a) Glue and work slowly, carefully and according to a design.
b) The total wood that you will have to complete your bridge is 15000mm. In general each truss takes 7000mm and the cross bracing and extras take about 1000mm.
c) Use cross bracing and diagonal cross bracing to prevent the bridge from failing due to sideways movement.
d) Wood is strong in tension, weak in compression and even weaker in bending.
e) Transfer the load into the strengthened top compression member via tension members. The compression member must then transfer the load from the top centre of the structure away into the supports.
f) Mix the 2 halves of the epoxy resin in small and equal amounts as the glue gets it strength from a chemical reaction and dries quickly.
g) Use West Point Bridge designed to give you an idea of where the stress in your design occurs. Blue members are undergoing tension and red members compression. The darker the colour the more the stress.
h) Remember that wood under compression wants to buckle and snap and wood under tension wants to dislodge itself from its joint.
i) Use all your material but make sure you use it in the correct place.
j) Transference, dissipation and the material properties of the wood and glue must be intelligently applied not to focus the stress that the loading harness applies back into the bridge.
k) Oil on your hands cause glue failure.
l) Look at the photographs of previous winners and competition participants to get an idea of what good bridges look like.
m) Use clothing pegs or masking tape to hold the glued wood in place while drying.
n) Use Lions matches to mix and apply small dabs of glue to the wood.
o) Use cutting pliers to easily snip the wood.
p) Use A 4 typing paper to mix the epoxy resin glue on.
q) A Tape measure, calculator and a piece of string that is 6500 long will make measuring the length of the wood you have used in one truss easy.
r) Build your truss from the 1:1 cut and build template to make sure both trusses are exactly equal.
