Double Arched DAR Pedestrian Bridge

My name is Jacob Nord, I am 15 years old and I live in Klamath Falls, Oregon. I am in 9th grade and home-schooled.

I've been using Tinkercad for a while and it's been very useful to build different projects and ideas so I have some experience with how it works.

I've read all of the 'official rules' and I've tried to incorporate as many ideas that will go with the rules.

I've always have wanted to fly a plane, and flight school is very expensive, so when I saw this contest I got excited and built a bridge hoping there might be a chance of winning so I can pursue my dream of flying.

If I had a 3D printer I would have printed out my design and made a small model bridge with a landscape for this contest, but I can't afford a 3D printer, so I used Tinkercad for the demonstration.

Down below I created a video demonstration of the bridge so please check that out.

• Tinkercad

• $100,000+ 3D printing robot with GPS and Al technology ( If you so happen to have one )
• Plastic pellets- for printing
• Concrete - for the foundation

There are some supplies that may vary...

On my first Instructable post, I had explained how that when I saw the Dar bridge that Autodesk has put up as an example, my idea was to just join the two bridges together and call it good. But I could see that people take these contests seriously, so I took some more time in what I was going to work on and added as many details as I could think of.

After building a single arched bridge, and thinking of the problems that are created if it is lengthened, I decided to make a Dar-ble (double) arched bridge. With this concept, of building this bridge, it could be made as long as it needs to be on a flatter surface, such as; over a wide sink-hole or over a shallow river, creek or pond.

• The nice thing about this design is that it can be either lengthened shortened and/or widened on a Cad program and then 3D printed in life-size form (the individual bridge sections, for this specific design) and will still be plenty strong. This will make it easy to fit the bridge into any location were it needs to fit. Other bridge designs usually require lots of engineering for a bridge to fit into a planned location. (In the picture above, the right arch was shortened)
• The column in the middle can be printed into place depending on how much weight is predicted or depending on how long it is planned to be built.
• I didn't add any ramps or steps to the design because the terrain will affect what design of ramp or steps l add.

I decided to put this in the same landscape/background to give you one idea of how this bridge could be placed, but I didn't add too much detail on the landscape since l'm not entering for a landscaping contest:-)

For this specific design, it seems to fit a little better in the layout than the single arched bridge.

The middle foundation block is not supposed to be floating - I had a pile of dirt under it but due to some technical difficulties, it is not there for some reason...

The landscape is NOT based off of or scale to anything.

I wanted to incorporate "made with Autodesk Software" on the 'threshold' on both sides of the bridge so everyone knows how the design was made.

Here in southern Oregon there has been a harsh drought, and the farmers, the local Tribal members, and environmentalists, have been fighting over what little water there is in Klamath Lake. This is where farmers get their water. Finally after many years of little rain and water, this year we had lots of rain and the lake is now full and the river and ditches are full also, and everyone has water. Therefore I think this bridge would be a great way to "bridge gaps", even if in the future there is a drought.

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There is a park/recreation area to the south east of town that I think would be a good spot for this double arched bridge(or could be a triple arched if need be) . People go out there to go mountain biking, hiking, fishing and picnicking. There would be plenty of people to use the bridge. There is also going to be a new subdivision on the east side of the river. Having a bridge here will allow people to go have fun in this park, on the other side without having to drive around the river to a bridge upstream.

The idea of having a robot print it's way across a ditch or creek can be very efficient and quick when things go right. With the right equipment and ideas, it will make it even easier to print a bridge in the elements.

Required steps/supplies to accomplish the build efficiently:

• A vehicle to transport the robot and the materials needed to the job site.
• The vehicle should have a crane/boom to place the foundation or 'pile' to the right location. The robot then has a good spot to print off of.
• Equip the vehicle to be able to provide some concrete to pour into the plastic hollow foundation blocks.
• Have the vehicle to be able to re-charge the robot at any time and quickly on-site. Also the vehicle can carry additional tools for the workers to use to make different adjustments for the robot or the ground around the bridge location.
• Construct the pre-cast hollow foundation blocks to have magnets imbedded in the plastic were the robot will calibrate. This will enable the robot to know exactly where to start printing, thus allowing the robot to print the bridge very accurately.
• A mechanical grabber on the robot addition to the printing nozzle will improve productivity.

The list above just gives some ideas that could make 3D printing a bridge easier, quicker and more accurate.

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I also have some different ideas of elements that could be printed into the bridge.

• Carbon fiber string could be printed into the layers of the bridge adding extra strength to X,Y,Z axis.
• Mosquito repellent could be mixed into the plastic as it is being printed. (The oils that are in mosquito bracelets)
• Paint or dyes could be added to the the plastic to make different colors, patterns and themes.
• UV protective coating could be sprayed onto the bridge to prevent sun exposure on the plastic.

The ideas listed above are optional depending on where the bridge would be built, or how durable it needs to be.

The robot will need a GPS system, to allow the robot to print the bridge very straight and accurately. When the robot takes a break to go re-charge or re-fill on plastics the GPS system will allow it to resume from the right location

Having a GPS system programed into the robot will enable accomplishing the project quicker.

Here in the Klamath Basin the mosquitos and midges get very thick and it becomes very hard to go out and enjoy the outdoors.

So l thought of how mosquito bracelets work, and looked into it. Natural oils are added into the plastics of the bracelets, and since the bridge is made of plastic, these oils could be incorporated into the material.

Because these bugs love the river where the bridge would be, the bridge would keep them away so that people could use the bridge and enjoy the outdoors without pesky bugs at the bridge.

Designing a bridge that can span a long way without support, can create some problems.

The nice thing about 3D printing is that before the object is printed, things can be added, modified or changed. So that being said, a sleeve could be added to the middle of the bridge, and with a mechanical grabber the robot could slide a metal pillar/piling through the sleeve to a surface below to give it temporary strength until the robot has printed its way to the other side. The pillar/piling could be taken out, or the robot could print around it to give it a unique look. (In this picture, the pillar on the first arch was taken out, the second arch has the pillar because, it has not been printed all the way yet.)

After the robot is done printing and the bridge is done, the manual labor is next. The bridge up to this point has only been printed/attached onto the foundation blocks. Bolts will have to be synched down tight to finish the securing process.

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The metal railing will have to be bolted down manually.

This makes the bridge ready for people to start to use.

Then after a lot of steps... here we are with the finished product!

I think this would be a good bridge for our community because as l said before, there has been a lot of tension here in the Basin, because there has been no water. But since there is plenty of water for everyone now this year, this bridge would be a good way to "bridge gaps", even for in the future.

This town is not a growing town, but a unique bridge would be a a good way to put Klamath Falls on the map.

I have really enjoyed the building process of this project. It seemed that it took a long time to build, and get to this point.

There was lots of videoing involved, editing the videos, taking screenshots, editing again, and writing this Instructable and editing that. So there was a lot of work put into this.

I'm not the best at writing, but I hope I have explained this bridge concept well enough to you.

You may see me put a few more bridge concepts/variations of this bridge or, other types of bridges in a few days.

I hope that this bridge will qualify for the contest and I wish good luck to fellow contestants, and happy building (-:

Please check out my other bridge entry with the link(s) below:

https://www.instructables.com/Dar-Pedestrian-Bridge/

https://www.instructables.com/Dar-Pedestrian-Bridge-Inverted-Version/