But in the end I am now doubting poly fibers effectiveness whatsoever in all but the most microscopic cracks. These are on non-structural SOG, nothing industrial or forklift traffic, etc.

We show CJs on our foundation plan at wall returns, changes in slab direction, columns, etc. and not more than 12'-0" o.c. We take the time to detail these, not sure if they do it.... Also using a Soffcut saw within 4-6 hrs of slab pour or as soon as the concrete is hard enough to walk on, at 1/3 depth of the slab.

Now we rarely get paid on our smaller jobs to go do site visits to review the slabs, so I don't know how they are all performing. I just do not know of any issues we have had or my former companies doing SOG this way in FL, in other words, no comments or phone calls. I know to take all of this with a grain of salt, as the slabs may crack and people just except it. I do not know if is due to our very sandy soil or our warm and humid client, etc. Expansive soils can happen in certain areas but are rather limited.

I agree with Harold that all concrete cracks, especially SOG, and am surprised if I don't see it... I would like to specify WWR or even #3 bars each way, but no GC or client will likely go willingly along for the ride. I am thinking of adding language on our General Notes that states as it is a non-structural component, we will specify the use of steel reinforcement to LIMIT cracks in the slab. If they want to eliminate it, we will send them a one paragraph form to sign and send back that says they did not use steel at their discretion and they will hold us harmless if the slab's serviceablity is undesireable. Although, I am in no way offering a warranty of any SOG.... I wish we did not even have to spec a non structural SOG, we just don't care. Basically, if they have tile they don't want it cracking and don't want bumps in their carpet.

Any thoughts?

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

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Seismic Design Example

For those of you that have and understand the "2006 IBC Structural/Seismic Design Manual Vol.2" I have a question.

On page 32 to determine the Anchorage at A on a perforated shear wall:

Going from the formula (0.9-0.2*SDS)*D + Wo*QE

Wo = 3.0, SDS = 1.19

they suddenly go to the formula (0.9-0.2*SDS)*D + Wo*E

Putting the numerical values in they get (0.9-0.2*1.19)*D + 0.66*D

My question is, how did they get 0.66*D from Wo*QE or Wo*E ?

Can anyone shed some light on this for me?

Thank you,

S.Macie

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Re: wind codes...

Andrew

I agree with you and Paul But I find nothing wrong with method 1 on most projects 2 story or less. However we here in CA do submit stamped plans & calculations on every project no matter how small.

Joe Venuti

n a message dated 2/15/2008 1:26:58 P.M. Pacific Standard Time, akester@cfl.rr.com writes:

In FL we have no seismic or snow so we know what governs lateral wind loads, up to V=150mph. But if your building is a "simple diaphragm", enclosed, and under 60ft (95% of our projects), there are pages of simplifed tables from 90mph-150mph. The Florida Building Code is available online for free, if you guys in other parts of the country want to "double-check" your other methods of calculating pressures. Evidently, nobody seems to think this simplified method is either to conservative or too liberal for useage for the most common types of structures, which is just fine by me.

Do you guys in CA or out west have to submit calcs? Who knows what methods you are using as long as they are reasonable and you are getting "correct" results, if not a little overly conservative. I am just wondering what would prevent you from using an older method that you find reliable and easier to use. The only time in FL where we have to submit calcs for other people to review is on government work.... Otherwise, the plan reviewers don't really check much from what I can tell but the most basic stuff, the leave it up to the engineer to have done their job properly. Me likey this method!

I completely agree with Paul. For most examples he gave, and I recently read 85% of new construction in the US is 3 story and less, a simplifed version would work just fine. Who cares about 2psf? Who is this accurate in their calcs? You guys never round to the nearest KIP? If you size a connection for uplift do you make sure you have a few extra pounds? Uplift connections from columns to concrete maybe a an extra KIP? What about when deflection/drift controls and not strength? What about the strength and reduction factors applied during steel and concrete design, adding additional safety? And many products like Simpson uplift connections, epoxy and expansion bolts, screws, etc. have an ultimate strength of 4x the allowable...

My point is that we are not designing things to this degree of accuracy for the most part. There is no need to be that accurate, both for design simplification and construciton simplification. The cost savings for a few bucks of steel and concrete here and there are minute compared to the costs of MEP, glass curtain walls, fancy finishes, etc, all of which offer no additional safety during a wind event (minus the glass)....

