How To Build A Simple Wood Bridge - Leonardo Da Vinci Style
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- Опубліковано 22 гру 2019
- www.homebuildingandrepairs.com
Here's another great idea from Leonardo da Vinci or at least it seems like he's the individual gets the credit for this architectural design and engineering wonder. A simple bridge that could be built out of a variety of different size boards or even tree branches. Watch the video and if you're anything like me you will be amazed at how building a bridge can be so simple.
Your video was very helpful. I used 2x6x10’s to span 25’ over a creek. Probably should have used 2x6x8’s. Would recommend making the cross pieces extend a couple of feet each side to brace the railing. Mine is 4’ wide. 3’ might have worked. The arched design raises the bridge over our creek so it shouldn’t wash away next heavy rain.
Thanks for the info!
I need about the same length of bridge for a creek. 4' wide sounds good as it's only one cut to make 2 treads out of an 8'er. I was leaning towards using 2x10's 12 to 16 foot long. (Was going to draw it out to see if the shorter length would make too high an arch). If I may ask you some questions, you're first hand experience might be helpful as some things I haven't found info on:
1: Do you find the 2x6's for the frame to be bouncy with that length of span?
2: Did you notch the length-wise boards where they came to rest on the cross boards?
3: Did you use 2x6 lumber for everything, or just the spanning boards and some other 2x lumber for the cross boards and treads?
4: How may boards did it take to build? (2x10's? and/or other 2x lumber if used?)
Really appreciate any info you can provide. The crossing is on a public trail, along the boarder of my property. I use it regularly as the creek divides my land in two and lots of elderly locals use the trail for hiking and dog walks. I'll be buying the wood and doing all the work on my own, so this style of building in pieces would be ideal. To this point, I've been planning to use a big Fir tree that fell on my property, close to the bridge location. The plan was to free hand mill 26' long sections from it, roughly 3-4" thick, and 16" wide. BUT.... like I said, I'm all on my own, quite a ways from my house and downhill. So I'm having to consider the weight of two big beams like that, the amount of chainsaw work, danger factors, etc. I'm not in my 40's anymore! ;D. Plus, if I use lumber, I can pre-build and number the pieces using pressure treated wood and apply extra protective finish. The creek can be crossed in the summer, but is difficult due to rocks, and I'd hate for seniors to get hurt and stuck there alone, and with bears and cougars about.
Anyway, I'm babbling..... :D
Thanks very much again, for any info or advise you can give!
Regards,
Bert
Here's a link to a modified wood bridge design that might be helpful. ua-cam.com/video/QmMeNJ5h4gE/v-deo.html
Amazingly simple and elegant.
I like it to.
Hi
Hi daddy uh chill
As always your video was a godsend man. You do good work👍 keep on keeping on brother!
I appreciate that!
Like it flexes.. Thanks Dog!!
Any time
Exactly what I'm looking for to have an arched ramp up a few steps to lessen the upper angle and prevent (light) motorcycle parts from dragging, thinking 4-6' boards will get me there.
Look goods
how much weight can a 14 foot span with 2x4s handle though - i was thinking of making a bridge over a creek near our house with 2x12s bc i don't know how the math works and id rather over than under do it - any insight?
We'd need to answer several questions before we could answer your question at the end.
What grade of dimension lumber do you plan to use? Will it be treated lumber? Are you able to get them in 14 ft lengths or will you need to join shorter pieces?
Look up rainbow bridges canada.. They have some pretty good looking bridges
But are they strong?
@@andrewprahst2529 Yes.
@@HolyCrudCakes Hi
Look up China Song Dynasty Qingming Rainbow Bridge, pre-dates Da Vinci's design by about 500 years. Theirs were more practical, and built in the thousands all over ancient China, some existing till this day, Da Vinci's design was too minimal or simple, and like most of his designs was never built during his lifetime. A good example of engineer vs architect meme imo.
@@karthur3421 hey thanks for the reply. I will look it up right now. Always looking for good information on this stuff.
Looks a bit different than those i build. (Maybe cus you used screws cus the leonardo bridge can actually hold itself without any extra planks
Would it hold two cars over it
If it was build different or with stronger materials, maybe
Hi
I wanna build a house using only gravity fit. That would involve some more advanced maths tho.
Friction fit*
@@someting9205 Hi
While the design is quite clever, I wonder what an engineer would say about the loading for common dimensional lumber versus length. Seeing as each 12ft section is divided in half (6ft) for loading I would guess this can only hold a few hundred pounds per section without additional bracing. We're talking a safe load, so not to the breaking point of several fat people bouncing around. We also have to consider that a portion of the load on each section is transferred to the other sections, which will require a little math to make sure things are not overloaded in the next section.
Good question for an engineer.
do you know the explanation?
@@telmanfeyziyev8040 ... I understand the concept enough to know there is both tension and compression of materials involved, if you utilize a proper headwall on each end. If you need it to carry more load you can add more of the long members in the center section and sturdier cross members. (doubled up?) The idea here is some weight from one section is transferred to the next section. I would guess it's a decreasing percentage or a ratio progressing to each section as you move away from the loaded area. It would be very strong for the amount of material involved.
I am an engineer; a bridge engineer.
You can make a suitable DaVinci bridge, but it takes more lumber than shown here. I would probably use 2x6 as the smallest thing I would consider, and I'd have several "ribs", where he is only showing two.
The "scissors" approach has been known and I have been studying it, but it isn't easy to compute the critical stresses.
I am planning to build several footbridges (which is why I am viewing these videos this evening) with my scouts, but they will be more substantial than this illustration implies.
If you build a bridge, you may have to construct a competent handrail to meet code requirements.
Good luck.
@@eddarby469 ... with a little forethought, the handrail could add strength to the bridge itself.