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Author
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Topic: Shear Walls
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zenhowie1
Posts: 19
Registered: Jan 2003
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posted 01-16-2003 12:53 PM
   
We have been enforcing the alternate braced wall panel code here in the City of Allen for several months now, and getting a tremendous amount of discord from the builders because "no other city is enforcing it". We have asked for engineer's design for any braced wall less than 32" and there are a number of home builder companys that just can't seem to comply with this requirement. Are there any other cities in Texas or the nation that is also requiring this section of the code to be met? The Home Builders Assoc have requested a meeting with our building official to discuss the problem.
Thanks for any input, HowardIP: Logged |
tkr
Posts: 587
Registered: Oct 2000
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posted 01-17-2003 05:54 AM
zenhowie1,
We enforce it. We caught some crap from the builders initially about walls less than 32 inches, especially at garage wing walls, having to be engineered.
I sent away for some pamphlets from The American Plywood Association that showed one engineered design that we would accept.
Some have used that design and others have had their own engineer work up other designs (with stamp), while others have had their engineer sign off on the way that they have always built.
Info is on link below.
Hard to believe that the Home Builders Assoc. is having problems with you, they should be having problems with their members.
http://www.icbo.org/ubb/Forum4/HTML/002842.html Good luck IP: Logged |
zenhowie1
Posts: 19
Registered: Jan 2003
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posted 01-17-2003 11:15 AM
Thanks tkr. We accept the APA design here as well as the Simpson Strong wall, since both are engineered designs. There was so much confusion getting the plans right, at first, we just decided to have all the plans stamped by an engineer. BTW, from which city do you hail? HowieIP: Logged |
tkr
Posts: 587
Registered: Oct 2000
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posted 01-17-2003 01:13 PM
zen,
Easton. The biggest problem we have run into now, is the fact that I have to carry everyone's different design with me for foundation and framing inspections, so that I can see that they are to the designer's specs. Kinda dug my own hole, oh well!
We are in the process of requiring them on each set of approved plans. Baby steps, you know?[This message has been edited by tkr (edited 01-17-2003).] IP: Logged |
zenhowie1
Posts: 19
Registered: Jan 2003
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posted 01-21-2003 05:29 AM
We require the builders to have a set of stamped plans on site for all related inspections. Maybe you guys should consider implemeting that to save hauling all those plans around in your vehicle.
HowieIP: Logged |
George Roberts
Posts: 527
Registered: Dec 2001
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posted 01-21-2003 07:27 AM
Zenhowie1 ----Perhaps you could supply approved perscriptive plans to the builders who are unable to comply. IP: Logged |
DHagin
Posts: 221
Registered: Aug 2000
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posted 01-21-2003 12:42 PM
we also enforce the alt bwp requirements. and we too have and continue to get flak from owners, builders on the 32" minimum (most are on the path as we have been enforcing since the beginning).simpson strong walls are accepted on a per case basis, but have heard that this is not a cheap alternative. here in coastal WA with seismic zone 3 and 100 mph winds, it's often not a difficult sell when we point out that our combination of local factors increase the structural requirements. IP: Logged |
zenhowie1
Posts: 19
Registered: Jan 2003
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posted 01-21-2003 01:34 PM
George, most of the builders that are not complying are those that are concerned with costs, rather than methods, we supplied them with numerous options, and it seems the more we offered, the more they got confused. Our residential planner here spent temendous amouts of time teaching the architects and engineers the concepts, but as usual, it all came down to the money with the builders resisting the design. To make matters worse, we began enforcing IRC 802.3.1 with the rafter tie issue and that turned into a worse nightmare. Eventually we required them to provide us with roof calculations and the required mechanical connection needed to resist roof thrust when the joists ran perpendicular to the rafters, or there were no joists at all, such as a vaulted ceiling and ridge beams weren't used. IP: Logged |
tkr
Posts: 587
Registered: Oct 2000
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posted 01-21-2003 03:24 PM
quote:
Originally posted by George Roberts:
Zenhowie1 ----Perhaps you could supply approved perscriptive plans to the builders who are unable to comply.
George Roberts,
The Building Code persciptive methods are for walls less than 4 feet down to 32 inches.
Less than that, one would need to supply an engineer's design.
Are you suggesting that, if one builder hired and paid an engineer to design a plan for this application, the Building Dept. can and should hand this info out to all the other builders for free? Doesn't seem fair to me. You are an engineer, what would be your thoughts if I did that with your design?
Just a question.