Making things that complicated just may create errors. I agree with Paul this time should be spend coordinating with the ARCH and MEP drawings, properly designing cut sections, details, connections, etc. In my hurricane forensics and my wind design experience, it is the smallest elements that are the Achiles Heel of a building. Plywood sheathing pulling off a roof truss, a roof truss connection failing due to improper nailing or being improperly sized, roof mtl deck peeling back, etc. It is not masonry walls failing in shear. It would rarely be a structural moment frame failing at the welds, or a braced frame buckling, or a improperly sized concrete footing pulled out of the ground as a frame or column goes tumbling down the road....

Just thanking my engineering gods I do not work with seismic on top of wind, or snow.... Just lots of wind and sandy soil that gets you 2000psf. Not too bad.

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

Joe Venuti
Johnson & Nielsen Associates
Palm Springs, CA

The year's hottest artists on the red carpet at the Grammy Awards. AOL Music takes you there.

Re: Soils Reports under CBC 1802.2

I'm no lawyer, but I seriously doubt that merely thinking about something (AKA "forethought") is enough to trigger "personal liability." Now malice is another thing -- if you just happen to do something that favors your brother's landholdings I suspect that you might land on the front page of your local paper, and possibly even in court. But just allowing that 1000 psf has worked in your county for the last century (*if* it has), and thus not requiring a soil report for a new house, would hardly amount to malice, IMHO.

Ralph

In a message dated 2/15/08 2:02:02 PM, bgerving@ci.eureka.ca.gov writes:

Why the indecision? Building officials certainly do have personal liability if malice or forethought is involved in a given decision. Discussing issues like this ad nauseam, which believe me, building officials around the state have done, definitely qualifies as forethought.

Regarding the ability of building officials to waive soils reports, please read the text of the exception to Section 1802.2:

"The building official need not require a foundation or soils investigation where satisfactory data from adjacent areas is available that demonstrates an investigation is not necessary for any of the conditions in Sections 1802.2.1 through 1802.2.6."

Note that the exception does not apply to Section 1802.2.7, which is what triggers soils reports for structures assigned to SDCs D, E, and F.

Brian

From: Rhkratzse@aol.com [mailto:Rhkratzse@aol.com]
Sent: Friday, February 15, 2008 12:30 PM
To: chuckuc@pacbell.net; seaint@seaint.org
Subject: Re: Soils Reports under CBC 1802.2

In a message dated 2/15/08 12:23:24 PM, chuckuc@pacbell.net writes:

Brian
I have one local CBO who doing the same (& another who is can't make up
his mind).
Chuck Utzman

Why the indecision? From this side of the fence -- the practicing engineer side -- the BO's are in the enviable position of having *all* the power and of being able to make decisions for the good of society as they see it, WITHOUT having to worry about being sued. Not a bad position to be in; I wish I were in the same position and could actually design what I felt was the best structure for the situation without worrying about having *everyone* second-guessing me because I dropped a 4th decimal place in some arcane wind calculation or missed some obscure code requirement that's hanging on from many decades ago but just never got rooted out.

I'm dead serious.

End of vent.

Ralph

**************
The year's hottest artists on the red carpet at the Grammy Awards. Go to AOL Music.
(http://music.aol.com/grammys?NCID=aolcmp00300000002565)

RE: Soils Reports under CBC 1802.2

Why the indecision? Building officials certainly do have personal liability if malice or forethought is involved in a given decision. Discussing issues like this ad nauseam, which believe me, building officials around the state have done, definitely qualifies as forethought.

Regarding the ability of building officials to waive soils reports, please read the text of the exception to Section 1802.2:

“The building official need not require a foundation or soils investigation where satisfactory data from adjacent areas is available that demonstrates an investigation is not necessary for any of the conditions in Sections 1802.2.1 through 1802.2.6.”

Note that the exception does not apply to Section 1802.2.7, which is what triggers soils reports for structures assigned to SDCs D, E, and F.

Brian

From: Rhkratzse@aol.com [mailto:Rhkratzse@aol.com]
Sent: Friday, February 15, 2008 12:30 PM
To: chuckuc@pacbell.net; seaint@seaint.org
Subject: Re: Soils Reports under CBC 1802.2

In a message dated 2/15/08 12:23:24 PM, chuckuc@pacbell.net writes:

Brian
I have one local CBO who doing the same (& another who is can't make up
his mind).
Chuck Utzman

Why the indecision? From this side of the fence -- the practicing engineer side -- the BO's are in the enviable position of having *all* the power and of being able to make decisions for the good of society as they see it, WITHOUT having to worry about being sued. Not a bad position to be in; I wish I were in the same position and could actually design what I felt was the best structure for the situation without worrying about having *everyone* second-guessing me because I dropped a 4th decimal place in some arcane wind calculation or missed some obscure code requirement that's hanging on from many decades ago but just never got rooted out.

