Try to keep design simple, using multiples of triangles. An inverted triangle
is more stable than a triangle with the apex on top.
Hot glue tends to cook and melt the ends of the spaghetti, so use just
enough to hold pieces together.
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.
Spaghetti may be stranded together like a cable or rope.
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.
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.
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
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:
Record Load Ratio
Up to and including grade 10
Grades 11 and 12
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.
Try not to unload then reload, this causes joints that have rotated to
re-adjust and often the bridge fails sooner than expected.
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).