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Frequently Asked Questions

​General Questions

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  • Will middle school teams compete against high school teams?
    ​No. We will have separate competitions for middle schools and high schools.
  • Can teachers or schools enter more than one model bridge?
    No. We will accept one model bridge entry per school.
  • Can individual students enter the competition?
    ​The competition is designed to encourage students to work in teams with the teachers acting as facilitators. Therefore, the N.C. Department of Transportation strongly encourages teams of at least two students with one or more teachers as facilitators. If it is impossible for a school to develop such a team, then a student with a teacher as a facilitator will be allowed to enter the competition.
  • Are you offering the competition next year?
    ​Yes, the competition is an annual event.


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  • Your guidelines specify “no element wider nor deeper than 1/8 inches.” Does that apply to joints? For example, can two 1/8-inch x 1/8-inch wood pieces cross each other to make the joint 1/4-inch? Or would we need to use 1/16-inch x 1/16-inch wood strips?
    ​The 1/8-inch x 1/8-inch size requirement does not apply at joint intersections. However, the intersection cannot exceed the size of two individual members, total of 1/4 inch. This is only allowed at the joint areas.​
  • I would like to put spacers between two pieces of balsa wood, with the measurement of the entire member (balsa wood pieces and spacers) exceeding 1/8 inches. Would the spacers be ruled as joints, making my bridge legal?
    ​If a spacer is continuous, then a laminated member results. The spacers will be counted as individual members. Each individual member cannot exceed 1/8 inch as outlined in the guidelines.
  • The guidelines say commercially available balsa. Does this eliminate the basswood kits that are often used in physics labs?
    ​Basswood may not be used. Only balsa wood may be used for the competition.
  • Are cross-members allowed under the balsa wood deck?
    ​Yes, cross-members are allowed under the balsa wood deck.
  • ​Are gusset plates allowed at joint connections?
    Yes, one per joint is allowed. The plate, however, cannot exceed 1/8 inch in thickness and 1/2-square-inch in area.​
  • What type of glue can be used? Our class was wondering if adhesives, such as rubber cement, liquid nail or epoxy styrene resin allowed? Or does the label have to say glue for it to be considered glue?
    ​The label does not have to say glue for it to be considered glue. If it is an adhesive that can be used to bond two pieces of wood together, it is acceptable. Any type of glue may be used.
  • Is there a drawing or design program that is preferred to create our plans?
    We do not require that software be used to create drawings. Drawings may be drawn to scale by hand using drafting tools such as straight edges, triangles and compasses. There are also many drawing, design and testing software packages available. Because we do not know what resources or technical support is available at any given school, we do not endorse any particular software.

    REMEMBER: The goal of the drawing is for an engineer to be able to build your bridge from that drawing.

Design & Product

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  • Is a 10-pound container used as a basis for the weight held up to be 20 kilograms?
    ​The bridge must carry an initial load consisting of a container and the testing hardware. Dry sand will then be added slowly and carefully to the container.
  • May we paint our bridge? May we use wood laminate?
    ​Painting is not allowed, since it could provide some structural benefit. Laminated members are not allowed.
  • ​Can we notch the wood?
    Yes, the wood can be notched.


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  • Can PowerPoint be used in the presentation?
    ​PowerPoint presentations are not required, but if you choose to use one, a PowerPoint presentation may only be used at the Bridge Building Competition Finals. Any slides supporting your presentation must be in PowerPoint from Microsoft Office 2003, 2004 or 2010. Remember, the total presentation may not exceed 7 minutes, including setup and breakdown.

    Please send your PowerPoint presentation to Sterling Johnson at and include a PDF of your report and drawings by the specific due date.

  • For the two-page report, do you want a bibliography? Also, are footnotes required?
    ​No, since this was not specified in the competition guidelines, the inclusion or exclusion of a bibliography and footnotes is up to the individual teacher. It will not be a part of the judging requirements.

7/9/2019 11:12 AM