I'm dead serious.

End of vent.

Ralph

**************
The year's hottest artists on the red carpet at the Grammy Awards. Go to AOL Music.
(http://music.aol.com/grammys?NCID=aolcmp00300000002565)

Re: Alternate Wind Provision

At least you guys in the old Zone 0 should get a whole bunch of retrofit work out of it. We old UBC wind method guys get no new work out of the "new" wind provisions!

Jusy out of curiosity, what affects on existing construction has going with the NEHRP-based IBC code family had on new construction and rehabilitation work? Do occupancy changes or projects spending a certain amount trigger seismic upgrades now?

-Ben Maxwell

Jerry Coombs <JCoombs@carollo.com> wrote:

It is, however, quite similar to the arguement about seismic efforts now required in TX and other Category A and B areas.

>>> On 2/15/2008 at 11:38 AM, <Rhkratzse@aol.com> wrote:

James,

Thank you for your Information Bulletin.

I am *amazed* that the "stealth" wind load provisions managed to become law without a hint of their impact on the practicing Structural Engineer, but once they became effective it appears to *nobody* really understands them, they require enormously greater effort for minuscule, if any, improvement in the end result.

How did this happen?

Ralph Hueston Kratz, S.E.
Richmond CA USA

In a message dated 2/14/08 11:02:08 PM, sylai@sbcglobal.net writes:

Information bulletin:

For those who are interested on wind design procedure, we have two parallel versions of proposed code changes (items S84 and S85) submitted to ICC, and will be heard by the ICC Structural Committee in the Code Development Hearing at Palm Springs later this month. Both versions have been development by the Tri State Wind committee with delegates appointed by their respective structural engineers association from California, Oregon and Washington. The alternate design procedure conforms to ASCE 7 Chapter 6 Method 2, but greatly simplified by tabulating net pressure coefficients for MWRFas well as for components and claddings. The main difference between the two versions is the format of the net pressure coefficient table very much similar to UBC 1997 in format.

The proposal from SEAOC Wind Ad Hoc committee is now incorporated and adopted as an Interpretation of regulation under the California Division of State Architects which has juridiction over K-12 and community colleges. The provision is call IR 16-7. Those interested may view it under:

http://www.documents.dgs.ca.gov/dsa/pubs/IR_Manual_updated_12-19-07.pdf

James Lai, F.SEAOC
Chair, SEAOC Building Code Committee

**************
The year's hottest artists on the red carpet at the Grammy Awards. Go to AOL Music.
(http://music.aol.com/grammys?NCID=aolcmp00300000002565)

Benjamin H. Maxwell, S.E.

Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.

wind codes...

In FL we have no seismic or snow so we know what governs lateral wind loads, up to V=150mph. But if your building is a "simple diaphragm", enclosed, and under 60ft (95% of our projects), there are pages of simplifed tables from 90mph-150mph. The Florida Building Code is available online for free, if you guys in other parts of the country want to "double-check" your other methods of calculating pressures. Evidently, nobody seems to think this simplified method is either to conservative or too liberal for useage for the most common types of structures, which is just fine by me.

Do you guys in CA or out west have to submit calcs? Who knows what methods you are using as long as they are reasonable and you are getting "correct" results, if not a little overly conservative. I am just wondering what would prevent you from using an older method that you find reliable and easier to use. The only time in FL where we have to submit calcs for other people to review is on government work.... Otherwise, the plan reviewers don't really check much from what I can tell but the most basic stuff, the leave it up to the engineer to have done their job properly. Me likey this method!

I completely agree with Paul. For most examples he gave, and I recently read 85% of new construction in the US is 3 story and less, a simplifed version would work just fine. Who cares about 2psf? Who is this accurate in their calcs? You guys never round to the nearest KIP? If you size a connection for uplift do you make sure you have a few extra pounds? Uplift connections from columns to concrete maybe a an extra KIP? What about when deflection/drift controls and not strength? What about the strength and reduction factors applied during steel and concrete design, adding additional safety? And many products like Simpson uplift connections, epoxy and expansion bolts, screws, etc. have an ultimate strength of 4x the allowable...

