Civil Engineering Department

Spaghetti Bridge Contest

Construction Tips

  1. Try to keep design simple, using multiples of triangles.  An inverted triangle is more stable than a triangle with the apex on top.

  1. Hot glue tends to cook and melt the ends of the spaghetti, so use just enough to hold pieces together.
  2. The bearing points are the points where the bridge is supported at the ends by the edge of the gorge.  This area should be flat and smooth.  If the bearing point is not flat, the bridge may twist and break.
  3. Spaghetti may be stranded together like a cable or rope.
  4. Spaghetti is brittle and is quite strong in axial tension but very weak in compression.  The hint here is to make the compression members as short as practical, by adding internal web members.

  1. Try to make the spaghetti connections strong but flexible.  If the connections are too rigid, when the bridge starts to deflect, the joints will twist and rotate and put added bending force into the spaghetti.  Spaghetti is not very strong in bending!  In fact, if the ends of the spaghetti are cooked and weakened at the joints, then the bending forces from the joint twisting will break the spaghetti very quickly.
  2. Some people have tried boiling the spaghetti for 25 minutes and then slowly drying it while drawing the spaghetti to a longer and more slender dimension.  The result is a spaghetti member that is very flexible, light in weight yet quite strong in tension.  It is said this process makes for a good tension member but a terrible compression member!

Tips During Loading

  1. Select a maximum of two people from your group to add the load.  Try to predetermine the approximate load your bridge will carry.  The ratio of maximum load divided by bridge weight is important.  The record holding bridge from Camosun College’s Civil Engineering Technology program held almost 90 times its own weight!  This bridge used hollow tubes constructed of spaghetti for the compression members.  The following tables show the current records for each division:
Division Record Load Ratio
Up to and including grade 10
37.0
Grades 11 and 12
40.6
Technology students
86.3
Professional
97.4
  1. Apply the load gently, in suitable increments that are not too big, yet not too small either – it’s nerve wracking!  Use the heaviest weight increments first.
  2. Try not to unload then reload, this causes joints that have rotated to re-adjust and often the bridge fails sooner than expected.
  3. Keep hand and feet out of the way of falling bridge and weights.  Some bridges collapse slowly, while others disintegrate without much warning (but high drama).