1000 years and a wooden bridge still stands.

It sure surprises me how technology from 1000 years ago was advanced enough to outperform current techniques. You can use the search term "Chinese wooden arch bridge" and you will easily find references to these amazing structures. My resources are sparse on this incredibly durable technique of forming load bearing wooden arches. Any additional resources on these construction techniques would be greatly appreciated. I am looking at the potential of employing these as a complementary construction technique for earth sheltered designed homes, predominantly as a roof structure.

Hello Amedean, et al,

I was almost part of the project that you just referenced on this topic. This subject is one that I have studied and practiced for over 35 years, and know most in North America familiar with it. Its technology goes back further than a thousand years and perhaps as far as the Shang Dynasties.

If I may be of service in answer your questions, or anything else regarding this subject, please let me know. I would love to co facilitate a writhing project here at Permies on any "real world" applications you may in the future pursue. In the interim, it will help you to learn to do advanced searches in Google, and also become very familiar with search in Chinese, Korean and Japanese kanji (script or calligraphy) on this subject.

Regards,

j

Jay C. White Cloud wrote:Hello Amedean, et al,

I was almost part of the project that you just referenced on this topic. This subject is one that I have studied and practiced for over 35 years, and know most in North America familiar with it. Its technology goes back further than a thousand years and perhaps as far as the Shang Dynasties.

If I may be of service in answer your questions, or anything else regarding this subject, please let me know. I would love to co facilitate a writhing project here at Permies on any "real world" applications you may in the future pursue. In the interim, it will help you to learn to do advanced searches in Google, and also become very familiar with search in Chinese, Korean and Japanese kanji (script or calligraphy) on this subject.

Regards,

j

Jay!!! Where have you been lately? Well, its always good to here your incite on all things wooden, lol!

Okay, so question......where can I get any books in English that provide the engineering incite? Also since your my go-to guy for all things wood, I imagine you have had thoughts on employing these structures so what if any were your ideas?

Hi Amedean,

I have been around, just busy....

......where can I get any books in English that provide the engineering incite?

... I imagine you have had thoughts on employing these structures so what if any were your ideas?

Well first learn to do advanced searching with computers and doing search in 中国, 한국, and 日本人...

Well, actually there really aren't any engineering books on it per se...and several folks have nagged at me about that, yet there is plenty of engineering books and the math is the math...doesn't matter what you apply it to really. You must also remember that much of a PE job comes from actuary tables based on statistical analysis of things like modules rupture, compression, tension, elongation...blah, blah, blah.....the "key" word in that was "statistics." Which is why I have worked professionally with the same PE group and senior primary in the firm (Ben) for over twenty years...you got to have a PE that know traditional stuff like timber framing....Not many of those around.

So on most projects is still think of myself as a Senior Apprentice 大工, and just follow the lead of my elders...in other words, a lot of copping and then making models to check this as valid. On that not, you asked about my ideas...too many...but for you...you need to make drawings and then scale models. It's the tradition to do so anyway. Once you make a few models of these "Moon" or "Circle" bridges, you will make the complicated seam much eaiser...which brilliant things always are.

Here is a link to a retired friend of my that is probably one of the leading "English" speaking authorities on all thing Chinese Bridge related (even wrote a "picture book" on it called "Chinese Bridge.") His name is Ronald G. Knapp and if it is known, he either knows it, has seen it, or knows who knows it...

As for books...perhaps hundreds...maybe...and few no technical one (some in development) in English...a couple in German I think...

Regards,

j

Amedean Messan wrote: I am looking at the potential of employing these as a complementary construction technique for earth sheltered designed homes, predominantly as a roof structure.

It would seem to me that the massive stone abutments would be necessary to support the vertical members and thus the downward force of the beam weaving. This would probably make the technique impractical for house design unless your outer earthworks could be made structural to hold this force. Not to say that that's impossible, but seems like it might be more work / expense than would make this technique worthwhile. That said, with the snowloads of certain areas, when combined with the weight of the structure, and soil, it maybe worth while to create such a powerful structure. It seems like a beautiful and artful technique with great structural engineering. It would be really interesting to see the history of the technique and who first created such a thing. Quite amazing. I would love to see the blueprints of the one that was built in this video.

Hello All,

R. Knapp, professor emeritus at SUNY may well have several blueprints or knows who does...

Creating a model from just the provided graphics online is more than plausible as well.

I would also note that for the application-augmentation of this timber design into domestic architecture may only need partial (perhaps not at all) the reinforcement and strengthening of the foundation area if a "tension system" instead was employed. I can quickly think of several that could possibly work. I would also not that there are "corbeling" methods for Chinese bridges that also have domestic architecture possibilities as well. The corbelled roofs of the Native Dine, and several other cultures also present strong merit.

Regards,

j

Jay

I'm wondering about the tension systems that you mention. Do you mean, in a house, constructing a timberframed sill of locked together members which resist outward force together from the bottom? Or are you referring to purlins (with dovetails) or beams (with deep tenons) which connect the posts below the weaving, or connect the woven beams from one side to the other? Just trying to get a picture of it in my mind. I have some basic timberframing behind me, but have virtually no experience compared to you. I guess I am more meaning outward force that the stone bridge abutments are supporting, not necessarily the downward force as in my previous post. I do like the corbelled Dene hogan roof's that I believe you are referring to. They are incredibly strong and much simpler than these bridge structures.

Do you mean, in a house, constructing a timberframed sill of locked together members which resist outward force together from the bottom?

Bingo....you got it!

Or are you referring to purlins (with dovetails) or beams (with deep tenons) which connect the posts below the weaving, or connect the woven beams from one side to the other?

This wouldn't achieve anything...and could actually weaken the system just as the "alleged" collar tie in many roofs which is to close to the peak. If a collar tie, or any similar tie, is not at the foot of a rafter (or minimum within close proximity) actual does nothing for a roof system and will facilitate failure. Structural its called "breaking the back," as it creates a "hinge effect" in wind event working un-equaling on one roof diaphragm compared to the other.

I guess I am more meaning outward force that the stone bridge abutments are supporting, not necessarily the downward force as in my previous post.

Out or down in a domestic configuration these could be dealt with a tension solution instead of a compression one...

I do like the corbelled Dene hogan roof's that I believe you are referring to. They are incredibly strong and much simpler than these bridge structures.

Exactly, and depending on the design of the structure could be above or below grade architecture. The Chinese corbelled bridges and the Dine system working in concert with one another would also have very strong merit.

Regards,

j

I found a PBS special on these wooden arch bridges which I thought I should share. Best english film I have found on the subject. If you fast foward to 50:30 then you can see that 4 tons of water buffalo had no effect on the structure. This may be evidence for a good solution to partially subterranean roof structure or green roof.

Hi Amedean,

Thanks for posting this...these are some of the same folks I had referenced earlier. Some of these are true arch bridges, while others are corbelled bridges.

Regards,

j