My point is that we are not designing things to this degree of accuracy for the most part. There is no need to be that accurate, both for design simplification and construciton simplification. The cost savings for a few bucks of steel and concrete here and there are minute compared to the costs of MEP, glass curtain walls, fancy finishes, etc, all of which offer no additional safety during a wind event (minus the glass)....

Making things that complicated just may create errors. I agree with Paul this time should be spend coordinating with the ARCH and MEP drawings, properly designing cut sections, details, connections, etc. In my hurricane forensics and my wind design experience, it is the smallest elements that are the Achiles Heel of a building. Plywood sheathing pulling off a roof truss, a roof truss connection failing due to improper nailing or being improperly sized, roof mtl deck peeling back, etc. It is not masonry walls failing in shear. It would rarely be a structural moment frame failing at the welds, or a braced frame buckling, or a improperly sized concrete footing pulled out of the ground as a frame or column goes tumbling down the road....

Just thanking my engineering gods I do not work with seismic on top of wind, or snow.... Just lots of wind and sandy soil that gets you 2000psf. Not too bad.

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

Re: Soils Reports under CBC 1802.2

In a message dated 2/15/08 12:23:24 PM, chuckuc@pacbell.net writes:

Brian
I have one local CBO who doing the same (& another who is can't make up
his mind).
Chuck Utzman

Why the indecision? From this side of the fence -- the practicing engineer side -- the BO's are in the enviable position of having *all* the power and of being able to make decisions for the good of society as they see it, WITHOUT having to worry about being sued. Not a bad position to be in; I wish I were in the same position and could actually design what I felt was the best structure for the situation without worrying about having *everyone* second-guessing me because I dropped a 4th decimal place in some arcane wind calculation or missed some obscure code requirement that's hanging on from many decades ago but just never got rooted out.

I'm dead serious.

End of vent.

Ralph

**************
The year's hottest artists on the red carpet at the Grammy Awards. Go to AOL Music.
(http://music.aol.com/grammys?NCID=aolcmp00300000002565)

Re: Soils Reports under CBC 1802.2

Brian
I have one local CBO who doing the same (& another who is can't make up
his mind).
Chuck Utzman

Chris Slater wrote:
> I know of at least one jurisdiction that is only requiring them in
> areas of unknown soil. If it's a new house in an area with known soil
> properties (from past development) they are not requiring reports to
> be done.
>
> Chris
>
> On Fri, Feb 15, 2008 at 11:13 AM, <Jnapd@aol.com> wrote:
>
>>
>> Brian
>>
>> As the building official, the Building code grants you, the authority to
>> decide what projects need soils report and which don't. Most remodel and
>> additions should not be required unless there is soils related distress on
>> the existing building. New housing developments and commercial yes.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> In a message dated 2/15/2008 8:19:55 A.M. Pacific Standard Time,
>> bgerving@ci.eureka.ca.gov writes:
>> Unfortunately, there's not much of a loop hole there. The exception to
>> 1802.2.7, item 2 only applies to the site-specific study for peak ground
>> acceleration taking into account soil amplification effects.
>>
>> All of the other soils report requirements dictated in Section 1802.6
>> still have to be addressed, and in SDCs D, E, and F, so do the rest of
>> the items contained in 1802.2.7, items 1 and 2.
>>
>> All projects in our jurisdiction are assigned to SDC E or F, and we are
>> really struggling with the fact that we're forced to require soils
>> reports for even small projects on infill lots.
>>
>>
>> Brian Gerving
>> Plans Examiner
>> City of Eureka Building Department
>>
>> -----Original Message-----
>> From: Thor Matteson [mailto:thor@yosemite.net]
>> Sent: Thursday, February 14, 2008 6:28 AM
>> To: SEAINT
>> Subject: Soils Reports under CBC 1802.2
>>
>> I keep hoping to find a loop-hole....
>>
>> Section 1802.2.7, item 2, Exception states: "A site-specific study need
>> not
>> be performed, provided that peak ground acceleration equal to
>> (S-sub-DS)/2.5
>> is used, where S-sub-DS is determined in accordance with Section 21.2.1
>> of
>> ASCE-7"
>>
>>
>>
>>
>>
>>
>> ________________________________
>> The year's hottest artists on the red carpet at the Grammy Awards. AOL Music
>> takes you there.
>>
>
> ******* ****** ******* ******** ******* ******* ******* ***
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> *
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Re: Soils Reports under CBC 1802.2

I know of at least one jurisdiction that is only requiring them in
areas of unknown soil. If it's a new house in an area with known soil
properties (from past development) they are not requiring reports to
be done.

