This semester, eight civil engineering students at EPFL will take part in a slightly off-the-wall challenge: they are building a reinforced-concrete canoe that they will then race in a university regatta in Germany. The team has just submitted its engineering design to the evaluation panel.
‘We got the idea by talking with civil engineering students in the United States and at ETH Zürich, and decided that EPFL should participate in the competition as well,’ says Charles Jeanbart, president of EPFL’s Civil Engineering Student Association (AEGC), the organization behind the project.
A team of eight students is spending the semester designing a canoe made of reinforced concrete. An annual Concrete Canoe Competition is already a tradition for many US and Canadian universities and has also been held in Europe - mainly in Germany - since 1986. This year, the ‘Betonkanu Regatta’ will take place in Cologne from 9-10 June. A record 50 universities from around the world will compete on Fühlinger See, an artificial lake in the German state of North Rhine-Westphalia.
The EPFL team has just submitted its engineering design to the evaluation panel, thereby securing its place in the competition. This is crucial for the competition since the most prestigious award goes to the team with the best design, especially in terms of innovation. But even if they don’t win this award, they can still fight in other categories: lightest canoe, heaviest canoe, best-looking canoe, or fastest canoe. There is also a booby prize for the unluckiest crew. The regatta is divided between men and women, and includes a 100-meter stretch and a slalom.
‘Like IKEA furniture’
Designing the canoe is the semester project for the eight master’s students who are overseen by Professor Aurelio Muttoni. On top of the engineering challenge inherent in making concrete float, the students must also follow strict design specifications set forth in the competition’s rules and regulations; for instance, the canoes can contain no more than two kilograms of synthetic materials in addition to the concrete. There are also limits on how long and wide the canoes can be. ‘This is our first time in the competition, so we have to learn everything from scratch,’ says Hanne Cloesen, a student on the EPFL team. ‘We decided to build a five-meter-long canoe made up of three sections that can be taken apart - like IKEA furniture - to make it easier to transport. And we used a bridge-building method called pre-stressing to make sure the whole thing stays together.’ Taking a page from IKEA, the students named their canoe Kånöepfl and wrote their design paper as if it were a set of assembly instructions.
Textile-reinforced concrete and pre-stressing cables
The students initially built a 1:5-scale model and tested it in a fountain. Then, when building the real thing, they experienced a few setbacks in applying the concrete layers by hand. ‘We had to make sure there were no surface defects and that the joints holding the three parts together were watertight. We alternated the layers of concrete with layers of carbon fiber, which has the advantage of being ultralight. It turns the concrete into textile-reinforced concrete,’ says team-member Stephan Mühlberg. But the students have another ace up their sleeve: they also used steel pre-stressing cables (typically used in bridges) that compress the concrete and hold the three parts of the canoe in place. The team’s novel approach is what convinced Professor Muttoni to head the project. ’In our Structural Concrete Laboratory, PhD student Patrick Valeri is looking into potential applications for textile-reinforced concrete - especially for eco-friendly buildings, since carbon fiber makes concrete corrosion-resistant and therefore cuts the amount of CO2 generated in concrete production,’ said Muttoni.
Looking for more sponsors
The students will also be the ones paddling their canoe in the regatta and have already started an intense training program at EPFL’s Viv’Eden gym, which is one of the team’s sponsors. Other sponsors include EPFL’s Educational Affairs office (DAF), the student association (AGEPoly) and the Civil Engineering section (SGC). The Civil Engineering Student Association, which is handling all project logistics, is seeking additional sponsors to cover the expenses, which are estimated at CHF 20,000.