Sunday 1 April 2012

Bridge Work Continues


HI Again
So I have done a bit more work to my bridge.
After I made the braces for my trusses I made a support to hold the top of the trusses together. I did this by folding one of my tubes in half and placing over the top of the truss.


Ignore the little pieces of masking tape in the photos. I placed those there to hold the trusses in place while I put the top support on. I removed it after (NO unauthorized materials allowed)
I then made the top cross beam to complete the top of the trusses. I used another paper tube and folded back the ends just enough to cross the span between the trusses.
Then I placed paper wraps around each joint. I also laminated paper around the top supports.
So now my glue needs to dry for a couple of days.
Next I plan on reinforcing most joints with toothpicks. I will need to visit Home Depot to get a drill bit small enough.
I am hoping to do a weight test once all the toothpicks are in place. My goal is to test at 28 lbs.
That was the weight of the original platform.
So how are you doing on your bridges.

Saturday 31 March 2012

The Bridge Competition

Hi Everyone
I started my bridge last night. I worked for 2.5 hours and got quite a bit done.
I thought I would send some pictures which may give you some ideas when you start your own bridge.
My ideas are not necessarily correct and are by no means the only way to do this but it may give you a starting point.
THe first thing that I did was to choose a design. I decided to use the Warren Truss System. I looked at the You Tube video of the world record and the winning design was a lot like this type so I decided to go with that.
 The next thing that I did was to make many tubes of rolled paper. I rolled my paper around a pencil ( actually two pencils taped together) so that they were pretty consistent in size.
I then used the tubes to make my bridge deck. I placed tubes beside each other in 5 long rows. I made sure that the joints were staggered so there would not be a weak point.

Then I made butt end joints and slip tubes at each joint to attach each tube. I then laminated the whole thing with sheets of paper. That completed the deck surface.

Next I had to start the trusses. I decided to fold some of my tubes so that they fit under the deck surface. THis way the deck would be suspended by the trusses.


I then drew out a  design for my bridge. My bridge is 57 cm long. I wanted three complete trusses so that means that each truss must be 19 cm long.  I marked on my deck where my trusses would be.
 So I think I am well on my way.  Obviously I have quite a bit more to do but my fingers are so stuck together with glue now that I need a break.
I have decided that my bridge will be called "Cooper's Crossing"
Will post more later
Faye