Chris

On Fri, Feb 15, 2008 at 11:13 AM, <Jnapd@aol.com> wrote:
>
>
>
> Brian
>
> As the building official, the Building code grants you, the authority to
> decide what projects need soils report and which don't. Most remodel and
> additions should not be required unless there is soils related distress on
> the existing building. New housing developments and commercial yes.
>
>
>
>
>
>
>
>
>
>
> In a message dated 2/15/2008 8:19:55 A.M. Pacific Standard Time,
> bgerving@ci.eureka.ca.gov writes:
> Unfortunately, there's not much of a loop hole there. The exception to
> 1802.2.7, item 2 only applies to the site-specific study for peak ground
> acceleration taking into account soil amplification effects.
>
> All of the other soils report requirements dictated in Section 1802.6
> still have to be addressed, and in SDCs D, E, and F, so do the rest of
> the items contained in 1802.2.7, items 1 and 2.
>
> All projects in our jurisdiction are assigned to SDC E or F, and we are
> really struggling with the fact that we're forced to require soils
> reports for even small projects on infill lots.
>
>
> Brian Gerving
> Plans Examiner
> City of Eureka Building Department
>
> -----Original Message-----
> From: Thor Matteson [mailto:thor@yosemite.net]
> Sent: Thursday, February 14, 2008 6:28 AM
> To: SEAINT
> Subject: Soils Reports under CBC 1802.2
>
> I keep hoping to find a loop-hole....
>
> Section 1802.2.7, item 2, Exception states: "A site-specific study need
> not
> be performed, provided that peak ground acceleration equal to
> (S-sub-DS)/2.5
> is used, where S-sub-DS is determined in accordance with Section 21.2.1
> of
> ASCE-7"
>
>
>
>
>
>
> ________________________________
> The year's hottest artists on the red carpet at the Grammy Awards. AOL Music
> takes you there.

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

Re: Soils Reports under CBC 1802.2

Brian

As the building official, the Building code grants you, the authority to decide what projects need soils report and which don't. Most remodel and additions should not be required unless there is soils related distress on the existing building. New housing developments and commercial yes.

In a message dated 2/15/2008 8:19:55 A.M. Pacific Standard Time, bgerving@ci.eureka.ca.gov writes:

Unfortunately, there's not much of a loop hole there. The exception to
1802.2.7, item 2 only applies to the site-specific study for peak ground
acceleration taking into account soil amplification effects.

All of the other soils report requirements dictated in Section 1802.6
still have to be addressed, and in SDCs D, E, and F, so do the rest of
the items contained in 1802.2.7, items 1 and 2.

All projects in our jurisdiction are assigned to SDC E or F, and we are
really struggling with the fact that we're forced to require soils
reports for even small projects on infill lots.

Brian Gerving
Plans Examiner
City of Eureka Building Department

-----Original Message-----
From: Thor Matteson [mailto:thor@yosemite.net]
Sent: Thursday, February 14, 2008 6:28 AM
To: SEAINT
Subject: Soils Reports under CBC 1802.2

I keep hoping to find a loop-hole....

Section 1802.2.7, item 2, Exception states: "A site-specific study need
not
be performed, provided that peak ground acceleration equal to
(S-sub-DS)/2.5
is used, where S-sub-DS is determined in accordance with Section 21.2.1
of
ASCE-7"

The year's hottest artists on the red carpet at the Grammy Awards. AOL Music takes you there.

RE: IBC 2007 Wind calcs.

Scott,

I am going to get a bit testy (yes, you all probably already believe I was
testy).

From my perspective, we are not that far apart. I definitely believe that
there is a lot of overly complex stuff in the codes. I also have some
issues with the 3 year cycle. I do believe that change in necessary, but
also believe that sometimes we seem to do change just to do change.

Where we will disagree is the pointing of figures. While I am not really on
any code committees, I know quite few people who are. And frankly, I take
offense to your comments. While they might apply to some that are involved
with the code development process, I consider them rather slanderous when
aimed at many that are involved with code development. There are lot of
good people who dontate their time and money trying to make things better
only to get dumped on by the likes of you.

I personally believe that if you are going to point fingers, then you also
need to point them at yourself and every other engineer out there that
cannot be bothered to be part of the process for any number of reasons (many
of which are completely valid and reasonable). It is the lack of a desire
(or ability) by the engineering community at large to be part of the process
that allows some with vested interests to drive the process in ways that it
should not be driven.

