Projects / Bridge Load Lab
Bridge Load Lab
Build laser-cut 3mm birch plywood truss (Pratt, Howe or Warren from one set of members) and a solid girder of about the same mass, predict the failure load, then run an honest load-test protocol with a water bucket in 250 g steps over a padded catch tray. Trace force paths and document failure modes.
Digital guide + cut files + BOM + code · Parts sourced separately · Ages 8–14 with adult help
Pack contents
- SVG: truss members (300 mm span), pinned + roller abutments with guide rails, girder
- Assemble + load protocol guide
- First-principles: tension, compression, buckling, worked failure prediction
- Failure-mode documentation worksheet
- Verified BOM (~$14–58 hardware)
Typical hardware cost
Default structure is laser-cut birch plywood with real fasteners and hobby electronics you can source—honest BOM, not mystery modules.
- ~$14–58 in typical parts (makerspace cut toward the low end; mail-order toward the high end)
- Digital pack price ≠ hardware
The $7 pack is the digital guide + cut files + BOM + lessons + code, plus printable Builder's Corner build journal pages. Hardware is sourced separately — see Where to get kit materials. Buy with Stripe is live below.
Questions? Email us at lance.haney@gmail.com.
Pricing
- Home / Personal license $7
- Classroom license $29 — 1 teacher, up to 30 studentsOne $29 Classroom license covers one group of up to 30 students. Each additional group needs another license.
- Build materials available at cost + 10% — email for a quote
Learning outcomes
- Identify tension vs compression members under midspan load
- Assemble at least one truss and one girder span
- Execute a stepwise load protocol with abort criteria
- Document failure mode honestly