Virginia and West Virginia · Balsa: supplied 1/8 × 1/8 in sticks
14 in gap · a small plate on the deck where your team chooses · no mass limit
Official rules (PDF)(opens in a new tab)The rules don't mention AI tools. Check with your teacher or the organizer before you enter a design from this site.
“your team will embark on the journey of creating a Truss Balsa Wood bridge, meticulously crafting it based on their unique plans.”Read it in the rulebook(opens in a new tab)
Soon this page will show ready-made designs for this contest, each checked against every rule below, loaded until it breaks, and buildable with a hobby knife, with a printable build pack. For now, here are the rules in plain words.
Our summary of the official rules. If anything here disagrees with the rulebook or the organizer, they win.
Where a rule can be read two ways we use the reading the organizer most likely meant and show the other. Where ours is the looser one, ask your organizer before you rely on it.
The overview's "Truss Balsa Wood bridge" makes a truss the required type.
The other reading: The word is descriptive: the overview also invites research on bridge types, so an arch would be allowed.
The clear width between the trusses exceeds 3 in.
The other reading: Out-to-out width exceeds 3 in.
The deck surface is at most 1/2 in above the support surface (a deck at the bottom, not a raised deck).
“creating a Truss Balsa Wood bridge”
“1/8 by 1/8 square cross-section balsa wood sticks, each 12 in”
“adhere them together using Elmer's wood glue”
“the overlap should not exceed 1/2 inch”
“Pins and/or gusset plates are not allowed”
“multiple plies of laminated beams glued together is prohibited”
“cover a span exceeding 14 inches, with no specified limit on the total length”
“The bridge's width must exceed 3 inches”
“loading plate ... on the deck at the same level as the support ends”
“Substructure is permitted, but the depth is restricted to a maximum of 1 inch”
“positioned 5 in from the support end, not at the center”
“either structural failure or the bridge slipping off the supports”
The other reading: Exactly at support level.
The hook is 5 in in from the support edge, at x = +-2 in; the plate plus hook mount need 1 in of headroom.
The other reading: 5 in measured to the plate edge.
Members are single sticks; extra sticks are allowed only at joints (sandwich joints).
The other reading: Members may be doubled away from joints.
To guard against slipping off, each end bears at least 1/2 in onto its support.
The other reading: Any bearing length.
The kit's stick count is not stated, so stock is not limited.
The other reading: A fixed kit count.