I understand the frustration. In many ways I share it. But, I have never
understood how "back seat driving" the code process will solve anything. It
is a lot easier to complain about stuff then to actually propose solutions
that will work. What seems easy to you might not be so easy if you were
more involved in the process. After all, how many times has some architect
complained about something that a structural engineer did and maybe said
some to the effect of "it should be easy to do it this way instead" when in
reality it is far from easy?

And frankly, if the biggest gripe is having to pay $1200 every three years,
then as blunt and brutal as it might be, my response is get over it. Like
EVERY business, there are costs associated with operating. I dare say that
there are lots of other professions that have to shell a LOT more money than
$1200 in order to operate with the tools and information that they need.

OK, I will try to get off my soapbox now.

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Haan, Scott M POA [mailto:Scott.M.Haan@usace.army.mil]
Sent: Thursday, February 14, 2008 9:10 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

In Alaska it could be wind or seismic. Kind of depends on the location and
building. Welcome to the IBC CA. You non West coast people griping about
the seismic - you're right it sucks. They keep changing it every three
years just like the concrete anchors, wind, snow, load combos, steel seismic
code, IBC chapter 23 etc... etc... etc... But you know what I feel safer
every three years knowing the buildings I walk into were designed with $1200
worth of new code books.

The building code illuminati have become a selfperpetuating, promoting
their building materials, seminar giving, design example book writing,
software writing, buy $1200 worth of code books every couple of years
behemoth. Beware of the building code writing industrial complex.

The codes are supposed to keep people safe. When building codes are
complicated there will be more mistakes and it won't keep people as safe. I
have been updating my ASCE 7-95 wind spreadsheet to the 7-05 and it is
complicated. I remember the UBC and it wasn't complicated.

Although everyone on this list service is high on the intelligence scale for
engineers, the building codes need to be catered to the lowest common
denominator. If you don't think so, you're one of the building code
illuminati.

RE: Soils Reports under CBC 1802.2

Unfortunately, there's not much of a loop hole there. The exception to
1802.2.7, item 2 only applies to the site-specific study for peak ground
acceleration taking into account soil amplification effects.

All of the other soils report requirements dictated in Section 1802.6
still have to be addressed, and in SDCs D, E, and F, so do the rest of
the items contained in 1802.2.7, items 1 and 2.

All projects in our jurisdiction are assigned to SDC E or F, and we are
really struggling with the fact that we're forced to require soils
reports for even small projects on infill lots.

Brian Gerving
Plans Examiner
City of Eureka Building Department

-----Original Message-----
From: Thor Matteson [mailto:thor@yosemite.net]
Sent: Thursday, February 14, 2008 6:28 AM
To: SEAINT
Subject: Soils Reports under CBC 1802.2

I keep hoping to find a loop-hole....

Section 1802.2.7, item 2, Exception states: "A site-specific study need
not
be performed, provided that peak ground acceleration equal to
(S-sub-DS)/2.5
is used, where S-sub-DS is determined in accordance with Section 21.2.1
of
ASCE-7"

The above exception *looks* like it's intended to let you "over-design"
(GOD, I hate that term...) for seismic and avoid having a site-specific
soils report. BUT-- when you go to Section 21.2.1 of ASCE-7, there is
no
mention of S-sub-DS. In fact S-sub-DS is barely mentioned in Chapter 21
at
all. Chapter 21 deals with site-specific accelerations anyway, so this
is
sort of a circular argument ("you don't need a site-specific soils
survey if
you have done a site-specific soils survey").

Could it be that the reference to Section 21.2.1 is incorrect? If so,
which
section should be referenced instead?

Thanks for any hints....

Our office is hoping that reports from the Natural Resources
Conservation
Service (NRCS, part of the US Dept of Agriculture) website will be
acceptable for 'run-of-the-mill' projects. They give the USCS soil
types of
SM, GP, SW, etc. that can then be cross-referenced with IBC/CBC Table
1804.2
for soil bearing values.

The NRCS "Web Soil Survey" site is:
http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx
You might have to go to this site first to load the application:
http://websoilsurvey.nrcs.usda.gov/app/
I have not spent too much time there, but it has an *amazing* amount of
info. We all paid for it---can we at least USE it now, please??

Thor Matteson
www.shearwalls.com

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

RE: IBC 2007 Wind calcs.

Nope. I try to avoid it like the plague...which in reality is NOT hard.
The vast majority of building does NOT fall into the flexible buidling
range. Signs frequently do...and that is where I have primarily encountered
that chocolate cupcake with a turd in the middle.

