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RE: Residential Design Spreadsheet

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um, are you looking for dennis wish? i am not him. (i am on the seaint
list). i think if you search the archives you will find him in some posts.

dennis pantazis

-----Original Message-----
From: Sam Chang [mailto:szchang(--nospam--at)mail.arc.nasa.gov]
Sent: Wednesday, July 26, 2000 8:14 PM
To: Dennis Wish
Subject: RE: Residential Design Spreadsheet


Dennis:

         Got the 97 UBC Lateral Design.xlt from the web.  It is dated
10/16/00 and about 6,885KB in size.  Is that the latest?  Could you send me
the latest or tell me where to get it if not.

Thanks

Sam Chang, SE


At 03:34 PM 7/26/00 -0700, you wrote:
>Dennis sent this to me:
>
>Mark,
>Possibly you can pass this on to the list as I am not a subscriber and can
>not post to it.
>
>The Lateral Design Spreadsheet - flexible analysis provides a wall
>deflection analysis that assumes the wall to be cantilevered. The method
>follows, very closely, the methods presented in the 1998 Wood Design
Seminar
>AND the ICBO Volume II of the Seismic Design Manual. If the wall occurs in
a
>location other than above a wall below, the designer is responsible for
>further analysis to justify the design of the member below which is used to
>resist the reactions on the wall (such as a beam below).
>
>The spreadsheet follows UBC method for lateral force distribution in a
>multi-story building to arrive at a story shear for each level. The
>distribution of shear to resisting walls in each level follows a more
>complicated proportional distribution based on the following design
>assumptions of a series of simply supported beams. The process becomes a
bit
>more complicated when walls do not stack. The following method was created
>to distribute shear to walls which do not align from level to level:
>
>1. Every line of shear from the first floor to the top must be accounted
for
>at each level. If you consider the building to be transparent from roof to
>foundation and place a clear Mylar over the top - each wall that resists
>shear - regardless of the level it occurs on - is represented by a grid
>line. The total grid layout occurs at each level whether a wall occurs at
>that level or not.
>
>2. The tributary areas occurring between grid lines is calculated and the
>shear from the upper level is distributed by proportion into the walls
>below. It becomes a bit more complicated to explain:
>First, the shear at the level under consideration is distributed by
>tributary area into all walls. If a wall occurs above that is between two
>walls in the level below, the force from the wall is distributed to the two
>nearest walls below by proportional distribution the same as you do with a
>simple span beam with a concentrated load placed anywhere on the beam. I
>follow the formula Rleft = Pwall * (L2/(L1+L2)) where L2 is the distance
>from the wall above to the wall reaction at the right of the load.
>
>3. As the loads are cumulated in lower levels, the reactions from the walls
>above are distributed in the same fashion as stated in number 2 above. This
>allows the user to omit and add walls as the program will redistribute the
>loads accordingly.
>
>
>Mark, one thing that disturbs me is the ease in which the spreadsheet is
>simply discounted by some of the respondents. A great deal of effort went
>into the creation of the spreadsheet by myself and others. We placed it on
>the SEAOC website for others to use freely. We expected feedback and
reports
>of errors and inaccuracies - which we fully intended to address. However,
>many users downloaded the software, found a bug or two and simply discarded
>the tool as useless.
>
>The time and energy spent to create this tool were done by dedicated
>engineers who believed they would be contributing a useful tool to their
>peers without expectation of compensation. Over one hundred and fifty names
>were accumulated when the software was first released. Only three or four
>responses were received.
>
>The software was then donated to the public domain and left unprotected on
>the SEAOC server where anyone with spreadsheet skills could take the
>software, improve upon it and offer it back to the community as a
>contribution - none have.
>
>Personally, I do use the spreadsheet and found the results consistent with
>hand analysis that I perform. There are issues that remain unanswered by
the
>code writers and until that happens, neither our spreadsheet or the two
>commercial products on the market will meet the needs of everyone in the
>profession.
>
>I am amazed at how often it is easier to criticize than it is to contribute
>something useful. For those of you who would like to invest a bit of time
in
>learning to use the spreadsheet, I remain available to discuss your
concerns
>rather than receive them second hand.
>
>Regards,
>Dennis S. Wish, PE
>The Structuralist Administrator for:
>http://www.structuralist.net
>AEC-Residential Listservice
>admin(--nospam--at)structuralist.net
>(208) 361-5447 E-Fax
>
>
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