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Reading your contest rulebook

A checklist for reading a balsa bridge rulebook: the numbers to extract, the ambiguities to ask about, and mistakes that get bridges disqualified.

Updated · 2 min read

Every year some teams build a fine bridge that cannot compete, because it breaks a rule they missed. Spend an hour with the rulebook before you cut the first stick.

Pull out the numbers

Make a one-page sheet with:

  • The span and the support type (does the bridge rest on top, or hang between?).
  • Maximum dimensions: length, width, height.
  • The clear space the bridge must leave open, with its exact size and position.
  • The load: how much, what shape it is, where it goes and how it attaches.
  • The mass limit and how the bridge is weighed.
  • Materials: the stick sizes, whether sheet or other woods are allowed, the glue types, and whether you may use string, tape or paint.
  • Scoring: efficiency, load only, or something else, and any cap.
  • Dates and logistics: when you must submit, and whether the bridge is built on site.

Find the ambiguities

Rulebooks are written fast, and many contain a sentence that can be read two ways. Common ones:

  • Does "no more than 100 g" include the load hook?
  • Is the clear space measured inside the bridge or from the supports?
  • Does "no gussets" forbid small corner pieces?
  • Is the glue amount limited by weight or just by type?

Write the question down and ask the organizer in writing. Keep the reply. If you can't get an answer, build to the stricter reading.

Check the help rules

Some contests limit how much outside help a student may use on the design, including AI tools, and some ask you to explain how you designed your bridge. Read that section too, and when in doubt ask your teacher or the organizer. Build the bridge yourself and say where your ideas came from.

Mistakes that get bridges disqualified

  1. Over the mass limit on the contest scale, because yours reads differently.
  2. Not enough clear space for the loading rod or car.
  3. Using a banned material, such as the wrong stick size or an extra glue.
  4. Wrong span, because the bridge is too short to rest on the supports.

Measure the finished bridge against your sheet one last time.

Let us help

On our contest pages we put each rulebook's rules in plain words and say where we read an unclear rule one way. Our reading is a convenience, not a ruling. The organizer's word is final.