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Haan, Scott M POA [mailto:Scott.M.Haan@usace.army.mil]
Sent: Thursday, February 14, 2008 9:29 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

Scott.

The dudes who came up the flexible buildings wind formulas must have just
walked through a burning field of seers sage.

Do you have the flexible building gust factor formula memorized? I guess a
typical engineer could hire RWDI to find their wind pressures for them if
they had a flexible building.

Scott.

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Thursday, February 14, 2008 4:39 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

I will offer a similar response to you as I did to Bill. While the
differences might not be much for typical jobs that you design, do you do
much work in high wind/hurricane areas? Those differences between a
conservative approach in 140 mph wind zones and a more "fine tuned" method
can have some rather big differences. You can get to points with the little
change in the 3 to 5 psf can have a big difference.

And I will say it again, I understand that it is more complex, which might
mean it takes longer. And I agree that there are some complexities that are
a waste (the seemingly 40 different wind pressure zones for MWFRS pressures
under Method 1...I can see the need for all the different zones for C&C, but
not for MWFRS). But, there is a difference between it being more work and
tougher to understand. I would argue that it is not that tough to get, but
I will agree that it might take longer. Personally, having used ASCE 7 wind
provisions for years, I don't find that it takes me all that long...and find
that there are other stupid crap in the codes that are much more worth
griping and battling over than differences between UBC wind provisions and
ASCE 7 "typical" wind provisions. Now, if you want to gripe about the
flexible building provisions, then I will be right there with you...they
seems to require a PhD to deal with.

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Paul Feather [mailto:PFeather@se-solutions.net]
Sent: Thursday, February 14, 2008 7:38 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

It's not so much we are having trouble with the wind provisions, it's just
the effort isn't warranted. I agree the general method is not
over-whelming, despite my earlier post, but why do I want to go through all
the machinations to derive a wind pressure of 17.4 psf net instead of 20 psf
I can calculate in 30 seconds and apply in a straight horizontal projection?
The conservatism is non-existent for most structures, the wind forces are
simply not controlling over seismic, and the average structure can absorb
that conservatism with ease. I have worked with both methods in multiple
states for many years, so it isn't some new experience for me; the real
level of conservatism is not that great a difference.

You may get pressures for method one in a minute, but you will be applying
12 extra load cases to get design forces.

And the new load case provisions (relevant to UBC)requiring .6DL for seismic
is absurd.

I for one will take "dumbed down" unless I really need the more analytical
method. For the majority of applications be a little conservative and spend
the time on the rest of the design. Even seismic design, you don't try and
perform highly analytical dynamic methods for simple structures.

Paul Feather PE, SE
pfeather@SE-Solutions.net
www.SE-Solutions.net

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Thursday, February 14, 2008 4:23 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

I don't disagree. The current ASCE 7 methods are more complicated than what
was in the last few versions of the BOCA code...and those last few versions
of the BOCA code were more complicated than what has been in the 1997 UBC. A
lot of the added complexity that now appears in ASCE 7 compared to older
versions of ASCE 7/BOCA code do seem as overkill to me.

But, I will note that the UBC wind provisions were rather "dumbed down".
Note I don't say this to offend anyone, but it is a good simple way to put
it. UBC provisions are VERY simplified versions of the basic intent of ASCE
7, which a to a large degree a crap load on conservatism in them. And that
is likely why Stan is finding pressures that are less than what he is used
to...the UBC method is conservative, which means that it applies to more
situations without having to do much additional work. A lot of the
"complexity" in the ASCE 7 is that you have more "branches" in the path,
which means the loads can be more talyored to your specific building and
also means you can end up with less conservative loads. Personally, I think
that have take it too far with the available "branches", but I have also
traditionally used versions that are more complex than the UBC.

My point is that still with that complexity, neither method 1 or method 2
are that complex in my opinion, unless you get into the flexible building
scenario. Method 1 is more of a pain since it produces more "zones" with
different pressures. As a result, I do tend to use Method 2 for my calcs,
but I will use Method 1 to get some down and dirty pressures to get a feel
for where things are. I can literally get pressures out of Method 1 in
about a minute or so. Besides, topograpihcal effects tend to bump you out
of Method 1 right darn quick.

