I recently inspected a 50+ year old Gothic-roof barn in southeast Oklahoma and found that it had an unusual ridge truss, which I have been told is an inverted queen post truss. The truss is constructed of dimensioned lumber and a steel cable acting as a bottom chord. Does anyone know of any other examples of this style truss used in barn construction? How common, or unusual, is it?

A la Swan Woodworks (not courtesy of, I took it without permission).



He's not able to tell about it, put here is a picture of it anyway. Pretty nice. If remember correctly he said something along the lines, "that design was taken from a french barn somewhere in France one would assume, minus cutting the post off and few other things." Hahaahha!

I've seen this technique used in old warehouse buildings that have been re-purposed. They wanted to remove some posts to open up the space below, so they cut off the posts about a foot below the beam, and added this type of steel arrangement to compensate. I imagine you could find this kind of structure in bridges as well? CB.

This technology may be derivative of a Paris to Versailles railroad bridge truss developed by a Belgian guy whose name I cannot find.

Read all about it here:

http://snurl.com/10q2vo [docs_google_com]

Hi Joel,

This approach can be found much closer to home for you at The Hancock Shaker Village where the centre lantern posts of the round barn are held up on tensioned rod. See :-

Hancock Round Barn

Equally for me "Cross House" which is next to the church in Bramley, Hamsphire, England also employs this type of technology to good advantage. See :-

Cross House roof

Regards

Ken Hume

New Energy Works project, Fort Montgomery visitor center.

Having done some research now on inverted queen post trusses, they are similar to the truss in the barn, but not exactly. The center section of the truss is a queen post truss, with two symetrical posts, but there are two additional, unbraced, slightly shorter posts flanking the two middle posts (queen with handmaidens?), so the steel cable bottom chord is in five distinct sections, not three like a true inverted queen post truss.

Wish I had a URL to post a sketch to. Result is perhaps somewhere between an inverted queen post truss and and inverted bowstring truss, with a horizontal top chord.

Go to photobucket of flikr and make an account, it's free and real easy, and then please upload the picture. They will give you a handy little box with the URL for a direct link. Then you will have an account for future pic uplaods, and believe me you will use it!

This of course is assuming you have pictures in digital form

Here's a link to a drawing

[img]http://flic.kr/p/8u6RJ9[/img]

Links to photos

[img]http://flic.kr/p/8u6Sms[/img]

[img]http://flic.kr/p/8u6SaW[/img]

[img]http://flic.kr/p/8u3L7P[/img]

[img]http://flic.kr/p/8u6SxJ[/img]

Hi OKarch,

This really doesn't look like a very clever arrangement.

The purlins are buckling and have now deformed badly.

Was this barn originally fitted with a lantern ?

Regards

Ken Hume

Must be the roof skin holding it all together.

Tim

Tricky to get Flckr images to show up inline!
Ridge looks too small to take the compression load when the bottom chord goes into compression. And it looks like it was pieced together - another potential weak spot.

Do you know any more history on the structure? Looks like a quonset hut?

Ken, where is all that metal in the Hancock barn, in the basement/manure trench? I've never seen it before. I'm about 20 minutes away, and a volunteer there, I might have to go check it out.

Hi Dave,

Its some time since I visited this barn - nearly 20 years ago ! and so you might well be correct. If you revisit then please try and get a good digi pic of this feature since my version is made with colour film now more than a little deteriorated. I think that what I previously described as the lantern should probably more accurately be descrbed as a vast centrally positioned haymow from which the cows were fed on a floor around the perimeter of the barn. I seem to recall that the metal support rods were underneath and supported the posts between the cow floor and hay mow which logically must have been above the manure trench. It would be good if you could tell us how these rods are anchored at both ends and how these anchor points were kept stable as construction of the barn took place.

Regards

Ken Hume

Ken,

I'll see if I can make it up to the Village tomorrow. I'll have to check on access to that part of the barn, I know it's not open to the public, but I can usually get into the attics and basements if I ask.

Ken

Looks exactly like a quonset hut.

Barn has two sheet metal cupola vents.

Really don't know much about the history. Owner says it was there when her father bought the place in 1959.

I agree the top chord is woefully under-designed. And poorly constructed.

So far no one has said that they've seen anything like this before, so I'm assuming this is unique.

I suspect it's unique for good reason...

What are the owner's intentions for this structure, I wonder?

I miss derek. Cool shot!