Interior Shearwalls for Wood Framed Structures
Interior Shearwalls for Wood Framed Structures
2
medeek (Structural)
(OP)
I'm still not sure that I am entirely satisfied with my treatment of interior shearwalls for residential work lately however I have come a long way in the way I analyze each situation a little more carefully than before. Thanks to some good texts and some excellent advice and feedback from engineers on this forum I"ve managed to cobble together an acceptable interior shearwall detail drawing. I have posted it to my CAD library here for all who are interested:
http://design.medeek.com/cad/cadlibrary.html
My reason for posting this structural detail drawing is to elicit further comments or recommendations which would hopefully improve this structural detail even further, not only for my own use but for other engineers who face similar challenges with residential structural engineering.
I am sure there are other situations or configurations which this detail(s) does not adequately cover and I would be interested in exploring those as well.
http://design.medeek.com/cad/cadlibrary.html
My reason for posting this structural detail drawing is to elicit further comments or recommendations which would hopefully improve this structural detail even further, not only for my own use but for other engineers who face similar challenges with residential structural engineering.
I am sure there are other situations or configurations which this detail(s) does not adequately cover and I would be interested in exploring those as well.
A confused student is a good student.






RE: Interior Shearwalls for Wood Framed Structures
The contractors that I work with almost never get an anchor bolt in the right place for a hold down. Most of the time these are drill and epoxy. It's ok to prescribe an embedded bolt, but have an option for a post installed anchor
You may want to specify shear nailing for the shear wall to the elements above / below. Not the sheathing nailing, but the shear connection between the wall and the blocking, etc.
Nails come in many flavors. Most gun nails are "sinker" dimensions or so. "Common" nails aren't common. Check out ESR 1539 for equivalent nailings to code minimum attachments.
http://www.icc-es.org/Reports/pdf_files/ESR-1539.p...
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Interior Shearwalls for Wood Framed Structures
I haven't decided on what is the best option or way of calling out an alternative to the cast in place bolts, still thinking about that.
I see 16d nails being called out in many structural details I've studied but maybe they are implying a box nail (0.135" DIA) in these call outs.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
RE: Interior Shearwalls for Wood Framed Structures
Most of my residential projects are in a high wind region (155 mph ultimate -> 120 mph ASD) so some consideration for nailing the roof diaphragm for out of plane forces is in order. I'm wondering what other engineers are typically doing for this sort of thing. So far I haven't gone so far as to call out special nailing requirements for perimeter nailing versus interior nailing but if I were to follow the WFCM prescriptive tables the nailing specification for the roof sheathing could become quite complicated. Would this be too much to expect from your average residential contractor/carpenter?
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
RE: Interior Shearwalls for Wood Framed Structures
Looking at the interior shearwall example in the drawing above you will note that I've shown a double 2x bottom plate, which it turns out is completely wrong. Somewhere I had learned that when the ASD unit shear of a shearwall exceeded 350 plf that it should have a 3x or (2) 2x sill plate. My first mistake here was not differentiating between a sill plate and a bottom plate (sole plate). They can be one and the same but with a TJI floor they are obviously not the same thing.
If I was to use a 3x sill plate under some of my higher loaded shearwalls then all of the sill plates would need to be 3x or double 2x otherwise the TJI floor would be all wonky (at different levels). Using a 3x bottom plate really doesn't make sense either since there are no adjoining panel edges at the bottom of the shearwall, interior or exterior.
Digging a little deeper I find that the 2006 IBC 2305.1.11 required a 3x sill plate for an ASD shearwall load over 350 plf. This was omitted from
the 2009 / 2012 IBC due to plate washer requirements (see SDPWS 4.3.6.4.3) and it appears that most of the shearwall code in the IBC was removed and it now references the SDPWS. The only reference I find pertaining to a 3x member in both the SDPWS-2008 and the SDPWS-2015 is for adjoining / abutting panel edges. Is there any current code requirement for a 3x sole / sill plate at upper floors or even at foundation levels?
It appears I've been operating with outdated information.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
With regards to a shearwall framed on top of a TJI floor. If bolt diameter is maximized and shearwall length is too short to realistically add more bolts one could always add flat blocking between the TJI/lumber joists similar to what is shown in the portal frame details. In this way the TJI floor remains at the same level as the other floors framed under non-shearwalls.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
http://www.eng-tips.com/viewthread.cfm?qid=273357
Looks like I'm not too far off.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
http://www.strongtie.com/ftp/articles/2010-Buildin...
I guess this is old news for pretty much everyone but I'm surprised nobody called me on it with regards to the detail drawing above.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
I wonder how many practicing engineers and building officials are still using the 2006 code and may not even be aware of the changes that removed the 3x sill plate requirement. I recently specified 3x sill plates for a local residential job and the building dept. did not call me on it. In fact, their inspector noticed the builder had not installed the 3x sill plates and had subsequently required a letter from me for a fix. Next time I stop in I'll bring it up to see where they stand and hopefully eliminate any future confusion as well as apologize for my outdated methods.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
RE: Interior Shearwalls for Wood Framed Structures
The truss calculator is probably the largest project I've ever programmed but is still mostly incomplete as it currently stands. It is primarily an academic exercise on analyzing MPC trusses per the TPI 1. In order to make is a usable design tool there is a to-do list a mile long that I need to complete. Unfortunately, lack of a way to fund the project severely limits my progress at the moment. I have had a number of solar panel companies interested in its progression contact me with questions and suggestions so it may have some real world potential.
A confused student is a good student.
RE: Interior Shearwalls for Wood Framed Structures
RE: Interior Shearwalls for Wood Framed Structures
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com