While I like seismic design as well, I will take having to deal with the
wind provisions LIGHT YEARS before messing with seismic. And that is why I
am kind of surprised from all the grumbling from California. I have to
admit that I would not think that engineers who can handle the complexities
of the seismic provisions should have any trouble with the wind provisions.
Frankly, to me, the wind provisions are cake next to the seismic stuff.

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Haan, Scott M POA [mailto:Scott.M.Haan@usace.army.mil]
Sent: Thursday, February 14, 2008 5:58 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

Scott.

Compared to the UBC, all the ASCE 7 methods are more complicated. I agree
with people who said use the analytical method for a rigid building is the
easiest way because there aren't 10 different zones etc... etc... but you
still have to have a spreadsheet to calculate the pressures.

I think if I had to design a flexible building I would send chocolate
cupcakes with turds in the middle to the ASCE7 wind committee have a
supercomputer to calculate the gust factor.

Scott.

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Thursday, February 14, 2008 9:58 AM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

I want to say that this method is more or less based off the simplified
method that Washington has produce and has been mentioned by others.

Personally, while I find there to be some complexities that I don't feel are
necessarily needed in the current ASCE 7 wind provisions, I don't find them
that difficult to use...including Method 1. I find that I can pump out wind
pressures in method 1 in very short order. It does take more time to use
those pressures to analyze stuff in MWFRS since they now have corner
pressures and such...but you don't really gain that much compared to older
more "uniform" pressures except for some buildings that might be rather
succeptible to torsional effects. But it does help that I have been using
the ASCE 7 methods for a LONG time, while engineers in CA are more used to
only using the simplified methods that were in the UBC.

I would be the first to agree that ASCE 7 has gone of the deep end to some
degree in "sharpening the pencil" for wind provisions, but I am not sure
that I would liken them to a doctoral thesis (unless you are talking about
the wind provisions for signs or flexible structures or dynamically
sensitive structures and have to start calculating gust coefficients).

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Matthew [mailto:sandman21@gmail.com]
Sent: Thursday, February 14, 2008 12:48 PM
To: seaint@seaint.org
Subject: Re: IBC 2007 Wind calcs.

You can also try using
http://www.documents.dgs.ca.gov/dsa/pubs/IR-16-7_WindLoad_12-18-07.pdf

Matthew

On Thu, Feb 14, 2008 at 9:34 AM, Paul Feather
<PFeather@se-solutions.net> wrote:

Stan,

First off, the simplified method is anything but simple.
We
use the
general method (method 2) for everything and get more
consistent results
easier. The simplified method is derived from metal
building
manufacturer methods, and for anything but a metal
building
results in a
complete book keeping atrocity.

You are looking at 25 degrees area B. The way the
simplified method
works this is just one small area that cannot be applied
in
the same
thinking as the UBC horizontal projected area. You have
to
add the area
B to the Area E uplift, basically all areas A through H
get
applied
simultaneously as one load case. Then you rotate the
building reference
corner and apply the whole thing again for all four
reference corners.

Get away from the simplified methods and you will
simplify
your life,
while getting something closer to what you are used to.
I
don't believe
the ASCE wind provisions could be any more convoluted
and
difficult to
apply to real world engineering if we tried. The UBC
methods were
derived as a conservative simplification of the ASCE
provisions years
ago, and we desperately need to achieve something
similar
again.
Spending three days on a doctoral thesis to develop
simple
wind
pressures as opposed to working on load path and quality
engineering is
counter-productive, and saving 1.4 psf in wind pressure
only
matters to
mass produced square boxes trying to be paper thin.

Paul Feather PE, SE
pfeather@SE-Solutions.net

www.SE-Solutions.net <http://www.se-solutions.net/>

-----Original Message-----
From: sscholl2@juno.com [mailto:sscholl2@juno.com]

Sent: Thursday, February 14, 2008 9:09 AM
To: seaint@seaint.org
Subject: IBC 2007 Wind calcs.

After 40 yrs. of doing UBC calcs. I am attempting to do
my
first IBC
calcs. and need help, even after attending a seminar,
which
seemed to
cover lots of things but not this.

For a simple house, using 6.4 Method 1 Simplified
Procedure,
I cannot
get a reasonable wind pressure of something between 15
psf
and 25 psf.

From 6.4.2.1 <http://6.4.2.1/> , I get p s= 1.0 (1.0)
1.0
(2.3) = 2.3 psf which is
unrealistic. This is using Fig. 6-2, exposure B, h=30
ft.,
Kzt =1
and I=1

Can someone point out my omissions/errors?

Stan Scholl, P.E.
Laguna Beach, CA

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