User:NathanMinnick58/ENES-100/project 2

Research
There are five different types of bridge designs.

Beam Bridge- is the easy bridge to design because they are made of piers that support the horizontal beams. The strength is determined by the roadway and by adding additional piers increases the strength of Beam Bridge. Compression acts on the top of the roadway and the beam of the bridge and though the piers. Tension is pulling apart the underside of the roadway as the loads passes over the bridge is pressing down

Pros: these bridge are easy to build, inexpensive and is used in urban and rural area.

Cons: these bridge’s span between the piers are limited to a certain length, large ships and boats cannot pass underneath and they do not have an interesting appearance.

Arch bridge- the arch uses semicircle design that can reduce the compression forces throughout the structure of the bridge. If the semicircle of the arch is greater than there is a greater the effect of the tension on the underside of the bridge. The arch bridge strength is determine by the shape of the arch.

Pros: is that the bridge is very strong and can use many different materials to build.

Cons: the design is limited to certain sites and can be expensive.

Truss bridge-are made up of triangle that holds up the roadway and is set on two piers for support. Truss bridge are very strong and are support heavy loads. The triangle angle are used because they are rigid and are stable. Compression acts on the upper horizontal members of the truss structure and in the piers that support the bridge. Tension acts on the bottom horizontal members. The angular members shares both of the force.

Pros: very strong used for a draw bridge or used for railroad trains.

Cons: difficult to build and require high maintenance. Are different to widen the bridge.

Suspension bridge- are strong bridge that can span for long distances. They require large amount of materials and takes a long time to build. They are usually located near harbors. Suspensions bridges commonly have cable that stretch from two towers and are attached to each end of the bridge. The smaller cables are attached to the main cable to the roadway. The compression in the bridge is carried through the cables to the two towers. Tension is always acting on the cable because the roadway is stretching them.

Pros: can span long distances, can allow large ships and bats to travel underneath.

Cons: Expensive and requires a long time to build. Requires a large amount of material.

Cable stayed bridge- are similar to Suspension bridges but are cheaper in cost and materials. These bridges have one or more towers that have cable attached to the roadway. The compression is in the cables that are attached to the roadway and transfer to the towers. The tension is always located in the cables because the roadway is stretching them.

Pros: can span medium distance of about 500-2800 feet, are less expensive and faster to build than suspension bridge.

Cons: are typically more expensive than the other type of bridges.

| Draw Bridge design

|Basic types of truss bridges or other bridges

| pdf file of an explanation of the 5 common bridges

|Truss Bridge design

Design
The group decides to use a truss design for a draw bridge. that opens in the middle.

Materials

Truss members
 * 3 ft. x 1/4 in. Basswood Square Dowel
 * 3/8 in. x 3/8 in. Poplar Square Dowel
 * 3 ft. x 1/2 in. American Basswood Square Dowel

The roadway
 * Poplar Hobby Board 1/4 in. x 4 in. x 4 ft.

The hydraulic system
 * 2 VvW Large Plastic 100ml Syringe +120cm (47in) handy plastic tubing
 * 2 Plastic 100ml Syringe

The servo motors.

Week 1
I complete research on the different type of bridges to develop ideas for the next project. The group has decide to processed with the truss design to construct a draw bridge. All of the research that I have make is located above

Week 2
I design a truss bridge in autodesk inventor. The is an assembly drawing with two parts the truss bridge and the holder. First made a sketched of half of the bridge and was able to put constraints on the bridge so that it was connected with the holder. Then I mirror the whole assembly to make a complete bridge. I was able to make the bridge move because i used a constraint function on the parts and using the inventor studio in the Autodesk. I was able to animate the constraint i put on the bridge so that hte bridge can open and closed at 45 degrees. | A video of the truss draw bridge that I design.

I also make a simple bridge in openSCAD, these are the code that I used to design the bridge.

cube(size =[10,21,1],center=true);

translate([4.5,0,1])

cube(size =[1,21,1],center=true);

translate([-4.5,0,1])

cube(size =[1,21,1],center=true);

union{ translate ([4.5,9,-3])

cylinder(h=5, r=1, center=true, $fn=100);

translate ([-4.5,9,-3])

cylinder(h=5, r=1, center=true, $fn=100);

translate ([-5.5,9,-1.5]) rotate ([90,0,90]) cylinder (r=1, h=11,$fn=100);

}

union{

translate ([4.5,-9,-3])

cylinder(h=5, r=1, center=true, $fn=100);

translate ([-4.5,-9,-3])

cylinder(h=5, r=1, center=true, $fn=100);

translate ([-5.5,-9,-1.5])

rotate ([90,0,90]) cylinder (r=1, h=11,$fn=100);

}

Week 3
The bill of materials for the project will include the prices of the wood for the base and the sides of the truss. The syringes and plastic tubing for the hydraulic system. Tools glue. Bill of Materials