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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