Description of Bridge My bridge is like an

Description of Bridge : My bridge is like an “A” truss bridge, with heavy duty beams for cross supports and I added vertical members, There is strength in numbers, so I took multiple pieces of spaghetti and glued them together to form a round beam. To glue them together I would do the ends first and roll them until the glue dried and then wrap the glue around at multiple points to keep them together. I took eight pieces and made three lower cords, I then used four pieces for the vertical members and end posts. The deck sits on three sets of floor beams and the sway bracing are single strands. By definition my bridge is made up of what I tried to do is six equal panels. I tried to represent diagonal connections using the glue at each connection. I am making a device that sits across the center of my bridge and hangs underneath to add the weight to measure the strength of the bridge.

I made the 3 lower cords big more like seen on a beam bridge

I set up my bridge supports 6 inches apart. For my testing apparatus , I made a basket hanging from two beams that went completely across the bridge, I then made paddle for the reading to be taken from.

Prediction of Failure : Looking at the bridge I believe the end posts will fail first , as weight is added to the center of the bridge, those supports will buckle and break. With this design they probably should have been bigger. It did fail as predicted

Original Reading was 12 cm Load (# of Steel Balls weighing. 5 lbs Deflection (initial reading – current reading) 3 ball moved it to 11. 6 12 -11. 6 =. 4 6 balls moved to 11. 3 12 - 11. 3 =. 7 10 balls moved to 10. 2 ( failed at 10 balls) 12 – 10. 2 = 1. 8 14 balls and base failed No reading There was only a small movement until the cord failed and the bridge twisted and the deck fell more than twice as much as it previously had. I wonder now if my paddle being beside the bridge instead of underneath it skewed the results?

I have built bridges before, but I have always used a weight device and never took deflection readings. I found I had made the bridge too narrow to place weights on the top of the bridge and decided to use Legos to make a hanging nest to add weights into. Once I got up near 10 pounds the basket kept failing and I had to rebuild the basket and hanging device. I really wanted to make an “ A “ type truss bridge , but once I was done , I was afraid the end posts would fail, but I decided to go ahead and try it rather than going back to make it perfect as I would have previously. This weeks article planted the seed that I don’t need to try and make everything perfect the first time. ‘