Are you ready for a challenge that will truly test your engineering skills?
As part of the 4th Croatian Conference on Earthquake Engineering (4CroCEE), we invite Master’s and PhD students from universities around the world to the 4CroCEE Shaking Table Challenge – an international competition that combines structural design, numerical modelling, experimental testing and teamwork.
Your task: design, model and build the lightest possible ten-storey balsa wood structure that withstands two earthquakes on the shaking table with the smallest displacements and accelerations – and predict its natural frequency before it is tested.
Design. Model. Test. Survive.
- 📐 Design a ten-storey structure – only a few rules, the rest is up to you.
- 💻 Model it numerically and predict its first natural frequency.
- 🛠️ Build it on site from balsa sticks and hot glue.
- 🌍 Test it on the shaking table under two earthquakes of increasing intensity.
- 🖼️ Present your solution on a poster.
The challenge at a glance
- 🪵 Material: balsa sticks (8 × 8, 5 × 8, 5 × 5 and 5 × 20 mm, 1 m long) and hot glue, all supplied by the organiser. Each team orders the number of sticks it needs.
- 🏢 Model: 10 floor levels, a plan of exactly 250 × 250 mm, the first level at 250 mm and every next one 150 mm higher, total height up to 1610 mm.
- ⚖️ Masses: 32 kg in total – 8, 8, 8, 4 and 4 kg on levels 1, 3, 5, 7 and 9, carried by threaded rods placed at one third of the span.
- ⏱️ Construction: on site, in one working day, under supervision.
- ✨ Everything else is free: number, layout and size of the elements, bracing, joints, the connection of the masses and the anchorage to the base plate. Every extra gram counts.
How the models are tested
- Weighing – the mass of the structure, without the base plate and the masses.
- Natural frequency – measured with a light hand impulse, with the masses installed.
- EARTHQUAKE 1 – a published ground motion record at reduced intensity.
- EARTHQUAKE 2 – the same record at full intensity.
During shaking we measure the peak displacement (optical tracking) and the peak acceleration (accelerometer). After each earthquake the residual interstorey drift shows the damage: the model must stay undamaged after Earthquake 1, and only limited damage is allowed after Earthquake 2. Models that exceed these limits are eliminated – they are tested further while it is safe, but they cannot win.
Scoring – 100 points
In every criterion the teams are ranked, and points are awarded by rank: the best team receives all the points of that criterion, the following teams proportionally fewer.
| Criterion | Points |
|---|---|
| ⚖️ Mass of the structure – the lighter, the better | 50 |
| 🎯 Accuracy of the predicted natural frequency | 10 |
| ↔️ Displacement – Earthquake 1 | 5 |
| 📈 Acceleration – Earthquake 1 | 5 |
| ↔️ Displacement – Earthquake 2 | 10 |
| 📈 Acceleration – Earthquake 2 | 10 |
| 🖼️ Poster presentation | 10 |
| Total | 100 |
Eliminated models are ranked behind all the others and cannot receive awards.
Poster presentation
Every team presents its solution on an A0 poster, submitted as a PDF before the competition, with a short talk at the poster. The committee scores the posters before the shaking table tests. Show us:
- the expected mass of your structure and its predicted natural frequency,
- how you expect the structure to behave, and whether you expect damage in Earthquake 2,
- how you connected the masses to the structure and how you designed the structural details,
- how you chose the final number of elements and how you optimised the mass,
- your numerical model, the variants you considered and any trial tests,
- your balsa stick order and your plan for the construction day.
Who can participate?
University teams from around the world: up to 10 teams of 4 students – Master’s students, PhD students or a mix – from structural, earthquake or computational engineering and related civil engineering disciplines. Each team names one representative.
Important dates
- 📖 Competition rules published: 16 November 2026
- 📝 Team registration: by 15 January 2027
- 📈 Ground motion record, balsa properties and mass data published: 25 January 2027
- 🪵 Balsa stick order: by 22 February 2027
- 💻 Predicted natural frequency, model geometry and screenshots of the numerical model: by 15 March 2027
- 🖼️ Poster (PDF): by 15 March 2027
- 🏗️ Construction, shaking table testing and final competition: 22–25 March 2027, University of Rijeka, Faculty of Civil Engineering, as part of 4CroCEE (Opatija, Croatia)
Teams that already submitted an Expression of Interest will receive the rules by e-mail.
Why participate?
- See how your numerical model compares with reality,
- Compete with students from leading universities,
- Gain hands-on experience in experimental earthquake engineering,
- Meet researchers and professionals from around the world,
- Show your creativity – the rules are few and the freedom is large.
Think your structure can survive the strongest earthquakes?
Join the Challenge and prove it. Questions: crocee@grad.hr