Home Page link

roof thrust problem

Home| Search | About
Login Password
Register Now! Lost Password?

Building Construction - Building Construction Industry Discussions. 

Page 2 of 2       << first < 1 2 Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
roof thrust problem jbusboom 08-22-2006
If you were  Registered and logged in, you could reply and use other advanced thread options
Posted by on August 23, 2006, 4:55 pm
I don't know what glide shoes are and couldn't find a good explanation
on the net...the trusses I am using are made onsite and use plywood
gussets at all of the intersections. A picture can be found here:

http://www.barnplans.com/trusses.html

It's the top picture, although you can't see the truss very well at
that angle. Other pictures on the site show a better picture.


Darryl Bailie wrote:
> When we specify raised tie trusses we specify that they sit on glide shoes.
> These let the trusses spread without inducing lateral loads on the top of
> the wall.
>
>
> >I am building a 20 foot wide barn with a gambrel roof. The trusses are
> > specially engineered so that no chords are needed (almost like a
> > scissor truss). This allows me to use the top of the barn as a loft.
> > But, I want to raise the height of the walls on which the trusses are
> > supported by 18 to 24 inches so that I have extra head room on the loft
> > level of the barn. Normally, the floor joists would stop the wall
> > spreading caused by the thrust of the roof, but since I am raising the
> > wall height, that is not the case anymore. Will I have a problem if I
> > don't add any more supports elsewhere (I am not about to use flying
> > buttresses on my barn). One potential solution I have is to use some
> > cross bracing from the top of the wall down inward to the floor joists
> > at an angle every so often along the wall, like:
> >
> > /
> > /
> > /
> > |\
> > | \
> > |----\---------
> > |
> >
> > That way I get the extra head room, and the braces won't be in the way.
> > Any thoughts?
> >


AppliancePartsPros.com, Inc.
Posted by Kickstart on August 23, 2006, 6:22 pm
I am using are made onsite and use plywood
> gussets at all of the intersections. A picture can be found here:
>
> http://www.barnplans.com/trusses.html
>
> It's the top picture, although you can't see the truss very well at
> that angle. Other pictures on the site show a better picture.

your link answers your question
"Engineered trusses are designed to transfer any lateral forces directly
downward onto the side walls. This eliminates the need for upstairs post
and beam supports"


kickstart



Posted by Darryl Bailie on August 25, 2006, 4:31 am
You must be able to get something like this in the States

http://www.alpeng.co.uk/publications/RoofTruss04.pdf#search=%22cullen%20truss%20clips%22

Darryl


>I don't know what glide shoes are and couldn't find a good explanation
> on the net...the trusses I am using are made onsite and use plywood
> gussets at all of the intersections. A picture can be found here:
>
> http://www.barnplans.com/trusses.html
>
> It's the top picture, although you can't see the truss very well at
> that angle. Other pictures on the site show a better picture.
>
>
> Darryl Bailie wrote:
>> When we specify raised tie trusses we specify that they sit on glide
>> shoes.
>> These let the trusses spread without inducing lateral loads on the top of
>> the wall.
>>
>>
>> >I am building a 20 foot wide barn with a gambrel roof. The trusses are
>> > specially engineered so that no chords are needed (almost like a
>> > scissor truss). This allows me to use the top of the barn as a loft.
>> > But, I want to raise the height of the walls on which the trusses are
>> > supported by 18 to 24 inches so that I have extra head room on the loft
>> > level of the barn. Normally, the floor joists would stop the wall
>> > spreading caused by the thrust of the roof, but since I am raising the
>> > wall height, that is not the case anymore. Will I have a problem if I
>> > don't add any more supports elsewhere (I am not about to use flying
>> > buttresses on my barn). One potential solution I have is to use some
>> > cross bracing from the top of the wall down inward to the floor joists
>> > at an angle every so often along the wall, like:
>> >
>> > /
>> > /
>> > /
>> > |\
>> > | \
>> > |----\---------
>> > |
>> >
>> > That way I get the extra head room, and the braces won't be in the way.
>> > Any thoughts?
>> >
>



Posted by RicodJour on August 25, 2006, 11:51 am
Darryl Bailie wrote:
> When we specify raised tie trusses we specify that they sit on glide shoes.
> These let the trusses spread without inducing lateral loads on the top of
> the wall.

The knee walls have to be able to carry the lateral loads from seismic
and wind loading. It's not just a question of the truss and truss
connections. Balloon framing is probably the easiest way to go.

R


Posted by Bob Morrison on August 23, 2006, 5:03 pm
In a previous post jbusboom@gmail.com wrote...
> I am building a 20 foot wide barn with a gambrel roof. The trusses are
> specially engineered so that no chords are needed (almost like a
> scissor truss). This allows me to use the top of the barn as a loft.
> But, I want to raise the height of the walls on which the trusses are
> supported by 18 to 24 inches so that I have extra head room on the loft
> level of the barn. Normally, the floor joists would stop the wall
> spreading caused by the thrust of the roof, but since I am raising the
> wall height, that is not the case anymore. Will I have a problem if I
> don't add any more supports elsewhere (I am not about to use flying
> buttresses on my barn). One potential solution I have is to use some
> cross bracing from the top of the wall down inward to the floor joists
> at an angle every so often along the wall, like:
>

One option is to balloon frame the walls to the truss support point.

If the walls are already in place then I suggest you contact a local
engineer for a solution. The building inspector, if he is alert, will
most likely require an engineered solution anyway.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
bob at rlmorrisonengr dot com

Page 2 of 2       << first < 1 2
Similar ThreadsPosted
Creating a gable roof out of a mansard roof July 20, 2006, 5:03 pm
Gable/Hip Roof Conversion from Hip roof October 1, 2006, 3:07 am
Wasps a problem for anyone? July 23, 2006, 4:59 pm
help with concrete problem pls November 20, 2006, 2:27 am
Problem with new house November 30, 2006, 10:56 am
Bachhoe Problem June 18, 2007, 1:12 pm
Submittal problem August 21, 2008, 10:35 pm
Problem Customer September 18, 2008, 8:24 pm
Is there any problem with having a narrower eave? July 16, 2006, 9:35 pm
foundation / settling problem October 4, 2006, 12:10 pm

Contact Us | Privacy Policy

XML SitemapXML Sitemap