Structural Engineering: 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.

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell@umich.edu]
Sent: Thursday, February 14, 2008 4:24 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

I am not sure that codes are meant to be "cook books", even if that is what
they have become or perceived to have become. Code are meant to be minimum
standards that are to be met, but it is still supposed to be the engineer
that uses engineernig judgement to determine if that is enough or if more in
needed.

I agree that it should not be a puzzle. But, I don't find the wind
provisions to be that puzzling (there is lots of other stuff that is puzzling
at times). If you want to continue your analogies, I consider current wind
provisions (except the felxible building stuff...those are a puzzle at
times...and I liked your chocolate cupcake with a turd idea) to be a more
extensive recipe in the cook book than the recipe that was in the UBC...it is
not any tougher to figure out, per se, but takes longer the make/cook...which
is due to the fact that the recipe is no longer just for chocolate cupcakes
(California), but also for vanilla, strawberry, and swirl cupcakes (other
locations with higher wind issues) (turd in middle optional).

Regards,

Scott
Adrian, MI

-----Original Message-----
From: Haan, Scott M POA [mailto:Scott.M.Haan@usace.army.mil]
Sent: Thursday, February 14, 2008 7:59 PM
To: seaint@seaint.org
Subject: RE: IBC 2007 Wind calcs.

I just put it in my spreadsheet after reading some of the posts on this
thread. The code is supposed to be a cook book not a puzzle.

-----Original Message-----
From: chris.slater@gmail.com [mailto:chris.slater@gmail.com] On Behalf Of
Chris Slater
Sent: Thursday, February 14, 2008 3:40 PM
To: seaint@seaint.org
Subject: Re: IBC 2007 Wind calcs.

Right. I account for that by calculating a 10 psf load (that's the W1-10,
W2-10, etc) and if that's greater than what I come up with by the other
method, I use it.

On Thu, Feb 14, 2008 at 4:03 PM, Haan, Scott M POA
<Scott.M.Haan@usace.army.mil> wrote:
> If you read the guide - I think per ASCE 7-05 6.1.4.1 you are supposed
> to use a minimum of 10 psf projected on the vertical surface when you
> have no horizontal pressure component on the roof. I rest my case:
> not as easy as the UBC.
>
>
>
> -----Original Message-----
> From: chris.slater@gmail.com [mailto:chris.slater@gmail.com] On
> Behalf Of Chris Slater
> Sent: Thursday, February 14, 2008 2:46 PM
> To: seaint@seaint.org
> Subject: Re: IBC 2007 Wind calcs.
>
> All of this talk is making me worry that we're doing something
> horribly wrong...
>
> I put up a sample of the way we're doing our wind calcs here:
> http://www.examplecalcs.com/hosted/18329.pdf
>
> I use a program to generate the A, B, C and D loads. If the B and D
> loads are negative, I just use 0. Then I generate my wind loads by
> taking the B pressure from the ridge down to the plate, and the A
> pressure from the plate to the middle of the wall height. In the
> example I posted, W1 and W2 are calculated that way.
>
> For gable ends, or lower levels, I just use the A load from the top
> of the projected area to the middle of the lower wall, which is how I
> got
> W3 and W4 in the example.
>
> For long buildings, I will sometimes use the C and D loads for the
> section of the building that is more than 2a from the corners, but in
> general, I just use the A and B loads since these tend to be lower
> than the projected area winds we used in the old UBC code.
>
> It's not simple, but it's not incredibly complicated either. Which
> makes me worried. Am I missing something, or does this seem like a
> reasonable approach.
>
> Chris
>
> On Thu, Feb 14, 2008 at 2:58 PM, Haan, Scott M POA
> <Scott.M.Haan@usace.army.mil> wrote:
> > 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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> >
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