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Picture of Simple Japanese Bridge
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This is a very small and simple bridge designed to cross a pond in Japanese styled garden. 
On a bridge of this scale I couldn't add handrails or really any details that you may get on a larger bridge.

I also won't go into too much detail because, with the possible exception of the beam bending, this is just as simple as it looks.

The cost of the timber was £20 and it took me about 3 afternoons to build and install.

Enjoy
 
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Step 1: Materials

Picture of Materials
Design
The size and design of the bridge will have to fit the garden, this is a small garden so I made the bridge as slender as possible so as not to overpower its surroundings.

Materials
I used sawn treated pine, very rough cut pieces but they're cheap and treated to make them more durable.

- 19x32x2400mm, 8 pieces, these will form the curved beams, I only need 2 but it's good to have lots of spares

- 19x100x2400mm, 3 pieces, I sawed these planks in half to give me 50mm width planks, this was mainly to save money.
      alternately just buy 19x50mm planks.

- Wood Glue, I recommend Evo Stick because the strength of the curved beams will depend a lot on the glue.

- Wood Screws, get exterior grade to ensure they don't rust away.

- Plastic Stakes, large plastic stakes to secure the bridge to the ground

Tools
This depends entirely on how good a finish you want to put on your bridge.

Basic Tools: Timber Saw, Drill, Mallet.

Finishing Tools: Plane, Power Sander / Sand Paper, Router.

Step 2: Laminating Beams

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First you need to make the jig that will hold the beams as they set. Cut yourself a bunch of stakes from the smaller timber planks.

Using a mallet hammer these into the ground as shown so that you can hold your beams in a curve between them. 

Each point uses two stakes. One straight down and one at a 45° angle to brace it.

Once you have set out your jig and tested it with a piece to see that you are happy with the curve you are ready to laminate.


Note: Pick your pieces carefully for this try to get a piece free of knots or weak spots, especially make sure there are no knots at the centre as this is where the greatest tension is placed during bending.


Place your first piece into the jig and then proceed to add a good layer of glue to your second piece. Starting at one of the ends, carefully align your second piece on top of the first and gently bend it round and secure it behind the stake at the other end.

Once the two pieces are glued and in the jig, make sure they are aligned and then add clamps in any places where the two aren't sitting directly next to each other.

Add screws along the length of the beam, every 200-300mm. make sure to drill pilot holes so you don't crack the wood.

Give the first beam about and hour for the glue to dry, then remove the clamps and you can repeat the process to create the second beam right on top, this ensures both beams have an identical curve.

I used a bin bag to ensure I didn't glue one beam to the other.

Leave the two beams for 24 hours to let the glue properly set, then you can remove both from the jig.

Step 3: Finishing Beams

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Most of this step is optional, I used rough cuts of wood so I wanted to tidy them up a bit, you can buy pre-planed wood, but this is expensive.

I used a plane to even out the beams where they weren't properly aligned.

I then filled in any gaps and knots with wood filler.

After that I sanded the whole thing using 40 grit paper.

Step 4: Cutting and Finishing Planks

Picture of Cutting and Finishing Planks
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This step is pretty self explanatory. 

First I planed and sanded the larger boards I bought.
Then I cut them in half lengthways to give me 50mm boards.
I cut these into 400mm lengths (the final width of my bridge) and then tidied them up a bit.

I also used a Dremel with a router attachment to add a 45° chamfered edge to all the boards to make them look a bit neater.

My bridge ended up needing 23 in all, always make a few extra in case you somehow mess one up.

Step 5: Completing the Frame

Picture of Completing the Frame
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Again this step is pretty easy.

Mark and cut the ends of your curved beams so that they will sit flat on the ground.

Then screw two beams to some rough planks to make a square frame. 

Each end plank has two holes drilled in it which will have plastic stakes pinning the whole frame down.

Step 6: Installation

Take your frame and set it down where you want to install your bridge. Take your time getting the placement right because it is a bit of a hassle to move it later.

I used 4 large plastic garden stakes to pin my frame in place.

Once this is done you can begin to put down your planks. Make sure the plank is centred and square with the rest of the frame, once the position is right drill through the plank and into the frame. 

Once the two holes are drilled lift the plank back up, add a small amount of glue to where the plank meets the frame and screw the plank in place.

Continue to add planks in this fashion. I used two pencils to make sure that the gaps were even.

This process can be a bit tedious but once you get into a rhythm then you'll soon have it all screwed in place.

Note: you may find that the screws in the curved beams are in the way of where you want to place a plank, In this case you can remove the beam screws.
You must also be aware that towards the end of your bridge you may have to adjust your gap size to make sure that you don't have any frame peeking out.


Weatherproofing, I have left my timber bare, this way it will weather to a nice silver colour (it clashes a bit at the moment) you can wax or stain wood to protect it against the elements but I prefer not too.