I ask, because I have had builders ask, "What is everyone else doing in this regard?IP: Logged |
zenhowie1
Posts: 19
Registered: Jan 2003
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posted 01-22-2003 05:43 AM
tkr is right. There are no prescriptive methods in the code for wall panels less than 32". There are engineered designs that are available such as the APA shear wall and the Simpson Strong wall, but it's up to the municipal code authority to accept them. In many cases these won't work for a particular structure, so a engineer design is necessary.IP: Logged |
George Roberts
Posts: 527
Registered: Dec 2001
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posted 01-22-2003 01:41 PM
Like most engineers I have a set of prepackaged design details. They have as much detail as the APA shows for their shear walls.When my details are submitted to the building inspector they become part of the public record. They are available thru the Freedom of Information Act or simply by asking. I have no "rights" in the material. If an AHJ wants to accept the APA design, there is no reason he should not distribute that design to others. Once he accepts my design there is no reason for him to not distribute it to others. zenhowie1 --- A cheap alternative to the APA method is to build a "truss" with the garage door in it. The truss shops around here will do that (no engineering cost) if you purchase trusses from them. I build a truss from 2x4's for the whole garage wall. The "edge" (plates, headers, and jacks) is trippled 2x4s. 2x4s at 45 degrees fills in around the door. 2 layers of 1/2" or 3/4" ply screwed to one face. I use standard mud sill anchors on the bottom. This is similar to the FEMA construction for tornado shelters. The cost is reasonable. IP: Logged |
tkr
Posts: 587
Registered: Oct 2000
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posted 01-22-2003 04:56 PM
Interesting, informative, and appreciated.
Thank you, George.IP: Logged |
zenhowie1
Posts: 19
Registered: Jan 2003
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posted 01-23-2003 05:49 AM
Thanks for the info George. I'll pass it along to the buidlers here.
It seems the engineers here in the Dallas area started with the shear wall designs from scratch, having no pre-existing designs(in house) available. We have had some builders with plans that were over-engineered, in our opinion, and apparently to the home builders too. Often times they have taken them back to the engineer firm, and they completely revamped the plans, removing most of the components in the overall shear wall construction. Its been like an evovling process here with the SW requirements. Since these code requirements were never enforced, it has been a learning experience for all invovled. The IRC mentions a 'design collector' in 602.10.11, and no one has a good definition(or clue) of the term. Another one is 'drag strut' that we often see on the engineered plans. Thats a new one to me, although I understand the intended use now, after seeing them on the intended structures. IP: Logged |
DHagin
Posts: 221
Registered: Aug 2000
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posted 01-24-2003 10:15 AM
[/b][/QUOTE]
...I ask, because I have had builders ask, "What is everyone else doing in this regard?[/B][/QUOTE] our jurisdiction hired an engineer a few years ago to develop a "prescriptive" pole building design for use in the county. now, we have 80, 90, 100 mph wind zones and B, C, D exposures.
Q:guess what we got from the engineer?
A:9 different designs...humf the b.o. looked at all the info, came up with 2 designs that work with most of the county. 100 mph c&d still need to be engineered. i believe the idea of the jurisdiction hiring an engineer is a good one. understand that i am not an engineer and don't understand all the complexities of a "one size fits all" solution. i have, however, worked in jurisdictions that have a "prescriptive" designs for various cases. this is also a good selling point when trying to gain compliance. "we hired the engineer so you don't have to, here's the design for 'free'..." IP: Logged |
tkr
Posts: 587
Registered: Oct 2000
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posted 01-24-2003 06:04 PM
Sounds like someone in your jurisdiction has some big shoulders!!!!
Good luck.IP: Logged |
Lou Marks
Posts: 370
Registered: Feb 2000
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posted 01-24-2003 07:03 PM
When the issue first came up I thought the same as most. However, after searching the internet I found a wealth of information to assist me in coming up with a number of prescriptive solutions. I'll include them below to make it easy for others to research and determine how they would like to proceed. I hope you find the information of use: http://www.ceewal.com/index8.htm
http://www.awc.org/technical/considerations.html http://www.state.il.us/iema/prep.htm http://www.engr.sjsu.edu/dmerrick/shearwalls/ http://www.flash.org/
http://www.ce.jhu.edu/aawe/jan98.htm
http://www.millibar.com/hcanen.html
http://www.huduser.org/publications/destech/shear.html
http://www.duraproducts.net/
http://www.abag.ca.gov/bayarea/eqmaps/fixit/ch3/sld001.htm
http://www.statefarm.com/consumer/vhouse/articles/articles.htm
http://home.socal.rr.com/hapnet/
http://www.awc.org/Publications/papers/WDFPLine.pdf
IP: Logged |
George Roberts
Posts: 527
Registered: Dec 2001
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posted 01-25-2003 07:50 AM
Just a word of politeness.The referenced documents have copyrights. It is always nice to ask for permission to copy or distribute them before you do so. (Most if not all of the groups will give you that permission.)
IP: Logged |
Don Andrews
Posts: 23
Registered: Oct 2001
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posted 01-27-2003 10:01 AM
A word regarding inspections of manufactured shearwalls:
With the various manufactured shearwall products, they have specific holddown bolt requirements, including depth and width of concrete. I have found that frequently the concrete contractor is not aware of those requirements and has not widened or deepened the footings to meet the requirements. And yes, I also carry installation instructions with me for all the different brands of shearwall I typically see. Our dept. requires the info to be on the approved plans on the site.IP: Logged |