Finished, you may notice a bit of bounce in the frame, but this should settle as the timber weathers. I'll try to update when the garden in finished and the bridge has weathered a bit.
racoontnn1 year ago
This is exactly what I was looking for a long time for his garden, which did trickle. Thank you.
AndyDap3 years ago
Thanks heaps for a great instructable and a great idea.
I built one pretty much exactly as you've described but scaled it up. Mine is 3m long and about 2m wide. I added another laminated beam and everything is 25mm thick, rather than 19mm.
Hope you like the pickies. As you can see, it takes my ride-on without a problem.
Thanks again.
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Mutantflame3 years ago
It looks good, but won't the wood warp/bend if it gets wet?
madmanmoe64 (author)  Mutantflame3 years ago
I'm expecting the whole thing to settle a bit as it ages, but because I have laminated two bits together and pinned the whole thing down, hopefully it won't warp.
eedrin3 years ago
Thanks so much - the little bridge looks great! And, I love your tiny pond :)
Mupton1013 years ago
Very nice. I'm going to give it a try.
dimtick3 years ago
Nice instructable.
Your bridge is sitting on the ground and is very volnerarable to wood rot. there are many easy ways to help with this.
I recommend digging out on either end and filling with gravel so that water will drain away from the bridge ends into the stream. Put a rock or paver, under each corner to raise the ends just a couple inch's off the ground. this will also help with drainage and wood rot.
you've built out of pine which is going to deteriorate after a few years. if you can I would rebuild the arch frame out of cedar. it would be good to do the planks as well but it's ok to keep those pine. it's easy enough to replace the planks but the arch is harder.
Your arch beams are narrow so if you want a cleaner look you could screw the planks in from underneath.
donvee dimtick3 years ago
he stated the he used treated lumber
Even treated wood will rot out prematurely if it is lying against the ground. I have had it happen to me on more than one occasion. Better to put a few inches of pea gravel under it.
Absolutely! This is a very common misconception! Treated lumber is designed to be proof against insect attack, and is only minimally resistant to rot. There are better materials to use that will survive occasional wetting, or sitting in water. How do I know this? I have lived in a condo for the past 33 years, and have watched as the management morons replace 126 decks (made entirely of treated lumber) every 5 to 6 years. After the contractors tear out the old deck, and drop the remains in the dumpster, it is easy to see that the failures were EXCLUSIVELY due to rot caused by water contact! (The definition of insanity is to perform the same act repeatedly, always expecting a different outcome!) My 25 or so years of experience as a builder notwithstanding, the condo management refuses to use different (read more expensive) materials, and routinely assesses additional fees to cover the cost of this "unexpected" failure!!!
How about recycled pastic lumber?
the recycled plastic lumber will work for the cross pieces that directly contact the ground.
I wouldn't use it for the planks because it can get slippery.
madmanmoe64 (author)  dimtick3 years ago
I had planned to use Western Red Cedar, but the place I was going to use ran out of stock and I needed to finish the project quickly.

I intended the base bits to be sacrificial so the beams aren't sitting on the soil but Gravel is going down on the far side of the bridge anyway so I may take your advice and put some under each edge of the bridge.
serge3 years ago
Very nice tutorial. The finishing look is very nice. I bookmark this for future use !
cogni3 years ago
Very elegant! I like the gentle slope of the arch.
Dimtick is right about wood rot. In general the British climate is not going to treat your bridge very well. For the time spent on it it would be worth it to buy rot-resistant wood and to weather proof it. I need one of these bridges to go over a small stream in our New Zealand garden. Nothing wooden lasts there very long outside. It is even rainier than Britain. Our 5 year old weather-resistant weather-proofed wooden patio table looks 100 years old. Not in a good way.
madmanmoe64 (author)  cogni3 years ago
I would have loved to have done this properly, but didn't have the time or money, when it collapses in 2 years I can do it right.
oakback3 years ago
Great instructable! I also love that whole space you have there. I have a large yard, but seeing that makes me want to wall-off a portion of it and make a cozy space like that! Did you do all that (deck, water feature, etc.) yourself?
madmanmoe64 (author)  oakback3 years ago
Deck was there already, My sister (whose garden it is) has done all the rest, the pond was a bit tricky at first but is looking good now.
samchamb3 years ago
Nice job . I have noticed that tile batten can have some nasty knots , I prosume that you chose to lamminate 2 lenths so bending was possable and a weak knotty area in one lenth would be renforced by its mate .
madmanmoe64 (author)  samchamb3 years ago
Yup, If I were spanning any more than a meter I would've laminated 3 or more.
geppetto4253 years ago
Great bridge. Might be better to have the grain running vertical on the long support arms so it would be stronger. I made one like this a long time ago, cut arches out of treated 2 x 12's.
Well done. I was surprised to see how delicate the bridge appears with you in the photo, which suits the garden's scale nicely..

I designed a similar bridge for a projects book published in 1994. It has a taller arch and the arched timbers are secured with three cross-beams. Materials were 1.5" Western Red Cedar and galvanized screws if I recall, I gave most of my book projects away once completed.

Thanks for the Ible!
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